NACA 0012 mach 0.5 6 degrees

papis · December 8, 2010, 13:30

HI,

I have a code that solves the viscous/inviscid cases.I am working on the validation of the code and i have seen a shock wave appearing at mach 0.5 at 6 degrees(inviscid case) but only in fine grids.The strange thing is that in coarse grids as well as in viscous cases the shock isn't there(cl ~0.75 in coarse grid ~0.669 in viscous cases).However when i use a fine grid to run the inviscid code a shock appears and the lift coefficient is around 0.85...

I know it's weird and i am looking for a bug for a while now but nothing came up.Has anyone here experienced anything like this?

papis · December 9, 2010, 12:27

It would help me much if somebody was able to run an inviscid naca0012 on a fine grid at mach 0.5 at a = 6 degrees and post the pressure coefficient.

Thanks again.

ignat · December 10, 2010, 03:38

Quote:

Originally Posted by papis

The strange thing is ...

This thing is not strange because all difference schemes have non-physical (artificial) viscosity depending on grid spacing. Your shock is weak and it smeared at coarse grid. It is natural phenomenon.

December 8, 2010, 13:30	NACA 0012 mach 0.5 6 degrees	#1
papis New Member Papis Join Date: Dec 2010 Posts: 25 Rep Power: 15	HI, I have a code that solves the viscous/inviscid cases.I am working on the validation of the code and i have seen a shock wave appearing at mach 0.5 at 6 degrees(inviscid case) but only in fine grids.The strange thing is that in coarse grids as well as in viscous cases the shock isn't there(cl ~0.75 in coarse grid ~0.669 in viscous cases).However when i use a fine grid to run the inviscid code a shock appears and the lift coefficient is around 0.85... I know it's weird and i am looking for a bug for a while now but nothing came up.Has anyone here experienced anything like this?

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December 9, 2010, 12:27		#2
papis New Member Papis Join Date: Dec 2010 Posts: 25 Rep Power: 15	It would help me much if somebody was able to run an inviscid naca0012 on a fine grid at mach 0.5 at a = 6 degrees and post the pressure coefficient. Thanks again.