Learning Forum

[mokhtarahmed448]

I try to simulate fluid flow and brine-seawater mixing in a rotary pressure exchanger using ansys fluent 2025 R2 native GPU solver. I use the realizable k-e turbulence model, species transport without reaction for mixing simulation, and compressible water as a material. when I start the initialization (standard or hybrid) , the error " ERROR except: an illegal memory access was encountered on rank 0 memory usage 0.503135/0.662375 GB in function: Cromwell::CWrapper::InstanceBase::Initialize, at Line: 135, File: E:\ADOAgent\_work\4\Cromwell\Cromwell\CFD\CWrapper\src\SolutionProcedure.cpp " appears, and the calculation fails. But when I don't solve species transport or set the water density as constant instead of compressible liquid, the calculation runs without problems. the error appears when using both species transport with compressible liquid.

[Rob]

Did you set the case up in the GPU solver or did you set up on CPU and transfer? Not all models and combinations of models are available on the GPU solver at present: what's available is changing with every release. 

[mokhtarahmed448]

 

I tried the both methods. In the first method, I set the case through the workbench and transfer it to the standard alone fluent activating native gpu solver. in the second method, I opened the  standard alone fluent, activated gpu solver, imported mesh file, and set the case. The same problem in both methods. As I know, both compressible liquid and species transport are supported in native gpu solver, but when I combine both, the problem appears.

 

[Rob]

Compressible liquid isn't listed, but that could be the manual being wrong too. Given the error I wonder if compressible liquid for mixtures lacks a memory allocation. Can you set two compressible liquid densities and weighted mixing for the mixture?

[mokhtarahmed448]

I set each liquid density as compressible liquid. For the mixture, I set the volume weighted mixing law option.