Aadarsh Gejage asked 1 week ago
- Dear team I am using Flow 5 for my already using VTOL(baby shark Fox tech model) aircraft for validation of 3d panel method, I have successfully made 2D airfoil batch analysis with T1 in xflr5, and I have imported for both wing and tail, successfully made Wing with various station chord starting range from 295mm to 5 mm, as wing geometry you can see in the UAV image, for Tail geometry I have took two elevators and designed in such a way so that my inverted v tail will be formed for reference total geometry is attached, also for the fuselage I have imported from .step format having fuselage and two boom which are connected to the tail,
- Meshing is successfully done, as there is no open edge in fuselage body, and successfully joined mesh to wing and tail, I am ensuring there is no such open edge and wing and fuselage and tail successfully joined together,
- Now I am trying to do a Type 1 fixed V at 19m/s so I am getting all valid values of Lift and drag but Pressure coefficient along UAV showing CP=1 red color gradient through all UAV, also the range of color gradient at various alpha goes CP=1=red color to Cp=2759
=blue at negative side till 10 Angle of attack (as I am doing analysis from 0 to 10 AOA)
- So, there are two problem I am facing as of now, Problem a. one is Pressure Coefficient along UAV shows red color gradient seems CP=1 all over UAV and range of Cp is also 1 to 25000 for 1 to 10 AOA. b. My CPx (Centre of pressure along x direction) is showing in negative apart from UAV (seems invalid) as my origin of UAV start from pitot leading edge so my CG is at positive 600 and CPx is showing in other direction in negative side seems invalid, I have attached both images, CP and CPX problem image kindly revert me back wafting for the any kind of suggestion and reply.
- Since I was unable to add insert image, I have uploaded a link kindly open it all report has been uploaded in that link of google drive please download and check,
- https://drive.google.com/drive/folders/19PgcWSWInCFZPO9M5FGa-rMOseF7tOvb?usp=drive_link
1 Answers
Aadarsh Gejage answered 5 days ago
The Coefficient of problem has been solved, after changing the scale to -1 to 1.6 but, after disabling the option “include fuselage pressure force” and “wing tip pressure force” the problem still showing my XCP is out of geometry as my origin is at Global axis X=0 and my aircrafts origin is at leading edge i.e. pitot tube. so please tell me how I can solve this issue.
Hello,
Usually a uniform red color for Cp means that there is a local peak value somewhere. Change the scale to be [-1,-1] to identify where.
Local peak values often cannot be avoided because of the way that the pressures are calculated, however they are also not significant if located on the fuselage. Make sure that you de-activate the option “Include the contribution of fuselage pressure forces” in the analysis.
By definition, the location of the center of pressure will go to +/- inifinity when the lift tends towards 0.
André