Release Notes

flow5 v7.26.2, November 9, 2024

General
- fixed the inversion of the speed and bank angle variables in the serialization of plane polars
Modelling/Meshing
Analysis
- fixed NaN issues in the calculation of Cp on quad panels with a zero-length side
Post-processing
UI
Other

flow5 v7.26.1, November 7, 2024

General
Modelling/Meshing
- fixed a crash bug occurring when defining a new plane from scratch
Analysis
- fixed issues in the calculation of Cp on quad panels with a zero-length side
Post-processing
- minor improvements to the display of wing Cp curves
UI
Other

flow5 v7.26, November 3, 2024

General
- the format of the .fl5 project file has been modified; NEWLY SAVED FILES MAY NOT BE READABLE BY VERSIONS OLDER THAN v7.26
Modelling/Meshing
- fixed issues when using flapped foils with hinge location close to the T.E.
Analysis
- fixed minor issues in the plane scripting module
- added the wing's root bending moment to the list of optimization targets
- fixed the incorrect evaluation of the bending moment in the case of quad methods
- corrected the wind axes in the case of beta polars: changes the calculated lift and drag coefficients
- added the bank angle φ as a variable in 3d analyses and to the list of variables in the polar graphs
Post-processing
- minor improvements to the flow animations
- fixed an occasional crash bug when displaying streamlines
UI
- fixed some window issues specific to dual screens on linux X11
Other

flow5 v7.25, April, 2024

General
Modelling/Meshing
- fixed several bugs in the export/import process of sails to xml files; format modified in the case of spline type sails
Analysis
- fixed the inverted angle of beta int the sail module which was accidentally introduced in v7.24 while fixing signs in the plane module
- fixed the issue with the scripted VLM analysis of planes which caused the fuselage panels to be inadvertently included
- added an option in plane and boat scripts to export meshes to STL
Post-processing
UI
Other

flow5 v7.24.1, December 9, 2023

fixed the ineffective saving of graph variables in the application's settings

flow5 v7.24, December 8, 2023

General
- the format of the .fl5 project file has been modified; NEWLY SAVED FILES WILL NOT BE READABLE BY VERSIONS OLDER THAN v7.24
- updated the code for compatibility with Qt6; the binaries are still released with the Qt5 libs for maximum compatibility with all platforms
- added a documentation page on the matter of higher lift predictions in the case of thick surface methods
Modelling/Meshing
- overhaul of the foil modification methods for simplicity and robustness
- improved the construction of the foil's leading edge and of the mid camber line around the L.E.
- improved the module to design and approximate a foil using one spline
- added options to copy wings and fuselage from one plane to another
Analysis
- overhauled and aligned all force, moment and derivative signs :
  - In the output of the non-dimensional stability derivatives, changed the incorrect labels of CLu, CLa and CLq to CZu, CZa and CZq respectively. CLx and CZx have opposite signs since the wind's z_axis is pointing up and the stability's z-axis is pointing down; this has been an opportunity to update the benchmarking against AVL
  - changed the output of lateral moment coefficients Cl and Cn to be in wind axes instead of body axes
  - fixed the inverted sign of beta in T6 polars; now consistent with T5 polars, with the convention used in AVL and with the 3d view display; existing polars will need to be recalculated;
  - fixed a bug which caused the body panels to be occasionally ignored in the calculation of moments
  - corrected a bug in the display of the 1/4 chord pitching moment in the operating point view in the case of triangle methods
  - this has been an opportunity to clarify axes and moment conventions used in flow5
- added the "Closed_Inner_Side" field to the wing's xml definition file
- various improvements and bug fixes to the plane optimization module
- fixed a crash bug in the 2d foil optimization module
Post-processing
- added an option to change all graph variables in one action in the plane polar and operating point views; the option is located in the screen's bottom right container
UI
- fixed view updates in the floating 3d view
- fixed a crash bug when deleting a foil in the operating point view
- fixed a few more minor display bugs here and there
- added an option to set a default toolbar icon size
- removed all support for OpenGL versions older than 3.3; this had become a necessity to reduce the maintenance workload and to simplify the code
Other
- fixed the bug which caused the export of a boat as a project to generate a corrupted file

flow5 v7.23, June 4, 2022

General
- fixed a crash bug occurring when exporting data from an analysis of an STL plane
- fixed a crash bug occurring when importing pre-v6.49 .xfl files
Modelling/Meshing
Analysis
Post-processing
UI
Other

flow5 v7.22, January 27, 2022

General
- the format of the .fl5 project file has been modified; NEWLY SAVED FILES WILL NOT BE READABLE BY VERSIONS OLDER THAN v7.21
Modelling/Meshing
- fixed an occasional crash bug when connecting triangular panels
Analysis
- fixed an error in the construction of wake panels in the case of models imported from STL meshes; this impacts the estimation of the induced drag.
Post-processing
UI
- added an experimental option to visualize flows;
- fixed a bunch of minor issues in the 3d displays
Other

flow5 v7.21, December 19, 2021

General
- the format of the .fl5 project file has been modified; NEWLY SAVED FILES WILL NOT BE READABLE BY VERSIONS OLDER THAN v7.21
Modelling/Meshing
- fixed an incompatibility between the re-use of existing RHS solutions and ground effects
Analysis
- added an option to model the water's free surface intended for hydrofoil analyses;
  performed a benchmark with the results of Nasa report 1232.
Post-processing
UI
Other
- fixed a data corruption bug when duplicating external polars

