Hi there. Why can't i solve the same profile for the 2d prandtl-meyer expansion wave in prof. Anderson's book ? The velocity range is nearly the same, but mine has strong oscillation in y direction. Or the horizontal velocity profile has strong wiggle. Could anybody who tried this problem with his own code give me the clue ? Thank you in advance.

you included the artificial viscosity ? try by increasing it. also check boundary conditions. often small errors induced at the boundaries run havoc at corners.