[gsCFD91]

Hello everyone,
I'm new in this forum, I hope you can help me!

I'm trying to test the geometry of a flow stabilizer in an hydraulic system using CFX. It's a simple single-phase and steady state analysis with water as fluid. The purpose of the flow stabilizer is to smooth out turbulence which is generated by an hydraulic elbow: the water enters from the elbow and then passes through a series of simple hydraulic devices. Finally it exits from a nozzle. My idea is to test different geometries of the stabilizer by monitoring the transverse velocity components at the outlet section of the nozzle: for example if the nozzle axis is placed along the y axis, I would monitor the maximum and the minimum velocity along x axis and z axis: the lower these values, the best is the geometry of flow stabilizer.

Using the same geometry, boundary conditions, turbulence model and average mesh size I get completely different results if I run a simulation with Solidworks flow simulation too.

For example:
min x velocity (CFX) --> -0.328 m/s;
min x velocity (SWX) --> -0.081 m/s.

I also plotted a 3D profile of transverse velocity components in these two cases: they are different!
My question is: Is this situation due to the difference between the solvers?

Thanks to all.

[ghorrocks]

Different solvers will have different sensitivity to mesh size. So the same mesh on different solvers is not necessarily meaningful. You need to do a mesh sensitivity check on each solver to check that your results are on a mesh fine enough to be meaningful. If the mesh is too coarse then the results could be anything and you might as well be comparing random numbers.

While you are at it, you should check the convergence tolerance for each solver as well. Again, if it is not converged the results are meaningless.

[gsCFD91]

Thank you so much for help! I will proceed doing a mesh sensitivity check for both solvers.