flow5 v7.20, December 11, 2021

General
Modelling/Meshing
- fixed a crash bug occuring when modifying wings with small spanwise surfaces
- fixed a crash bug occuring when connecting panels in the case of a thin surface analysis
- added an option to check element edge lengths
- added an option to export/import airfoil .dat files together with the wing's xml file; the option is set in the preferences Save/Export options"
Analysis
- Added a verification of compatibility of vortex core size and element edge length at the start of the analysis; the core size should be smaller than 1/50 the length of the smallest triangle edge, otherwise the analysis will not run.
Post-processing
UI
Other
- fixed some compatibility issues with xflr5
- fixed a few more minor bugs

flow5 v7.19, October 18, 2021

General
Modelling/Meshing
Analysis
- corrected an error in the construction of the VPW in the case of an analysis with side slip; the beta angle was applied twice; second order impact on results
Post-processing
UI
- fixed the incorrect display of the vortons in the case of a T6 analysis with side slip
Other
- fixed a few more minor bugs

flow5 v7.18, September 15, 2021

General
Modelling/Meshing
Analysis
- homogenized the signs of roll and pitch moment coefficients resulting from T5, T6 and T8 analyses; T5 analyses may need to be re-generated.
Post-processing
- fixed issues related to the export of operating point data to the clipboard and to text files
UI
- fixed minor display issues in the rendering of triangular panels
- made minor improvements to the dynamic scaling of graphs
Other
- fixed an occasional crash bug occuring after the LLT analysis of a plane with a fuselage

flow5 v7.17, August 22, 2021

General
Modelling/Meshing
- added an alternative method to connect the fuselage and wing meshes
- fixed crash bugs occurring during mesh connections in the plane editor
Analysis
- enabled the batch mode for LLT analyses
- removed the existing restriction to 4 threads of the optimization loop
- fixed the crash bug when running a scripted LLT analysis on a wing with flaps
- added panel data to the export of operating points to text files; cf. field "export_oppoint_Cp" in the template script
Post-processing
UI
Other
- fixed the bug which prevented to load .plr files generated in xflr5v6.49 format

flow5 v7.16, August 1, 2021

General
- changed the packaging method of the linux package to support the oldest LTS distribution of Ubuntu (i.e. 18.04)
- updated the import of .xfl files to be compatible with xflr5 v6.49 - flow5 v7.16 REQUIRES THE INSTALLATION OF XFLR5 v6.49
Modelling/Meshing
- added options to control the precision of wing exports to STEP files
Analysis
- added the freestream velocity field to the xml format of T5 polars
- added the the stability derivatives to the export files of T8 operating points
- added an option to set the auto-inertia flag in wing and fuselage xml files
Post-processing
UI
- corrected a bunch of minor bugs
Other

flow5 v7.15, June 28, 2021

General
Modelling/Meshing
Analysis
- activated the scripting feature for T5 and T8 analyses; cf. the updated script file;
  updated xml templates for both analysis types can be generated by exporting an existing polar to xml in flow5.
- fixed a bug which created a conflict in the plane optimization module between wing section data and wing scaling data
Post-processing
UI
Other

flow5 v7.14, June 15, 2021

General
- the format of the .fl5 project file has been modified; NEWLY SAVED FILES WILL NOT BE READABLE BY VERSIONS OLDER THAN v7.14
Modelling/Meshing
Analysis
- corrected an error in the calculation of flap moments in the case of the tri-uniform method.
- added wing section data to the variables of the optimization module
- added an option to enter a user defined friction coefficient for the fuselage drag
Post-processing
UI
- more optimization of OpenGL methods for improved rendering speed
- more tweaks to improve the rendering of icons on high dpi screens
Other

flow5 v7.13, May 23, 2021

General
- the format of the .fl5 project file has been modified; NEWLY SAVED FILES WILL NOT BE READABLE BY VERSIONS OLDER THAN v7.13
- fixed a bunch of broken links in the online documentation
Modelling/Meshing
- corrected minor mapping errors of the geometry and mass parameters when exporting to AVL files
- changed the definition of the product of inertia Ixz to be the positive instead of the negative sum as explained here. The sign error in the assembly of the inertia tensor has been corrected, with minor impact on the lateral modes
Analysis
- the solution method to the panel analyses has been modified to take better advantage of the problem's linearity
  - the detailed explanations are given here
  - the change of logic has enabled the addition of the Type 8 analyses
  - this has been an opportunity to perform another round of benchmarking against AVL
- corrected a sign error in the calculation of the derivative CXq in the case of triangle analyses; went unnoticed because this derivative is unused
- disabled the option to set parametric surface angles in the stability analyses: not forward compatible with the simplification of panel analyses
- fixed a crash bug which occured in the case of stability analyses with the tri-linear method
Post-processing
UI
- made some tweaks to improve the rendering on high dpi 4K monitors
- fixed the issues with the roll/pitch/yaw sliders and the auto z-rotation in the fine 3d controls
- added an option to set a custom size for the symbol on curves; the size is set in the Preferences/Graph/Other
Other
- code cleaning

flow5 v7.12, May 10, 2021

General
- fixed a crash bug which prevented the loading of large project files in Windows
Modelling/Meshing
Analysis
- restored the type 5 beta polars; this has been an opportunity to perform another round of benchmarking
- corrected an error in the calculation of pressure coefficients in the case of thin surface analyses
Post-processing
UI
- enabled the copying of multiple analyses from one plane to another in a single operation
- fixed minor bugs related to the use of locale settings for number formatting
Other
- code cleaning

