Why am I seeing weird, non-physical structures in my flow?

miratipmiratip Member Posts: 2

I set up my geometry (3d cube) and mesh using the Ansys workbench GUI. I then wrote the data to a case file. I am trying to run my simulation in batch mode using a journal file. I read in the case file, set up gravity, set up my boundary conditions, initialized the flow, and then ran the simulation. When I post-process my results I am seeing non-physical structures in my velocity and pressure fields. When I check the initial values of velocity and pressure, there are no non-physical structures and everything seems to be initialized properly at 0. I am attaching contour plots of the y-velocity (through 2 different slices in z) after 1 time step to illustrate what I mean by non-physical structures. The structures persist through all the time steps. Why is this happening?


Answers

  • RobRob UKPosts: 11,730Forum Coordinator

    As staff are not permitted to open attachments I can only guess that the solution isn't converged, alternatively there's a boundary condition or other setting that's not correct.

  • miratipmiratip Posts: 5Member

    The solution is converging. Should I change my tolerances maybe? For my boundary conditions I set the bottom boundary as a wall and the other 5 as pressure outlets with zero gauge pressure. I am eventually planning to add a droplet to the flow to simulate a droplet falling under gravity and hitting the wall. Do these boundary conditions seem correct? I read in the documentation not to include hydrostatic pressure in the pressure outlet BC which is why I am setting the pressure outlet gauge pressure to zero at the 5 boundaries. Also, is there a way to show you my results without you needing to open an attachment? Thanks.

  • peteroznewmanpeteroznewman Posts: 12,786Member

    @miratip you can do a screen snapshot and do Ctrl-V to paste it into the reply to @Rob

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