Choosing the right timestep

shangzung · October 28, 2009, 08:52

Hello!

I simulate with sonicFoam a tube with different pressures in it and have problems with the timestep. Sometimes with a chosen timestep, simulation lasts about 1 hour before it fails (and the Courand number is over 1). Is there a way to determine, how large the Courand number will get or is there even a possibility to set the maximum Courand number, so that the timestep will vary?

akidess · October 28, 2009, 12:21

Yes, there is a possibility to specify a maximum Courant number. See how it's implemented in the interFoam solver (http://www.opencfd.co.uk/openfoam/doc/damBreak.html), or also threads in the forum (e.g. http://www.cfd-online.com/Forums/ope...co-number.html).

shangzung · October 29, 2009, 03:58

Thanks a lot! Like in the post of your link, I also has to add some #include statements into the solver I used (sonicFoam). Now it works great!

October 28, 2009, 08:52	Choosing the right timestep	#1
shangzung Member Dennis Rown Join Date: Oct 2009 Posts: 51 Rep Power: 17	Hello! I simulate with sonicFoam a tube with different pressures in it and have problems with the timestep. Sometimes with a chosen timestep, simulation lasts about 1 hour before it fails (and the Courand number is over 1). Is there a way to determine, how large the Courand number will get or is there even a possibility to set the maximum Courand number, so that the timestep will vary?

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October 28, 2009, 12:21		#2
akidess Senior Member Anton Kidess Join Date: May 2009 Location: Germany Posts: 1,377 Rep Power: 30	Yes, there is a possibility to specify a maximum Courant number. See how it's implemented in the interFoam solver (http://www.opencfd.co.uk/openfoam/doc/damBreak.html), or also threads in the forum (e.g. http://www.cfd-online.com/Forums/ope...co-number.html).

October 29, 2009, 03:58		#3
shangzung Member Dennis Rown Join Date: Oct 2009 Posts: 51 Rep Power: 17	Thanks a lot! Like in the post of your link, I also has to add some #include statements into the solver I used (sonicFoam). Now it works great!