flow5 v7.11, May 2, 2021

General
- fixed a bug which prevented the loading of files generated with versions older than beta 18
Modelling/Meshing
Analysis
- fixed the crash bug in plane batch 2 analyses
Post-processing
- fixed a bug which prevented the dynamic update of operating point data in the 3d view and in the polar graphs
UI
- more optimization of OpenGL methods for improved rendering speed
Other
- code cleaning

flow5 v7.10, April 26, 2021

General
Modelling/Meshing
- fixed the bugs linked to foil leading edge flaps
Analysis
Post-processing
UI
- restored the dynamic selection of objects in the plane tree view when using the keyboard arrows
- fixed display issues on macOS for OpenGL context > 3.1
- deprecated the support for OpenGL contexts < 3.3 since all graphic cards less than 10 years old support OpenGL 3.3; support for OpenGL 2.1 will be removed in a future version.
- optimized the OpenGL methods for improved display speed
- other minor bug fixes and improvements
Other
- tested successfully flow5 on macOS M1 mini
- modified the save sequence of project files to prevent accidental file corruption
- permanently disabled the auto-save feature to prevent accidental file corruption
- removed occasional crash bugs and minor memory leaks
- code cleaning

flow5 v7.09, April 18, 2021

General
Modelling/Meshing
Analysis
- added an experimental module for 3d inverse design
- added a documentation page on the matter of Cp Coefficients
- made various bug corrections and improvements to the plane optimization module
- corrected an error in the calculation of stability derivatives in the case of trilinear analyses
- optimized the construction of RHS vectors for reduced build times
- fixed the bug which caused the single-precision calculations to fail
Post-processing
UI
- improved the shader used to display panel forces
- fixed some minor issues with the import of external curves in graphs
- made minor improvements to the SVG export functions
Other
- code cleaning

flow5 v7.08, March 31, 2021

General
- finished a first set of comparisons of sail measured performance to flow5 predictions; since these preliminary results tend to show that panel methods for flows around sails are limited to narrow upwind conditions, the sail module will not be developed any further on the short term with the effort focusing instead on the plane/hydrofoil module.
Modelling/Meshing
- corrected a bug in the construction of free meshes in the case of spline type sails
- fixed trailing edge issues in the case of imported STL sails whenever the sail is modified through transformations
- changed the orientation of spline sail panels in the case of ruled meshed for consistency with free meshes
- fixed minor issues in the import process of sails from STEP files
Analysis
- added an option to switch planes from within the optimization module
- restored the missing extra drag in a boat's analysis results
Post-processing
- fixed the inverted display of Cp and Gamma in the case of tri-linear analyses of sailboats
- fixed a crash bug when exporting a boat's operating point data to a file
UI
- made minor improvements to the interface of the plane optimization module
Other
- code cleaning

flow5 v7.07, March 20, 2021

General
Modelling/Meshing
Analysis
- added an optimization module for airplanes.
Post-processing
UI
- fixed minor display issues in macOS
Other
- fixed minor memory leaks
- code cleaning

flow5 v7.06, February 20, 2021

General
- the format of the .fl5 project file has been modified; NEWLY SAVED FILES WILL NOT BE READABLE BY VERSIONS OLDER THAN v7.06
Modelling/Meshing
- minor tweaks, improvements and bug corrections to the thin sail free mesh module
- activated the export of spline type sails to STEP files
Analysis
- fixed a crash bug in the LLT analysis occurring when no operating point is generated
- fixed the inoperative angle variables in T6 control polars
- added a field to the plane script to export all plane operating points to text files; see the updated template.
Post-processing
UI
- minor tweaks to the menus and shortcuts
Other

flow5 v7.05.1, February 8, 2021

UI
- fixed the bug specific to mac OS which caused menu buttons to be non interactive; fixed by reverting to Qt 5.12 instead of Qt 5.15; the dmg package has been updated with the same download link

flow5 v7.05, February 7 2021

General
- the format of the .fl5 project file has been modified; NEWLY SAVED FILES WILL NOT BE READABLE BY VERSIONS OLDER THAN v7.05
Modelling/Meshing
- activated the inclusion of the hull in sailboat analyses;valid only for fully emerged hulls such as in the case of the AC75
Analysis
- corrected a bug in the case of triangle analyses with ground/water effect which caused the contribution of the mirror wake to be ignored; slight effect on results
- corrected an error in the calculation of velocity vectors in the wake in the case of triangle methods; impacts mainly the shape of the streamlines and of the VPW; minor effect on results in the case of the VPW
- replaced the input of AWS an AWA by TWS and TWA for sailboat analyses
- fixed a crash bug when trying to run a plane analysis without a main wing
Post-processing
- added the TW properties to the variables of sailboat polar graphs
UI
- added more number localization
Other

flow5 v7.04 January 25, 2021

General
- added on option to use locale settings for number formatting; the option is set in the Preferences/Application interface --- WORK IN PROGRESS ---
Modelling/Meshing
- corrected bugs in the construction of ruled meshes of spline type sails; MESHES BUILT IN PAST VERSIONS MAY NEED TO BE RECONSTRUCTED IN v7.04
- corrected an occasional crash bug when duplicating a spline type sail
Analysis
- fixed the incorrect velocity range in the case of T6/1 control polars
- fixed the non-varying mass parameter in T6 polars
- fixed issues with the linear system solver in the case of the 2d IBL method
Post-processing
UI
- fixed a number of minor issues with the 2d IBL solver
Other

