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-   -   Too many VOF sub-timesteps problem (http://www.cfd-online.com/Forums/fluent/45988-too-many-vof-sub-timesteps-problem.html)

wanghong September 10, 2007 22:02

Too many VOF sub-timesteps problem
 
hi,all

i am simulationg a free surface movement using VOF.when the mass flux of mass inlet is defined and time step is 0.002s,my computer tell me: "Updating solution at time level N... Error: Too many (3760548593) VOF sub-timesteps. The velocity field is probably diverging. Please check the solution, and reduce the time-step if necessary. Error Object: ()"

when time-step is 0.2s,error is following: "Updating solution at time level N... Error: Too many (274569734) VOF sub-timesteps. The velocity field is probably diverging. Please check the solution, and reduce the time-step if necessary. Error Object: ()". why? how to do it?


garima chaudhary September 11, 2007 01:38

Re: Too many VOF sub-timesteps problem
 
I think u shud try with timp step of .000002 and then gradually reduce n keep no of iteration s per time step at first to 50 and also remove any convergence criteria.and then gardually decrease time step size and then max no of iteratiuon per time step to 20 and then enable convergence criteria

wanghong September 11, 2007 02:48

Re: Too many VOF sub-timesteps problem
 
i try it using 0.00002,but my computer rell me:"error:floating point error:invalid number. why? wanghongbjut@yahoo.com.cn


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