Changes between Version 37 and Version 38 of u/erica/GudonovMethodEuler


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Timestamp:
05/06/13 14:32:19 (12 years ago)
Author:
Erica Kaminski
Comment:

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  • u/erica/GudonovMethodEuler

    v37 v38  
    7474=== Constraining the time step ===
    7575
    76 The time-step, is constrained by the CFL condition, which uses the max wave speed on the grid. The constraint used in the God. code here allows any given wave on the grid to travel a full delta_x in a time-step. In allowing this, we achieve a more efficient time-marching scheme, but with the assumption that wave interactions do not lead to wave accelerations. The CFL condition is given by:
     76The time-step, is constrained by the CFL condition, which uses the max wave speed on the grid. The constraint used in the God. code here allows any given wave on the grid to travel a full delta_x in a time-step. In allowing this, we achieve a more efficient time-marching scheme, but with the assumption that wave interactions do not lead to wave accelerations. The CFL condition, rearranged for dt, is given by:
    7777
    78 {{{#!Latex
     78dt = CFL*dx/smax
    7979
    80 CFL = smax/(dx/dt)
     80Where CFL is a coefficient that ranges from 0<CFL<1. A CFL close to 1, produces the largest time step, but it should be used cautiously during times when errors can be produced, for which a smaller time step should be used. In the God. code described here, the CFL was reduced by 80% for the first 5 time steps of the code.
    8181
    82 }}}
     82=== Boundary Conditions ===
     83
     84Transmissive boundaries were set up for the current code. These boundary conditions (BC's) theoretically do not produce waves at the boundary, and so allow waves to travel right through them.
    8385
    8486== The code ==