flow5 v7.03 January 16th, 2021

General
- the format of the .fl5 project file has been modified; NEWLY SAVED FILES WILL NOT BE READABLE BY VERSIONS OLDER THAN v7.03
- replaced all calls to LAPACKE routines by calls to LAPACK to enable the use of the native framework vecLib instead of MKL on macOS; the binary version of v7.03 for macOS is now linked to vecLib; the performance is comparable to that of the MKL version.
Modelling/Meshing
- added options to export wing surfaces as NURBS or swept splines to a CAD file
- fixed length unit issues when exporting shapes to a STEP file
- improved the ruled and free meshers for Spline and NURBS sails
- corrected the inverted value of the taper ratio
- made minor improvements to the design interface of solid thick sails: Windsurf.html
Analysis
- added the boat speed as a variable to sail boat analyses; enables the computation of the AWA as a function of altitude
Post-processing
- fixed minor things in the stability time graphs
UI
- modified the filter in the object view to filter separately objects and polars
- improved the dark mode override settings
- fixed various minor display bugs
Other
- fixed a crash bug when importing legacy .xfl project files containing operating points

flow5 v7.02 December 6, 2020

General
Modelling/Meshing
- added the sail reference dimensions to the xml files
Analysis
- added an option to duplicate an existing analysis from another plane or boat (Ctrl+Shift+D)
- fixed length unit issues in the VPW definition of sailboat analyses
- fixed various issues with scripting of boat analyses
- added the spline type wind gradient to the boat analysis xml export/import
- added the rotation around Y to the variables of a sail analysis - intended for windsurfs
Post-processing
UI
- added a dark mode override for the application's style for Windows OS
- added a customizable filter on object and polar names in the object tree views
- added an option to customize the view scale factor when using the mouse wheel
- simplified the interface to insert an existing project file
- cleaned a few minor bugs
Other
- fixed a crash bug when importing legacy .xfl project files containing operating points

flow5 v7.01_beta_19 November 23, 2020

General
- the format of the .fl5 project file has been modified; NEWLY SAVED FILES WILL NOT BE READABLE BY VERSIONS OLDER THAN BETA_19
Modelling/Meshing
- added options to build free meshes as an alternative to ruled meshes for internal NURBS-type and Spline-type sails
- added a parameter to control mesh growth from the edges inwards
- fixed a crash bug when trying to display the panels of the hull in the boat editor
- fixed a crash bug when trying to move mesh nodes in the plane editor
- fixed a crash bug when trying to animate the mesh construction
Analysis
- modified the specification method of the wind gradient in the case of sail analyses so that it is defined with a spline and not as a parabola
- modified the calculation of the discard distance of vortons which is now measured from the origin of the body axes
Post-processing
- fixed a crash bug when trying to display streamlines in the sailboat view
- corrected the export of foil polars to include all the polar data
UI
- corrected a bunch of minor bugs in the sail module views
- restored the disabled foil menu when no foil is loaded
- improved the interface to load background images in the 2d and 3d views
- fixed minor UI bugs here and there
Other

flow5 v7.01_beta_18 November 15, 2020

General
- the format of the .fl5 project file has been modified; NEWLY SAVED FILES WILL NOT BE READABLE BY VERSIONS OLDER THAN BETA_18
Modelling/Meshing
- improved the options to import sails from external STEP or STL files: External_Sails.html
- corrected some mesh construction issues in the case of sailboats
Analysis
- optimized the calculation of the VPW to take better advantage of multi-threading
- modified the stability analyses to include AVL-type controls; see the detailed explanations here
- deprecated the inertia parameters in the stability analyses
- modified the xml analysis files to include the AVL-type controls and to remove the deprecated inertia parameters
- modified the algorithm to better evaluate the Cp coefficients on panels connected to only 2 neighbours
- deprecated and removed the advanced editor for plane analysis objects
Post-processing
- corrected the missing update of streamlines in the plane's 3d view when changing the operating point
- corrected the 3d display of forces on panels with normals aligned with the negative z-axis
- added lift and drag coefficients in wind axes to the list of variables in the sail polar graphs
UI
- Added an option to load a background image in the 3d views
Other
- deep code cleaning

flow5 v7.01_beta_17 October 25, 2020

General
- added online documentation for the STL type sails
- the format of the .fl5 project file has been modified; NEWLY SAVED FILES WILL NOT BE READABLE BY VERSIONS OLDER THAN BETA_17
Modelling/Meshing
- added an option to define thin sails from STL meshes
- added an option to multi-thread the fuselage cut operation; can be disabled in case the OCC algorithm turns out to be unstable
- restored the saving of panel distribution types for wing-type sails
Analysis
- restored a simplified and more robust version of the VPW live update
- restored the missing wind gradient factor in the sail analysis
Post-processing
- corrected a bug which prevented the AVL type drag to be deleted from an existing polar
- corrected a crash bug when trying to edit a sail analysis without AVL-type drag
UI
- corrected a crash bug when exiting the plane editor in the case of a plane without a fuselage
- corrected minor bugs in the spline to foil editor
- corrected a bunch of bugs in the sail analysis module
- more tweaks
Other
- fixed a few more occasional crash bugs
- code cleaning

flow5 v7.01_beta_16 October 10, 2020

General
- added online documentation for the OpenGL settings
Modelling/Meshing
- corrected a bug which caused the inertia of STL-type planes not to be computed when loading the project
- added an option to scale xfl-type planes; also scales the position of the lumped masses
- moved the fuse mesh operations to a separate thread to enable cancelling when multithreading
- made more tweaks to the mesher to improve its robustness and the quality of the resulting mesh
- corrected a crash bug when trying to export a wing with an open TE to a STEP file
- corrected a bunch of minor bugs in the xfl-type fuselage editor
Analysis
- changed the input method of the vorton core size which is now entered as a fraction of the reference chord
- removed the option to set the VPW streamwise progression factor which is now hard-coded to the value 1
- changed the evaluation method of influence coefficients in the case of tri-uniform analyses, to eliminaite numerical errors in case of perpendicular triangles
Post-processing
- added an option to modify the extra drag and AVL-type parabolic drag without deleting the rest of the polar data
UI
- improved the responsiveness of the GUI when selecting planes, polars, and operating points
- corrected an incorrect scaling of the vorton display size when changing units in the preferences
- fixed a bunch of bugs in the sail analysis module
- removed some obsolete or useless features
Other
- fixed a few more crash bugs and other minor issues
- code cleaning

