About flow5

To put it simply, flow5 is the next version of xflr5.

As of September 2019, xflr5 v6 has reached a certain degree of maturity in terms of functionality and stability following a 15 year plus effort that has been made possible thanks to your continued support and feedback.

Although there is still plenty of room to continue development, the latest improvements have only been incremental, with the introduction of most new features having been pushed back. The reason behind this delay is the difficulty of implementing new features given the poor state of the source code. This is the consequence of the application’s long development history, with new features having been added on top of existing ones.

So, some time ago, I decided to take the time to clean up the code and rewrite it in OOP style, with benefits expected in program stability and simplification for the next development phases. The result is an almost new application, where some 75% of the source code has been rewritten. From the outside, the application looks similar but under the hood it is significantly different. As a side benefit, this code refactoring has been an opportunity to merge it with sail7.

To mark these changes, the new version takes the name “flow5”.

This has enabled the implementation of a bunch of new features. Significant improvements have been added both to the UI and to the analysis engines. Among other things, there is a more intuitive user interface, additional interactive graphs, two new panel methods based on uniform and linear triangular Galerkin formulations, a greater versatility for plane design, the possibility (at last!) to properly analyse planes with fuselages, a scripting capability, interfaces to CAD software using standard STEP, IGES, and STL formats, reduced analysis times with the help of Intel’s MKL® library and with the extensive use of multi-threading, the possibility of meshes of finer sizes and increased number of freedom, and so on.

After considerable preliminary testing, flow5 has now been deemed to be stable enough to be released in alpha mode. The idea is to start collecting feedback on bugs and requests for features and improvements that will set the direction for the next development phase.

A very important point to note is that XFoil is not included in flow5.
It would have been great to keep it in, however, unfortunately, flow5’s closed-source approach is not compatible with XFoil’s GPL licence. flow5 is therefore a 3d oriented application. While it does provide options to design and modify airfoils, it doesn’t include any foil analysis capability. However, since airfoil viscous information is still required for the 3d-analysis, an in-app interface between flow5 and xflr5 has been implemented to make the exchange of airfoil data as seamless as possible.

Although flow5 is now usable for 3d design and analysis, with a stable UI, the amount of work which remains on the to-do list is considerable and beyond what can be reasonably achieved as a hobby. Check out the development plan to learn more.

For this reason and after some consideration, I have decided to request your financial support to continue the program’s development. This can be viewed as a crowdfunding request, except that the product is already available, even if only in beta status.

Again, thanks to every one of you for your continuous support. flow5’s existence today is due in great part to the overwhelming positive support and feedback you have given over time to xflr5.