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August 11, 2016, 09:16 |
pressure & friction drag co efficients
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#1 |
New Member
Abuzar Jamil
Join Date: Aug 2016
Posts: 4
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Hello, Can someone please tell me how to find Pressure drag coefficient and friction drag coefficient from the drag coefficient.
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August 11, 2016, 13:07 |
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#2 |
Senior Member
Join Date: Jul 2009
Posts: 357
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I am not aware of any technique for determining the pressure drag coefficient and friction drag coefficient from the total drag coefficient. Perhaps someone else might be more knowledgeable.
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August 11, 2016, 16:36 |
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#3 |
Senior Member
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The knovledge of the total drag coefiicient is not enough. You should know distribution of pressure (or the velocity gradients) on the surface of the object.
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August 12, 2016, 12:22 |
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#4 |
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Matt
Join Date: Aug 2014
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That's a loaded question. Can you explain where you are getting the drag coefficient from in the first place? Experiment, numerical solution, etc...?
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August 13, 2016, 01:25 |
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#5 |
New Member
Abuzar Jamil
Join Date: Aug 2016
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Thanks for the reply, I am simulating flow over an elliptical 2d cylinder using ansys(fluent) 14.5. I am getting the Drag coefficient from fluent using solve>monitors options.
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August 15, 2016, 09:31 |
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#6 |
Senior Member
Matt
Join Date: Aug 2014
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That is a much more concise question. Not being familiar with fluent, you may want to direct your question to the fluent forum to see the specifics but there should be an option to calculate pressure and viscous drag separately. If not, then you will need to extract the pressure and shear distributions on your body and integrate to get drag. You can see from the equations that you can separate out the pressure and shear terms and treat them independently. So take cp and calculate cn and ca, then take cf and calculate cn and ca. Then you can transform from normal/axial to lift drag (if you have an angle of attack) and get cd_pressure and cd_viscous.
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August 15, 2016, 13:26 |
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#7 | |
New Member
Abuzar Jamil
Join Date: Aug 2016
Posts: 4
Rep Power: 9 |
Quote:
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