flow5 v7.01_beta_15 September 23rd, 2020

General
- the format of the .fl5 project file has been modified; NEWLY SAVED FILES WILL NOT BE READABLE BY VERSIONS OLDER THAN BETA_15
- updated the recommendations for the VPW settings
- added online documentation for the fuselage import from CAD files
- added online documentation for the surface mesher
- added online documentation for plane batch analyses
Modelling/Meshing
- improved the surface mesher for speed of execution and mesh quality
- corrected various modelling bugs in the case of wing type sails
- improved the shape healing features of the CAD fuse editor
- added an option to scale the background image in the xfl type fuselage editor
Analysis
- moved the vorton core size, the VPW length and the VPW iterations from the global settings to the analysis definition
- optimized the VPW calculations for faster execution
- disabled the option for live updating of the VPW during the analysis: creates too much code complexity and too many potential instabilities */
- simplified the batch mode for plane analyses - uses now the pre-loaded analyses instead of xml files
- corrected some bad crash bugs and other minor things in the plane batch analysis module
- added optional AVL type parabolic profile drag to the polar; this is intended for STL-defined planes to compensate for the missing airfoil viscous drag
Post-processing
- Fixed the empty display of the fuse drag variables in the polar graphs
GUI
- corrected minor display bugs in the 3d sail views
Other
- corrected crash bug issues when loading projects including sailboats
- added a specific user-defined directory for STL files
- removed updates of user-defined directories on load/save operations
- code cleaning

flow5 v7.01_beta_14 September 3rd 2020

General
- the format of the .fl5 project file has been modified; NEWLY SAVED FILES WILL NOT BE READABLE BY VERSIONS OLDER THAN BETA_14
Modelling/Meshing
- made various optimizations and bug corrections to the operations on STEP/IGES type fuselages
- improved the robustness of the surface mesher
- corrected an error and a crash bug in the import process of STL files
- improved the STL plane reader
- corrected the unit factor when exporting meshes to STL; meshes will be written using the active length unit
- added an option to import a plane's inertia from another plane
Analysis
- activated the analysis of planes defined by STL meshes; see the detailed explanations and step-by-step tutorial. EXPERIMENTAL.
- fixed an occasional crash bug due to thread conflicts when constructing RHS vectors; as an indirect consequence RHS constructions are slightly slower than in beta 13
- corrected triangle connection errors in case of very thin trailing edges
- corrected an error in the evaluation of the moment induced by the pressure forces acting on the fuselage
Post-processing
- restored the animation of stability modes and corrected the display of the roll mode
- corrected a bunch of minor bugs affecting the 3d view and the graphs
GUI
- improved the display of formulas for OS dark mode settings
Other
- corrected a bug when exporting a plane with no foils as a project
- code cleaning

flow5 v7.01_beta_13 August 9th 2020

General
- the format of the .fl5 project file has been modified; NEWLY SAVED FILES WILL NOT BE READABLE BY VERSIONS OLDER THAN BETA_13
- modified the management of the max. thread count which is now made at application level instead of task level
- fixed project loading issues with boat polars
- removed a minor memory leak ocurring when discarding a wing edition
Meshing
- Reduced the minimum acceptable size of triangular panels
Analysis
- modified the analysis method for T6 polars: the analyses are now performed in stability axes instead of body axes; this is to simplify calculations with sideslip or ground effect; no impact on results which are converted back to body axes. Due to a modification of the 3d display rendering method, the operating points with vorton wakes will need to be re-created.
- activated the sideslip for T6 analyses: Jibe2_lateral
- activated the ground effect for the T6-VPW: Ground effect
- added various minor optimizations to reduce the computation times of T6-VPW analyses
Post-processing
- cleaned-up the main 3d view to better represent wake panels and vortons
- added lift and drag forces in wind axes to the list of variables of polar graphs
- corrected a missing velocity scale factor in the display of strip forces
- removed the option to display surface velocities - not useful and induces too much code complexity; replaced by the option to display the perturbation velocities in a crossflow plane.
GUI
- modified the surface colour picker to use Google's material design colours

flow5 v7.01_beta_12 July 20th 2020

This version introduces the Vortex Particle Wake. A description, a tutorial and a comparison to wind tunnel test results can be found in these documents:
Building_blocks.html
VPW.html
Jibe2.html

You can also choose to watch the live explanations and the demo on Youtube:
flow5 - Introduction to the Vortex Particle Wake
flow5 - The Vortex Particle Wake
flow5 - The Jibe2 experiment
flow5 - VPW roll-ups (no commentary)

