Fluids

Fluids

How to avoid wrong Velocity field?

    • schwaral
      Subscriber
    • Surya Deb
      Ansys Employee
      Hello, nIt is not very clear about the values here. Do you mean why you see a slight deviation in the max velocity at the corners near the inlet+symmetry?nHow does the mesh look like in those regions? Did you try to refine the mesh and see how it behaves?nWhat happens if you let it run for a few more timesteps? Do you see a more uniform profile?nRegards,nSuryann
    • schwaral
      Subscriber
      after some timesteps with constant velocity (5 m/s) (initialze with (0m/s) there is no deviation anymore, but in my case it is important, that the velocity is equal at every cell. nThe mesh has same cell size everywhere and the convergence is good. I think it is not due to mesh. I have seen this behavior also in my previous cases. There it did not matter. nThe problem I have: Next to the Inlet will be a porous media with uds.... the source term of this uds uses velocity component. When my velocity field is not correct, my source term is wrong calculated and it keeps the values from timestep to timestep in its brain. So even when the flow field becomes homogen after some Iterations, my UDS value in the porous media will stay wrong and be messed up more and more with time.And to make it more difficult. nI use a UDF for velocity-inlet. So the velocity changes with every timestep (But every cell should have during one timestep the same magnitude). SO always when the velocity Magnitude changes, I see this wrong velocity magnitude in the corner. I really have no idea what to do anymore :/. In my case 10 cells in higth. every cell a square of 0.001 by 0.001 mm. Same effect, when velocity is smaller (e.g. 0.1 m/s)n
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