3D Euler equations - Backward facing step 
  Problem description 
This example has been inspired by the planar diffraction of a shock-wave over a sharp corner (see 
2D backward facing step).
  Initial / Boundary Conditions 
 
  Numerical Simulation  
-  Two-dimensional Euler-equations for an ideal gas (Air with gamma=1.4) 
-  Dimensional splitting, Roe solver, MUSCL variable reconstruction with Van Albada limiter 
-  Calculation with CFL-No. 0.95 to time t=1.5 
-  AMR-computation with a coarse grid of 60x40x40 cells 
    3 grid levels: 
-  Calculation of 70 time steps 
-  2 levels with refinement factor 2 are used. 
-  Finest level corresponds to 240x160x160 grid (6.144 M cells) 
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RalfDeiterding - 06 Dec 2004