2D Noh shock test
This 2D L&W test consists of a circular infinite strength shock propagating out from the origin on a square Cartesian grid. There is an analytical solution, and with Gamma = 5/3 it is as follows:
The shock front expands at velocity V_s = 1/3
Inside the shocked region: (r < t/3)
 Density = 16
 Pressure = 16/3
 Velocity = 0
Outside the shock: (r > t/3)
 Density = 1.0 + t/r
 Pressure = 0.0
 Radial velocity = 1.0
Initial conditions
 Adiabatic index: Gamma = 5/3
 The density is uniform, d = 1.0 everywhere
 Pressure is set to P = 1.0e6 everywhere, as an approximation to zero pressure.
 The radial velocity, v(r), is 1.0 (ie flowing towards the origin). This gives an isothermal Mach number, M_i = (v * d)/ P = 1000.0.
Grid
 400 x 400 cells
 Domain: 0.0 < x < 1.0, 0.0 < y < 1.0 , 1st quadrant.
 Left and bottom boundaries are reflecting
 Top and Right boundaries are updated each cycle with the analytical solution for the density, plus fixed inflow velocity and pressure  to allow the inflow to continue for an extended period of time.
Algorithm settings
 CFL number: 0.8
 Striping correction on, artificial viscosity parameter: alpha = 0.05
 DivV threshold: 1.0, Scale: 1.0 (standard)
 Flattening: minimum 0.0, maximum 1.0 (standard)
Ending condition
 Time, t = 2.0
The code and configuration files plus output for Fyris to run the 2D Noh problem are available here.
Results

L1 Norms w.r.t. Analytical model at t = 2.0

L1 norm Density : 0.74 per cent

L1 norm Pressure : 0.87 per cent

QuickTime movies
t = 0.0  2.0, 20 frames
Final state