General
- the format of the .fl5 project file has been modified; NEWLY SAVED FILES WILL NOT BE READABLE BY VERSIONS OLDER THAN BETA_12
Modeling
Meshing
- modified the position of the control point on degenerate quad panels at the side's LE and TE to be at the triangle's COG; very minor impact on results
Analysis
- first activation of the Vortex Particle Wake - EXPERIMENTAL
- corrected an error in the analyses of quad polars with ground effect; the induced drag was incorrectly evaluated - significant impact on results
- corrected the construction of the RHS vector in the case of control polars applied to planes with a fuselage; the RHS components were set to 0 on the fuselage; minor impact on results
- corrected an error which caused the last triangle of the wake columns to be skipped in triangle analyses; very minor impact on results
- disabled the Neumann BC for thick bodies - the method is inherently unstable
- disabled the LE and wing shape parameters in control polars - not of great use for prohibitive added complexity
- disabled the evaluation of lift and drag by summation of panel forces - imprecise results
- enabled viscous interpolation from Cl for T6 analyses; these analyses are incompatible with the viscous loop
- improved the convergence of T2 LLT analyses
GUI
- grouped all the 3d scale controls into one tabbed widget
- set the same scale for surface velocity and downwash velocity
- minor improvements and corrections in the 3d views
- restored the missing curve style page in Windows in the fast graph settings

flow5 v7.01_beta_11 June 29th 2020

General
- the format of the .fl5 project file has been modified; NEWLY SAVED FILES WILL NOT BE READABLE BY VERSIONS OLDER THAN BETA_11
Modeling
- added an option to design a NURBS fuse to fit a set of control points; see here for detailed explanations
Meshing
- made more tweaks to the advancing front mesher to improve its robustness
- modified the triangle connections at the thick wing tips to improve symmetricity in the case of fins
- modified the triangle connections at the central section to improve Cp calculations for triangular analyses; requires regeneration of the operating points
- corrected the connections of quad panels at surface tips to improve Cp evaluation in the case of 3d quad panel analysis
- added more check options and display helpers for quad meshes
Analysis
- modified the calculation of the pitching moment in the case of tri-linear analyses to use Cp values at nodes instead of an averaged Cp over the panel's area; see here for detailed explanations
- optimized for speed the construction of the RHS vectors using linear combinations; reduction of analysis times for t7 polars by 50%
- fixed non convergence issues of T6 polars using the tri-linear method
- hard-coded the position of the vortex and control point positions on the quad panels at 25% and 75% respectively to avoid unintentional mods when saving/loading settings
GUI
- modified the display of pressure forces in the case of trilinear polars to display the arrows at the nodes instead of at the panels' center
- corrected the horizontal flip view so that it is performed around the z-axis instead of the y-axis
- added an option to export 2d views to SVG files
- made the length of panel forces independent of the selected pressure unit
- added a context menu to the analysis range tables
- added an option to offset the origin of the background image in 2d views
- restored the Ctrl+C and Ctrl+V shortcuts in the tables
- added a check for point mass duplicates when exiting the plane inertia dialog
Other
- corrected mapping errors when importing plane analyses from legacy .xfl project files
- removed a crash bug when trying to change the active polar while running an analysis
- removed some occasional and minor memory leaks

flow5 v7.01_beta_10 June 21st 2020

Analysis
- corrected an error in the calculation of the stability derivative Xq - minor impact on longitudinal modes
- reduced the default value of the vortex core radius from 0.5mm to 0.05mm; the former value could create issues with small mesh elements; the value can be modified in the 3d analysis settings
GUI
- fixed issues with the 3d display of spanwise lift, drag and downwash

flow5 v7.01.beta_09 June 14th 2020

General
- added full compiler optimizations to improve execution speeds
Design
- added an option to set the number of panels at the wing tips; recommendation is n>1; use n=1 to maintain compatibility with earlier versions
Analysis
- improved the calculation of the induced drag which is now evaluated at half the wake's length; this prevents wake end effects which could cause apparent negative drag on the elevator; see here for detailed explanations
- improved the calculation algorithm for Cp coefficients in the case of the tri-linear method;
  errors vs. theoretical results are now 0.25% for the sphere and 0.9% for the cylinder for a 5000 size mesh; project files and details: Validation.html
- added an option to run analyses using multiple aoa or ctrl ranges
- added a batch analysis mode using the xml analysis files
- added automatic update of inertia ranges when running a T6 or T7 analysis if auto-inertia is activated
- fixed the bug which caused the neutral point position not to be added to the polar variable in stability analyses
- corrected a minor error in the geometric construction of node normals on thin surfaces; very minor impact on results in the case of tri-linear analyses
Scripts
- added handling of multiple ranges for the aoa and the control parameter; see the updated template.
- corrected a bug which caused the script to use CUSTOM reference dimensions even if PROJECTED or PLANFORM were specified in the polar xml file
- added missing fields Include_Other_Wing_Area, Adjusted_Velocity, Delta_n in the Xml analysis files; export analyses to get updated templates for each type.
- corrected a write error when exporting operating ranges of control polars to xml
Sail analysis module
- corrected the moment variable in Boat polar plots which had a 2x factor in excess
- corrected various minor issues with the 3d display
Post-processing
- restored the display of LLT operating points in wing graphs
- corrected minor GUI issues related to T3 speed polars
- corrected the display of the arrow representing the global force for negative lifts
- corrected the display of the location of the thick arrow representing the global force
Other
- added an option to plot a fast graph with custom data in a floating window (Ctrl+G) - EXPERIMENTAL
- added multithreading to some lengthy geometry construction tasks
- fixed occasional crash bugs linked to async repaint of the main 3d view
- added an option to read custom line colours from the colorlist.txt file located in the application's directory; this file must hold 72 colours
- improved again the dark mode settings

flow5 v7.01.beta_08 May 17th 2020

General

the format of the .fl5 project file has been modified; NEWLY SAVED FILES WILL NOT BE READABLE BY VERSIONS OLDER THAN BETA_08
the binary package for Windows has been compiled with msvc2019 instead of msvc2017; as a consequence, it may be necessary to run once the vc_redist.x64.exe executable if Microsoft's redistributable Visual C++ libraries are not installed on the system; this package can also be downloaded from Microsoft.
the binary packages of this version makes use of a new licensing system

