Drag

ashishtbm · June 4, 2013, 09:20

I am simulating a 2D naca 0012 airfoil under invsid conditions but I am getting positive drag which should e ideally zero for inviscid case and streamline should turn at the trailing edge to up surface.
Even cylinder also ideally gives zero drag under inviscid conditions.
So, why fluent is giving pressure drag under inviscid conditions?

oj.bulmer · June 4, 2013, 10:43

Is it close to zero or larger. It will never be exactly zero.

OJ

ashishtbm · June 4, 2013, 13:53

my drag coefficient value at 4 degree angle of attack is 1.55e-3 and for cylinder it is around 1.2.
Does this value seems right for the inviscid case?
At higher angle of attack, flow even separates which should never occur for inviscid case.

June 4, 2013, 09:20	Drag	#1
ashishtbm New Member Ashish Kumar Join Date: May 2013 Posts: 4 Rep Power: 12	I am simulating a 2D naca 0012 airfoil under invsid conditions but I am getting positive drag which should e ideally zero for inviscid case and streamline should turn at the trailing edge to up surface. Even cylinder also ideally gives zero drag under inviscid conditions. So, why fluent is giving pressure drag under inviscid conditions?

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June 4, 2013, 10:43		#2
oj.bulmer Senior Member OJ Join Date: Apr 2012 Location: United Kindom Posts: 473 Rep Power: 20	Is it close to zero or larger. It will never be exactly zero. OJ

June 4, 2013, 13:53		#3
ashishtbm New Member Ashish Kumar Join Date: May 2013 Posts: 4 Rep Power: 12	my drag coefficient value at 4 degree angle of attack is 1.55e-3 and for cylinder it is around 1.2. Does this value seems right for the inviscid case? At higher angle of attack, flow even separates which should never occur for inviscid case.