time-averaging transient results
 

Hello all!

I've been trying to search for a method in Star to time-average transient results for unsteady flows. I went through the archives and still reading after a few hours. Maybe this has been explained before but if you don't mind, kindly tell me how do this time-averaging of transient results this time. Is this available in GUI? If not, do tell.

Re: time-averaging transient results
 

This is an example of prostar macro which I got from Paco who works for the support team in Nürnberg.


The example I was working with had 107 time steps (beginning
from
iteration 2 and increments of 2):

!First loading the pstt file!
trload,druck.pstt,nomvgr,,c
store,iter,2
!We could equally use the command getc, but if one does so,
all the postregisters are cleared.
oper, getc, su, 1
oper, getc, sv, 2
oper, getc, sw, 3
!Postregisters 1 to 3 are devoted to stored velocity
components (in this example). We
!then use postregisters 4 to 6 to store the sum of the
different iterations.
oper, copy, 1, 4
oper, copy, 2, 5
oper, copy, 3, 6
!Here we begin the loop for reading the remaining of
iterations
*define, noexe
*set, increm, 2, 2
store, iter, increm
oper, getc, su, 1
oper, getc, sv, 2
oper, getc, sw, 3
oper, add, 1, 4, 4
oper, add, 2, 5, 5
oper, add, 3, 6, 6
*end
*loop, 1, 107, 1
!In our example the number of time steps stored were 107
oper, sdiv, 107, 4, 4
oper, sdiv, 107, 5, 5
oper, sdiv, 107, 6, 6
oper, inverse, 4, 4
oper, inverse, 5, 5
oper, inverse, 6, 6

Re: time-averaging transient results
 

Thank you very much for your prompt response. I really needed something like this urgently.

I will modify this macro and inform you of my progress. I suppose the end-product of this macro is one post file? Can I save it with a different name?

Re: time-averaging transient results
 

It may be possible to activate the les averaging option (*.lesc files) for your case. I know you can do this with DES in 315.

I am not sure of the exact process, but I would say

Copy your old problem file

Turn on the les model with averaging and write the problem file (you may get some warnings regarding discretisation etc.).

Check the differences, I suspect one of them will be the flag to activate averaging. You will have to make a edit by hand of the problem file for every case you want to do averaging on.

Try these settings on a small model.

It is worth a try.

Steve

Re: time-averaging transient results
 

Interesting! Will try! At the moment too much work too little time...

Thanks for the idea!

Re: time-averaging transient results
 

you can do the avereging in the postdat soubroutine and compute any variable you want!