Design

added alternatives to SINE and COSINE distributions for less violent panel bunching - experimental
corrected some minor issues when designing a foil from 1 or 2 splines

Meshing
- improved the advancing front mesher to avoid divergences in special cases of coincident vertices
- added automatic removal of null triangles which could hinder the analysis
Analysis

corrected an error in VLM2 analysis which caused asymmetric results. Only apparent in the case of low spanwise panel densities and in presence of sweep; impacts the results.
corrected the construction of wake panels in the case of control polars; were aligned with the aoa direction, whereas they should be aligned with the x-axis since the geometry is rotated; impacts the results.
activated the ground effect option for Dirichlet BC, i.e. cases of thick surfaces and fuselage
parallelized the computation of velocity vectors to reduce analysis times
corrected a crash bug when running control polars

Scripts

restored the option to load foil .dat files
made the search for .dat and .plr files recursive starting from the specified directories
added an option to load XFoil-generated polar files in text format when running a script
corrected a crash bug when requesting the export of all plane polars using either the GUI command or when running a script
corrected a bug which caused xml plane files not to be found when running a script
removed the obsolete legacy option Ignore_Body_Panels in the analysis .xml files and replaced it with Include_Fuse_Moments. Export an analysis to xml to get an updated template.

3d views

added sliders to fine-tune the 3d viewpoint
added an option to display the ground surface in the 3d view if the ground effect is active
added an option to use 2-colours based gradients for 3d colour maps
added an option to display contour lines on top of the colour map for tri-linear operating points
fixed the updates of the aoa and other values in the 3d view animation
restored the highlighting of the selected frame in the fuse edition view
added an option for model autorotation around the z axis
fixed various issues with light settings

Pre-processing

modified the sorting of plane polars using the plane as first index and the polar name as second index; this displays the polars names in alphabetical order in the in-graph legend

Post-processing

fixed the slow computation times of streamlines along y-lines and z-lines
corrected minor errors in the streamline algorithm
added an option to display forces on parts in the 3d view; represented as arrows with origin at the 1/4 chord point
corrected the output of forces on parts in the Operating Point properties box
added the local strip forces to the operating point graphs
corrected the plot of the Fx_FF variable to the polar graphs, so that it includes the viscous drag and to give it in wind axes rather than body axes
corrected the plot of circulations in Operating Point graphs for VLM analyses

implemented automatic copy of export file paths to the clipboard for quick insertion in external applications
added an option to antialiase graph plots - active by default
added an option to antialiase all 2d views - active by default
added an option to export graphs to SVG images
implemented curve deselection when clicking elsewhere than on a graph curve
added new options for curve symbols - messes up existing cross symbols in legacy project files
added a checkbox to toggle visibility of all curves
multithreaded more tasks for increased UI responsiveness
improved dark mode settings

Sail design and analysis

corrected minor interface issues in the 2d and 3d views

OpenGL

improved the options to test OpenGL contexts
fixed the inoperative save of OpenGL settings
improved antialiasing by multisampling for contexts >= 3.3
removed unnecessary tasks when closing the app to speed up the exit process

removed a few more minor bugs

flow5 v7.01.beta_07 March 25th 2020

modified the format of the .fl5 project file; NEWLY SAVED FILES WILL NOT BE READABLE BY VERSIONS OLDER THAN BETA_07
corrected minor bugs in the algorithm used to approximate a foil with a cubic spline
modified the calculation method of angular derivatives for triangle methods - slight impact on results
corrected an error in the calculation of the lateral stability derivatives Xq, Yr, Lr, Nr
modified the calculation method of control derivatives: the angular position of the control surface is now set independently of the gain.
corrected an error in the calculation of control derivatives due to a confusion between degrees and radians
corrected the calculation of the vertical tail volume in the case of double fins - info only, no influence on results
removed a few more minor bugs

flow5 v7.01.beta_06 February 19th 2020

modified the format of the .fl5 project file; NEWLY SAVED FILES WILL NOT BE READABLE BY VERSIONS OLDER THAN BETA_06
modified the input/output of the script files:
- all output files are created directly in the specified output directory instead of a subdirectory; it is up to the user to specify or not the sub-dir in the output path
- plane polars output files take the name of the polar and are exported into a subdirectory with the plane's name
- the log file takes the name of the project file with the .log extension
- scripting in Windows now accepts the backslash in directory paths
improved the algorithm to build the intersection of wings and fuselage
removed the SECONDWING option; all second wings are replaced with OTHERWING
added an option to include the area of OTHERWINGs in the polar's reference area
added an option to plot streamlines in a vertical plane
modified the streamline generation algorithm for improved smoothness and for compatibility with future vortex particle wake
fixed the error which corrupted the export of planes as project files
restored the option to check for application updates
modified the SVG export format for increased versatility
added the vertical tail volume T_v=(S_fin x l_fin)/(S_wing x span_wing) to the output of the plane's properties
removed a few more minor bugs

flow5 v7.01.beta_05 January 14th 2020

removed the hard-coded limit on the max. number of operating points/run; added an option tto set this limit in the 3d analysis settings.
corrected a bug in glide polars which caused the calculated balanced speed to depend on aoa increment
corrected the stability analysis of planes with fuselages to take into account the option to exclude the contribution of fuselage panel forces to moments
corrected the length of the first streamline segment when applying an offset in the streamwise direction
restored the option available in xflr5 to store operating points even if the viscous interpolation is unsuccessful
restored the bending moment variable in the operating point graphs
improved the construction of the geometry of wings with a center gap
added an experimental option to export foil geometries to SVG files; export options can be set in the preferences
added a menu entry to load a legacy xflr5 project file
fixed occasional crash bugs when loading legacy xflr5 project files
fixed the crash bug when trying to display surface velocities in the 3d view
fixed more issues with macOS dark mode
removed a few more minor bugs

