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