Plot output parameter’s oscillation

Pierre1 · March 21, 2015, 04:31

When I model cases with boundary layer separation, the output parameters always oscillate with iterations. That is normal and usually can’t be avoided easily. When I run a large number of simulations automatically, the simulations just can be set to run all automatically and only output parameters values without oscillation information can be given and listed automatically as well. But in this case, I won’t know whether oscillations happen in any of the simulations I just run and how strong the numerical oscillations are.

I once used Numeca Fine Turbo to do turbomachinery simulations. It could plot the oscillations of each design point automatically which brings huge convenience.

I’m wondering could CFX or Fluent also do that?

Thomas MADELEINE · March 23, 2015, 09:25

I have heard during a Webinar that CFX v16 can separate the oscillation of some parameters for turbomachinery.

If you want to plot the oscillation or the average of a variable you can create a expression that will catch it and plot it at the end.

to create a expression that will be implemented at each timestep you have to define an additional variable (AV) and link it to your expression.

March 21, 2015, 04:31	Plot output parameter’s oscillation	#1
Pierre1 Member Pierre Join Date: Mar 2015 Posts: 37 Rep Power: 11	When I model cases with boundary layer separation, the output parameters always oscillate with iterations. That is normal and usually can’t be avoided easily. When I run a large number of simulations automatically, the simulations just can be set to run all automatically and only output parameters values without oscillation information can be given and listed automatically as well. But in this case, I won’t know whether oscillations happen in any of the simulations I just run and how strong the numerical oscillations are. I once used Numeca Fine Turbo to do turbomachinery simulations. It could plot the oscillations of each design point automatically which brings huge convenience. I’m wondering could CFX or Fluent also do that?

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March 23, 2015, 09:25		#2
Thomas MADELEINE Senior Member Thomas MADELEINE Join Date: Oct 2014 Posts: 126 Rep Power: 11	I have heard during a Webinar that CFX v16 can separate the oscillation of some parameters for turbomachinery. If you want to plot the oscillation or the average of a variable you can create a expression that will catch it and plot it at the end. to create a expression that will be implemented at each timestep you have to define an additional variable (AV) and link it to your expression.