Hello everyone, 

I have a recurrent problem when meshing with SnappyHexMesh: there are "holes" on some boundaries of my mesh (see picture). Do you know why this is happening? And what could I change to have a mesh that perfectly match with my geometry? I am working on a passage of a centrifugal compressor. 

Thank you in advance !

Alex 

Hi everybody, 

I ran a steady state + transient CFD simulation on a centrifugal compressor (with a k-omega SST model) and when post-processing the results and comparing the stationary part to the unsteady part of the calculation I have significantly different results. Indeed, the unsteady part shows a higher mass flow rate. This seems to be due to a higher flow speed and a...

Hello everybody, 

I am setting my first CFD transient simulation on a centrifugal compressor and I would like to know if you have any recommendations on the values of parameters like CFL number or PIMPLE algorithm settings. I assume that the default value of CFL number is relatively large (=20 hence >>1) because the PIMPLE algorithm is flexible and that's common to u...

Hello again, 

I was wondering also if boundary layers are mandatory to capture precisely the turbulence near the walls or if a good refinement can be satisfying? As soon as my geometry is getting complex, my boundary layers start to collapse at certain locations on the walls

I am using a k-omega SST model with a standard wall function, so my simulation should be quit...

Hello everyone,

I am currently trying to reduce my number of cells on my mesh and I was wondering how to implement and control an expansion ratio on TMESH? to have a coarse mesh that becomes thinner linearly along a pipe for example

Thanks

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