Courant Nummber and Time Step VOF

doubtsincfd · June 29, 2011, 13:50

Why and how does OF change timestep and Courant number for every time level? Does the solver use max. Courant no value to calculate delta T? If yes, why does it vary the Courant number for each time level? Is there something different about automatic time step calculation for VOF? Fluent does have some different logic to calculate the time step.

akidess · June 30, 2011, 04:03

Yes, OpenFoam uses the maximum local Courant number to adjust the time step. OpenFoam does not change the Courant number. However, if your flow is varies with time, so will the Courant number.

For the code, see:
http://foam.sourceforge.net/docs/cpp/a03744_source.html

June 29, 2011, 13:50	Courant Nummber and Time Step VOF	#1
doubtsincfd Senior Member Join Date: Nov 2009 Location: Michigan Posts: 135 Rep Power: 16	Why and how does OF change timestep and Courant number for every time level? Does the solver use max. Courant no value to calculate delta T? If yes, why does it vary the Courant number for each time level? Is there something different about automatic time step calculation for VOF? Fluent does have some different logic to calculate the time step.

June 30, 2011, 04:03		#2
akidess Senior Member Anton Kidess Join Date: May 2009 Location: Germany Posts: 1,377 Rep Power: 29	Yes, OpenFoam uses the maximum local Courant number to adjust the time step. OpenFoam does not change the Courant number. However, if your flow is varies with time, so will the Courant number. For the code, see: http://foam.sourceforge.net/docs/cpp/a03744_source.html ShashiDeSilva likes this.