Along which direction is the lift coefficient

djan · April 22, 2012, 16:40

Hi im doing a 2D CFD case for a NACA foil pitching and heaving. Was just wondering if the lift coefficient given by fluent is normal to the inlet flow or normal to the moving foil at that time instant. Thank you.

LuckyTran · April 22, 2012, 19:32

Quote:

Originally Posted by djan

Hi im doing a 2D CFD case for a NACA foil pitching and heaving. Was just wondering if the lift coefficient given by fluent is normal to the inlet flow or normal to the moving foil at that time instant. Thank you.

The user inputs for Drag and Lift coefficient will ask you to input the force vector. The drag and lift coefficients are then calculated with respect to this inputted vector regardless of what the inflow conditions are.

djan · April 23, 2012, 20:32

Thank you for replying. So if i input to calculate lift for the foil, it will be normal to the foil and and not respect to the x and y velocities in the global coordinate at that instant. Hope this is what you mean.

LuckyTran · April 23, 2012, 23:29

Quote:

Originally Posted by djan

Thank you for replying. So if i input to calculate lift for the foil, it will be normal to the foil and and not respect to the x and y velocities in the global coordinate at that instant. Hope this is what you mean.

No. Read my words again. It will calculate it with respect to the vector that you input.

It does not care what the global x, y, or local surface normal is.

April 22, 2012, 16:40	Along which direction is the lift coefficient	#1
djan New Member Join Date: Feb 2012 Posts: 4 Rep Power: 14	Hi im doing a 2D CFD case for a NACA foil pitching and heaving. Was just wondering if the lift coefficient given by fluent is normal to the inlet flow or normal to the moving foil at that time instant. Thank you.

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April 23, 2012, 20:32		#3
djan New Member Join Date: Feb 2012 Posts: 4 Rep Power: 14	Thank you for replying. So if i input to calculate lift for the foil, it will be normal to the foil and and not respect to the x and y velocities in the global coordinate at that instant. Hope this is what you mean.