update initial conditions every 10 iterations
 

Hi all,
I'm testing the whole operation curve of a hydraulic turbine, but the net head is highly dependent of the mass flow.
I want to update the Total Pressure inlet condition every 10 timesteps, to match the new losses.
The inlet condition would be something like this:
Ptotal,in = 115000[Pa] - k*Q^2
where k is a constant for losses and Q the massflow.

is it possible to do with cel expressions to update the boundary every 10 or more iterations?

Thank you in advance,
lindner

Yes, you can. However, you will have to do an expression for the current P rather than the total.
Just set the input to an expression and define the expression for current pressure.
CEL is quite easy to learn and there are quite a few specific examples in the tutorials provided with CFX, just watch the units.
Hope this helps.

Hi Martin,
Thanks for the quick answer! The cel expression is ok now, the only problem is to force the cfx to execute this expression every x timesteps (without fortran).
Im reading about user functions and user subroutine to find something about it.

Great, a simple iterative function should sort that. A bit of imagination and you will have it.