trying to solve 2d compressible euler equations

dave

Ok, i had a class in cfd many years ago, and i'm trying to refresh some code i wrote back in the day. It was for euler equations, using the MacCormack method for supersonic flow over a supersonic airfoil. See a contour plot of the rho*u field here:

http://home.mn.rr.com/curlydave/cfdsample.jpg

I am using forward differencing in the predictor, and backward differencing in the corrector. I have tried rotating the differencing direction every other time step but it seems to have convergence problems. The data shown is with 2nd order artificial viscosity of 0.01 or so, which i think is already pretty large. Does the trend in the figure suggest any particular problem with my code?

Be gentle, i'm an experimentalist.