Unsteady flow past cylinder for Re-50,100,150
 

Dear all,

I am about to write my own code to simulate flow past circular cylinder for Re-50,100,150. At these Re nos periodic vortex shedding can be observed.

the shedding frequency can be estimated based on the Strohaul Number(St), and it is good to have atleast 20 to 30 time stepping for each shedding cycle to capture the periodic vortex shedding.

But i have a doubt on how to set convergence criteria for each time stepping???
Is it required to converge to 10^-3 for each time stepping..

How to loop through the time???

How to calculate the residue.. whether is the magnitude of the difference between the left and right hand side of the equation or the difference between the velocity between each time step..

thanks
mecbe