Drag force calculation using URANS

Maffei · September 13, 2017, 13:26

Hi,

I'm working in my end-of-graduation-course paper, it's ,briefly speaking, a study about the flow behavior under a NACA0015 with a flap and gurney flap. Becouse of the size mesh and turbulence model, a steady state simulation do not converge (residual target 1e-6), so I used URANS. I know how to calculate the average of variables, but, here is my question, can I calculate the average of drag force?

ghorrocks · September 13, 2017, 20:06

If I was doing this I would:

* Make a monitor point which had the drag force.
* Run the simulation
* make a solver monitor to display the drag force for each time step. Make the X axis time, not iteration number
* Export the data to a csv file
* Load the CSV into excel, matlab, python or whatever you use for mathematics and calculate time averages or whatever you want.

Maffei · September 16, 2017, 21:48

thanks for answering,

I need to do the average of drag force acting under the airfoil,I think that this resolution will not work. Am I correct?

ghorrocks · September 17, 2017, 22:01

You think the Resolution of what will not work?

Maffei · September 18, 2017, 01:22

no, my question is whether I can set up the bondary at CFX pre.

ghorrocks · September 18, 2017, 01:38

I do not understand your question. Can you say what your question is again, but more clearly?

September 13, 2017, 13:26	Drag force calculation using URANS	#1
Maffei New Member Felipe Silva Maffei Join Date: Dec 2015 Posts: 12 Rep Power: 10	Hi, I'm working in my end-of-graduation-course paper, it's ,briefly speaking, a study about the flow behavior under a NACA0015 with a flap and gurney flap. Becouse of the size mesh and turbulence model, a steady state simulation do not converge (residual target 1e-6), so I used URANS. I know how to calculate the average of variables, but, here is my question, can I calculate the average of drag force? Last edited by Maffei; September 13, 2017 at 13:28. Reason: erro in title

September 13, 2017, 20:06		#2
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,854 Rep Power: 144	If I was doing this I would: * Make a monitor point which had the drag force. * Run the simulation * make a solver monitor to display the drag force for each time step. Make the X axis time, not iteration number * Export the data to a csv file * Load the CSV into excel, matlab, python or whatever you use for mathematics and calculate time averages or whatever you want. juliom likes this.

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September 16, 2017, 21:48		#3
Maffei New Member Felipe Silva Maffei Join Date: Dec 2015 Posts: 12 Rep Power: 10	thanks for answering, I need to do the average of drag force acting under the airfoil,I think that this resolution will not work. Am I correct?

September 17, 2017, 22:01		#4
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,854 Rep Power: 144	You think the Resolution of what will not work?

September 18, 2017, 01:22		#5
Maffei New Member Felipe Silva Maffei Join Date: Dec 2015 Posts: 12 Rep Power: 10	no, my question is whether I can set up the bondary at CFX pre.

September 18, 2017, 01:38		#6
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,854 Rep Power: 144	I do not understand your question. Can you say what your question is again, but more clearly?