Questions from the workshop
 

Hi Santiago,

Am posting the Questions over here as you asked me to.

Q1. What is the name of the variable in the code that keeps a track
of the total time. Where is it defined and used and where is it
incremented- that is : time = time + delta_time ?


Q2. If it is required to stop the simulation at a particular exact
time, it was suggested before to use the variable "UNST_TIME" in the
config file under unsteady simulation to do it. But the exit
conditions of the program are based on Ext_Iter or the residual
convergence. Then where does it have this condition of exiting based
on UNST_TIME mentioned in the code.


Q3. What if i want to do this for a steady problem. How to get solution for an
exact time?

Thanks again for the reply.

Unsteady simulations, Unsteady time
 

Q1. In the code we keep track of the total iteration variable ExtIter and increment it for each iteration. This is done in SU2_CFD.cpp file. And we keep track of the provided delta_time in in the config class and can obtain its value with the method GetDelta_UnstTime(). So we keep track of the total time by multiplying the ExtIter*delta_time. You can see this done in the function MeanFlowIteration in iteration_structure.cpp.

Q2. If you look at the end of the MeanFlowIteration function in iteration_structure.cpp you will see the UNST_TIME option being used. You can also always stop the simulation at an exact time by using the Ext_Iter stopping criteria (t = Ext_Iter*dt).

Q3. I’m not sure I fully understand this question, but I steady problem does not depend on time, so it doesn’t make sense to stop it before it has converged to a desired level of accuracy. To stop the steady problem you can also use Ext_Iter in addition to the residual convergence criteria.

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Best,
The SU2 team