Define LEVEL 6

2 3 GfsSimulation GfsBox GfsGEdge {} {
  Time { end = 40. }
  Refine LEVEL
  
  # adaptive grid
  AdaptVorticity { istep = 1 } { minlevel = 4 maxlevel = LEVEL cmax = 2e-2 }
  
  # box size
  PhysicalParams { L = boxsize }

  # The viscosity
  SourceViscosity 1./1000.

  # The initial condition
  Init { start = 0 } { U = u.cgd V = v.cgd }
  
  # save flow perturbation energy
  OutputScalarSum { istep = 10 } { awk '{ print $3,$5 }' > eevo } { 
    v = (U-tanh(y - boxsize/2))*(U-tanh(y - boxsize/2))+V*V 
  }

  # visual outputs
  OutputTime { istep = 10 } stderr
  OutputSimulation { step = 0.1 } stdout
}
GfsBox {}
GfsBox {}
1 2 top
1 1 right
2 2 right