FLASH3.3 Release API

ROBODoc 4.99 manual

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[Functions] source/physics/Hydro/Hydro_computeDt





  Hydro_computeDt(integer(IN) :: blockID, 
                  integer(IN) :: myPE, 
                  real(IN) ::  x(:), 
                  real(IN) :: dx(:), 
                  real(IN) :: uxgrid(:),
                  real(IN) :: y(:), 
                  real(IN) :: dy(:), 
                  real(IN) :: uygrid(:), 
                  real(IN) ::  z(:), 
                  real(IN) :: dz(:), 
                  real(IN) :: uzgrid(:), 
                  real,pointer ::  solnData(:,:,:,:),   
                  real,(INOUT) ::   dtCheck, 
                  integer(INOUT) :: dtMinLoc(:) )


  Computes the timestep limiter for the hydrodynamical solver.  For pure
  hydrodynamics, the Courant-Fredrichs-Lewy criterion is used.  The sound
  speed is computed and together with the velocities, is used to constrain
  the timestep such that no information can propagate more than one zone
  per timestep.


  blockID --      local block ID
  myPE --         local processor number
  x, y, z --      coordinates
  dx, dy, dz --   deltas in each {x, y z} directions
  uxgrid, uygrid, uzgrid-- velocity of grid expansion in {x, y z} directions
  solnData --     the physical, solution data from grid
  dtCheck --     variable to hold timestep constraint
  dtMinLoc(5) -- array to hold location of cell responsible for minimum dt:
                 dtMinLoc(1) = i index
                 dtMinLoc(2) = j index
                 dtMinLoc(3) = k index
                 dtMinLoc(4) = blockID
                 dtMinLoc(5) = myPE