Re=300 flow over a sphere

shailesh

Hi all,

I am simulating a Re=300 flow over a sphere. Acoording to the literature and previous numerical studies, wake at Re=300 is periodic and has shedded vortices..BUT i couldn't get any such periodicity...I read in some other papers..that at low reynolds numbers like..300..1000..flow is generally stable..and to start the vortex shedding..some perturbation has to be given..so I gave a perturbation..like multiplied the streamwise velocity in the upper half of sphere by 1.1 at some (only once) time step. Actually it seemed that it did have vortex shedding but only for some time..it couldnt be sustained and the flow is back to steady again..i am wondering what could be wrong..do i need to refine my grid more..??

regards shailesh