[songyi719]

Hi, I am doing some car aerodynamic simulation by modifying DrivAerFastback tutorial.


It is a sim using simpleFoam and Rans k-w SST



I changed car model by one I have and increased mesh resolution


However, drag coefficient seemed to converge to ~800s, but started diverging near 900s~1000s. Lift coefficient didn't converge for whole time


So, I thought it may be solved when I increase total simulation time, so I increased max time to 5000s.


However, C_d repeated converging and diverging in such pattern. After few hundreds of seconds passed, it started diverging, return to converging solution, and repeat to diverge after another hundreds of seconds


Why would it show such strange pattern? I know that sim can diverge, but I never heard that simulation repeats to converge and diverge