[aks2200]

Hello,

I doing my thesis work on flow over sphere. My is Re=10,000 and sphere diameter is 1D and Mach is 0.2(Schematic is shown below). I am using IDDES in OpenFOAM 2.4.x
I am new in CFD and OPenFOAM, I need to find how long I have to run my simulation so that I can get it's clear picture in power spectrum. I find out in form and website that I can calculate my time step size by using st number, ie,
st=1.98 (for Re=10,000)
then frequency is 13.6116 which gives me a time step per cycle of 0.07, this is way too small then what is see so far in forum, may be I am calculating it wrong. My velocity is 68.058 which I calculate using Mach number.
Can some one help me in figure out this, Do i need to give initial velocity of 68.058 in my simulation also. I have attached my case here as well

[aks2200]

Please help