help for Large eddy simulation

Randheer Yadav

hi, I am doing LES of submerged jet having the jet discharging into a rectangular tank. I have four doubts 1) how to decide the timestep for LES 2)if I start with a timestep 1e-05 then the simulation starts showing convergence for each time step for 20 iterations per time step(obviously it takes more iterations per time step for first few time steps. Can I increase the time step? 3) How to decide the no. of time steps (or how long) for which the simulation should be carried out. 4)How can we judge the coinvergence of a LES simulation and decide that our simulation is converged (Since the residue convergence is not always reliable). Thanks in advance, bye