how to calculate the time step size and flow courant Number

sanjiiv · June 2, 2016, 22:25

Hi,
please tell me how to calculate the time step size for differrent problem in transient analyses.
And how to calculate the courant number for coupled solver,what is the use of fixing the coupled solver, and its use in multiphase cavitation analyses.

Thanks,

Sparow89 · June 6, 2016, 13:04

What kind of transient simulation are you running? If you are expecting a frequency response my general rule for calculating time step size is to take the inverse of the frequency (the period) and divide it by 20 for the maximum time step. This will give you twenty steps per period and wouldn't be a bad starting point. Depending on how the run goes you may need to decrease your time step further. I am fairly new to CFD so if anyone has a better method please correct me.

June 2, 2016, 22:25	how to calculate the time step size and flow courant Number	#1
sanjiiv New Member sanjeev kumar.m Join Date: May 2016 Posts: 13 Rep Power: 10	Hi, please tell me how to calculate the time step size for differrent problem in transient analyses. And how to calculate the courant number for coupled solver,what is the use of fixing the coupled solver, and its use in multiphase cavitation analyses. Thanks,

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June 6, 2016, 13:04		#2
Sparow89 New Member Stephen Join Date: Jun 2016 Posts: 8 Rep Power: 9	What kind of transient simulation are you running? If you are expecting a frequency response my general rule for calculating time step size is to take the inverse of the frequency (the period) and divide it by 20 for the maximum time step. This will give you twenty steps per period and wouldn't be a bad starting point. Depending on how the run goes you may need to decrease your time step further. I am fairly new to CFD so if anyone has a better method please correct me.