flow5 v7.01.beta_04 January 4th 2020

modified the calculation of induced drag in the case of triangle analyses by averaging the downwash over the trailing panel's width instead of using the value at mid-panel; this improves the accuracy of the predictions in case of high velocity and pressure gradients, for instance where the wings connect to the fuselage
corrected the error in the calculation of the fuselage form factor
corrected the variables Fuselage Drag and Fuselage Drag Coefficient in the polar graphs
added an option in the T1 & T2 analyses to interpolate viscous properties from Cl rather than Alpha, i.e. using the xflr5 method
added the effective angle of attack defined in the Ting & Chaparro report to the list of operating point graph variables
added the strip circulation to the list of operating point graph variables
corrected a bug which prevented the saving of modifications of the fuselage geometry after edition
corrected the algorithm to set a TE gap in the case of non-unit foil lengths
more tweaks added to make the triangle mesher more robust
fixed buffer overflow issues in the 3d display of streamlines
added an option to paint streamlines using the wing's colour
fixed some colour issues for macOS dark mode
removed a few more minor bugs

flow5 v7.01.beta_03 December 20th 2019

fixed the bug which caused the triangulation to disappear after a rotation action in the STL fuselage view
fixed a bug which caused the triangular mesh not to be generated after the import of an STL file
fixed a crash bug when importing a STEP file with undefined local surface normals
added foil name display as tooltip when hovered over in the foil design view
improved the robustness of the algorithm to modify a foil's TE gap
updated the mac package with the missing MKL libraries for mac pro configurations
added OpenGL shader logging to trace file
forced the use of deprecated functions and v120 style shaders if the requested version of the OpenGL context is <3.3
fixed some colour issues for macOS dark mode
removed a few more minor bugs

flow5 v7.01.beta_02 December 1st 2019 - First public release

implemented the fix for xflr5 bug report #147
restored some missing shortcuts in the foil view
corrected the display of plane streamlines with ground effect included
improved the management of overlaid curves in graphs
removed a few more bugs

flow5 v7.01.beta_01 November 24th 2019

added an option to import and overlay external curves in graphs
added an option to import plane polars and their data from an external source
removed a few bugs

flow5 v7.01.alpha_03 November 13th 2019

activated the advancing front mesher and deprecated the p-space mesher
optimized for speed the lengthiest tasks of the display and of the analysis
added an option to display the free edges of the triangle mesh
added thickness representation to the geometry shader for OpenGL 3.3+
corrected minor errors in the calculation of stability and control derivatives
converted sail forces from wind axes to geometric axes, which makes more sense for boats
added automatic unit scaling to meters when importing a STEP file
added an option to import and overlay external curves in graphs
added an option to import plane polars and their data from an external source
removed a few bugs

flow5 v7.01.alpha_02 October 15th 2019

implemented glide polars for xflr5 request 141
added wing design parameters to control polars
set a temporary back-end project file instead of the sync project
removed a few bugs

flow5 v7.01.alpha_01 September 28th 2019

enabled multithreading of the MKL routines on Windows and macOS
restored the signal connections between docked and floating graphs
restored the activation of plane polars when clicking curves in the polar graphs
added an option to import .plr files from the menu
added a menu link to the release notes
activated the link to update checks
removed a few crash bugs

flow5 v7.01.alpha_00 September 16th 2019 - Changes vs. xflr5 v6.47

Analysis
- implementation of 3d Galerkin triangular panel method using uniform doublet densities
- addition of a linear panel methods for increased accuracy
- generalization of multithreading for relevant tasks
- addition of a viscous loop for control polars
- addition of control polars
- addition of scripting capability
- addition of the INTEL MKL fast matrix solvers
- addition of a fuselage drag model
- use of OCCT to export bodies to STEP or IGES format
- use of OCCT to export wings to STEP or IGES format
- use of OCCT for inertia properties
- removal of the hardcoded limit on the number of wings
- addition of the capability for standalone body analyses
- addition of the capability for multi body analyses
- addition of forces and moments acting on each of the plane's parts to the polar graphs

GUI
- customizable default line width for all curves
- pickable Cp values in the 3d views
- addition of copy/paste capability in tableviews
- import/export of inertia data from/to clipboard
- export of object data to the clipboard
- export of graph data to the clipboard in spreadsheet format
- new simplified and more intuitive fuse and plane edition forms
- improved plane, wing and fuse design interfaces, with 3d views
- addition of 3d views in the design dlg boxes
- capability to open the 3d view in a separate window
- capability to open graphs in separate windows
- interpolated cubic spline and extrapolated BSpline for foil design and retro-engineering
- customizable automatic format for polar names
- selective x-y zoom in graphs
- selectable and highlightable curves in graphs and legends
- addition of a secondary vertical axis in graphs
- storage of log files for each analysis in a user defined directory

Sail7 merge
- Addition of wing sails
- Removal of SailCut type sails
- Removal of hulls from the analysis

Code
- removed all hard-coded limits in the 3d analysis module
- huge code overhaul for improved stability and portability

Features removed
1. Tilt. Geometry: was an experimental feature which generated more problems than it fixed
2. textures - fun feature, but too much overhead work to maintain in flow5