# Drag and lift coefficient for hydrofoil

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June 25, 2013, 21:47
Drag and lift coefficient for hydrofoil
#1
New Member

Lee,Dong Beom
Join Date: Apr 2013
Posts: 21
Rep Power: 5
Hello

I am studying oscillating hydrofoil in water.

I have used k-e model and the frequency and amplitude of hydrofoil are 1.25Hz and 1.0m.

Also I used PISO for solution method.
time step is 0.001s and number of time step is 800.

and when I checked the drag coefficient, the values are between 10000~-80000.

Originally, I have expected the value near 1.0.

I am wondering I have made some mistake in my model or the values are true?

Is there any one who could give me valuable comment?

Have a nice day all~
Attached Images
 boundary condition.jpg (91.1 KB, 17 views) colution method.JPG (60.4 KB, 14 views) drag coefficient.JPG (56.0 KB, 15 views) mesh.JPG (40.7 KB, 13 views) model.JPG (83.5 KB, 13 views)

 June 28, 2013, 16:27 Answer #2 Member     sadjad Join Date: Jan 2012 Posts: 70 Rep Power: 6 Hi mate, Did you revise "Referece Values"? __________________ ICEM, CFX and Fluent expert

July 2, 2013, 01:58
#3
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Lee,Dong Beom
Join Date: Apr 2013
Posts: 21
Rep Power: 5
Quote:
Hi

When I review my reference value, I can't find any strange point.
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 refer.JPG (23.4 KB, 7 views)

 July 2, 2013, 03:03 Answer #4 Member     sadjad Join Date: Jan 2012 Posts: 70 Rep Power: 6 It seems that you left default values and that's the problem. What indicated in Reference values are just used in calculation of some Dimensionless numbers such as Drag and Lift coefficients. As an example, for drag coefficient, you should revise Velocity, area and density. __________________ ICEM, CFX and Fluent expert

July 2, 2013, 03:17
#5
New Member

Lee,Dong Beom
Join Date: Apr 2013
Posts: 21
Rep Power: 5
Quote:
 Originally Posted by sadjad.s It seems that you left default values and that's the problem. What indicated in Reference values are just used in calculation of some Dimensionless numbers such as Drag and Lift coefficients. As an example, for drag coefficient, you should revise Velocity, area and density.

I will modify the reference value based on the my study.

Have a nice day~

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