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Wrong Power Coefficient

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Old   August 10, 2018, 11:07
Default Wrong Power Coefficient
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Manon Puech
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Hello,

I am currently doing a Msc Thesis and my subject is: Cavitation Modelling Using CFD of a Rotating Propeller.
The project is based on the Southmapton experiment and I am trying to have the power coefficient with simulation in order to validate the model.
Unfortunately the Cp obtained is not correct: I end up with a Cp=0.27 instead of 0.42 with a speed water of 1.73m/s and a pitch angle for the blade of 20.
The formulas used are detailed in the txt file.
I already tried to refine the mesh and change some parameters but it is still not showing good results.
The software used is Ansys CFX and if you want to take a look at the setup and boundary conditions you can see them on the txt file also.

If you have some ideas why the results are not good I would be glad to have them.

And thank you for the time you took to read this post

Have a good day!
Attached Files
File Type: txt CFX_001.txt (46.3 KB, 5 views)
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Old   August 11, 2018, 01:37
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Glenn Horrocks
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Have you read the FAQ on accuracy? https://www.cfd-online.com/Wiki/Ansy..._inaccurate.3F

Have you done a convergence criteria, mesh size and time step size sensitivity analysis?

Are you aware that cavitation modelling is very challenging and getting accurate results is not always possible? Cavitation models are not models where you should expect high accuracy.
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