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Average of Expressions in Transient Run for Parameter Study

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Old   August 7, 2012, 04:55
Default Average of Expressions in Transient Run for Parameter Study
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Hi there,

I am currently working in Workbench and am setting up a parameter study with my own custom expressions being used for inlet and outlet parameters. I am able to obtain data and create the graph in Workbench when varying an inlet condition in a steady state run as it takes the final value of each outlet parameters.

However, I am looking to use the same procedure for a transient run. This is clearly more difficult as my output expressions are more or less sinusoidal. Is there any way of taking an average of the output parameter expressions over the simulation timesteps (even better, the last 25% of them) in the transient run in order to create the automated tables and graphs in workbench?

Any info would be great. Cheers.
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Old   August 7, 2012, 05:34
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Yes, what you are looking for is possible. It has to be set in CFX-PRE.

In CFX-Pre, under "output control tab", you can find "Trn Stats" and under that option, you can find the average option for variables.


And if you would like to have an average value of a particle variable at a particular location, you need to create an expression and a variable. For ex. to obtain an avergae value of torque of a blade, the following steps have to be followed:
  1. Create an expression in CFX-Pre for torque, for ex: if your axis of rotation in the z-axis: torque_z()@blade
  2. Create an additional variable with Type=Unspecified, Units=[N m], Tensor Type = Scalar
  3. Include the additional variable in your domain (under the Fluid Models tab), and set its value to be the expression-(algebraic equation)
  4. Now when you create a Transient Statistics object you will be able to pick the Additional Variable from the list of variables. You can also choose the start and end averaging time.
All the best
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