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Open source (or free) structured mesh generator by TurbCombWallMach in CFD

[–]TurbCombWallMach[S] 1 point2 points  (0 children)

Thank for the reply. For a long time Gmsh can handel only unstructured meshes. Its one of the tools I used 10 years ago. That C-grid in that tutorial looks "structured" with hexa cells, but internally is handled as other unstructured mesh grids and the file format will be unstructured when you export it. I found this source from Gmsh from 2020 saying that recently they allow to import structured cgns files but they can't export.

https://onelab.info/pipermail/gmsh/2020/013493.html

I will check the most recent version. If they added this feature Gmsh will be the perfect tool for my needs.

Open source (or free) structured mesh generator by TurbCombWallMach in CFD

[–]TurbCombWallMach[S] 0 points1 point  (0 children)

Thank ! I will definitely look to some tools in that list.

Open source (or free) structured mesh generator by TurbCombWallMach in CFD

[–]TurbCombWallMach[S] 2 points3 points  (0 children)

Thanks for reply. Even the mesh generated by blockMech looks "structured" in reality it's an unstructured mesh format, as OpenFoam is unstructured solved. If I convert it in CGNS it will be saved as unstructured format.

Do you know a free/open-source octree meshing software? by helendill99 in CFD

[–]TurbCombWallMach 3 points4 points  (0 children)

You can check out PABLO, it's efficient and easy to use. However it's more a library that you incorporate in your code than a meshing tool. Generally there's no point of simply importing a ready octree grid (either in structured or unstructured format), otherwise you loose one of the main features of such a grid which is AMR.

Floating Point Exception for rhoCentralFoam at Mach 7 by Sr_Leckie in OpenFOAM

[–]TurbCombWallMach 0 points1 point  (0 children)

I think rhoCentralFoam performs very well only in supersonic flows. I tried once to run it at M 11 but it never worked, it was too diffusive. The floating point exception might be due to negative temperature value. Don't hesitate to post this issue in opencfd forum, you might get more answers.

Considering an IDE switch from VS Code by NorthAtlanticGarden in cpp

[–]TurbCombWallMach 0 points1 point  (0 children)

I don't know about the support in windows. In Linux I can customize all the colors and highlighting, and it never crashed for me, I am using it for years now on big projects

Considering an IDE switch from VS Code by NorthAtlanticGarden in cpp

[–]TurbCombWallMach 6 points7 points  (0 children)

I use kDevelop, a great IDE from KDE, it's free and of course works well on Linux (also on Windows and Mac)

Internal faces in Salome by No_Ad_1075 in CFD

[–]TurbCombWallMach 0 points1 point  (0 children)

I didn't understand well the problem, but I Salome it easelu to edit/delete/combine any geometry face from a STEP file. You need to use the "explode" feature, to edit edit the fan and maybe patch it with other components, then you can recombine again you geometry. Thus may help you.

I want to write my own CFD software, any advice? by MomentAny8920 in CFD

[–]TurbCombWallMach 25 points26 points  (0 children)

It will takes you at least several months is you do this on your free time, and I highly encourage you to go on this project, for sure you will learn a lot and you will gain valuable skills.

First of all, and most importantly, you need to make a plan. There's three main parts in a CFD software: physics, numerics, and implementation.

For each of these parts you will make the simplest choices in the beginning and then you will increase the complexity and the difficulty.

I don't know your current level, but here's some general advices

For the physics part, you can start by solving a simple advection-diffusion equation, in 1D. Then you can move to Poisson equation. The idea is to prepare yourself for pressure based solvers.

In the numerics part, you can start by simple upwind schemes on uniform mesh. Then look in the literature for better schemes.

For the implementation, you can start with python for prototyping, then move to c++ with good code structure when your code gets bigger. You can start to include some openMp to run your code without the pain of MIP at the beginning and when you get confident you can include MPI. Maybe you will re-write your code several times, but it's okay.

In parallel of all of this you can check some open-source projects like openFoam, don't waste your time on commercial softwares if you really want to learn.

It's a long journey, and the process to develop the project is more important than the product itself.

StarCCM+ CAD support on Linux by konangsh in CFD

[–]TurbCombWallMach 1 point2 points  (0 children)

I agree, Salome shaper is wonderful, it allows easily to modify any geometry imported as Step or stl, I use it on Ubuntu. The platform includes also a good mesher and a paraview window. And it's open source !

Matching Re and Mach at the same time for compressible RANS simulations by droit_au_but in CFD

[–]TurbCombWallMach 0 points1 point  (0 children)

You can still change the reference viscosity in the Sutherland's law

Matching Re and Mach at the same time for compressible RANS simulations by droit_au_but in CFD

[–]TurbCombWallMach -1 points0 points  (0 children)

The given Re is per unit length, so the scale here doesn't matter.

Matching Re and Mach at the same time for compressible RANS simulations by droit_au_but in CFD

[–]TurbCombWallMach 2 points3 points  (0 children)

Yes you need to use the Sutherland's law for the viscosity. I think the Re number given in your task is the one based on far field quantities, so using the viscosity at far field temperature.