Changes between Version 35 and Version 36 of u/erica/MusclHancock


Ignore:
Timestamp:
06/18/13 12:49:14 (11 years ago)
Author:
Erica Kaminski
Comment:

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  • u/erica/MusclHancock

    v35 v36  
    8585 [[Image(evolve.png, 35%)]]
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    87 3.
    88  
     873. Solve the new Riemann problem
     88
     89  [[latex($ \frac{\partial \vec{u}}{\partial t} + \frac{\partial f(\vec{u})}{\partial x} = 0 $)]]
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     91
     92  [[latex($ u(x,0) =  \{ ^{\bar{u}_i^r,~~~~ x <0}_{\bar{u}_{i+1}^l, ~~x>0} $)]]
     93
     94  using the evolved extrapolated boundary values. The solution of this problem is then used in the Godunov flux, which is used in updating cell i. Recall the Godunov flux is simply,
     95
     96  [[latex($ f_{i+1/2} = f(u_{i+1/2}(x/t=0))$)]]
     97
     98  i.e. the numerical flux at the intercell boundary equals the physical flux evaluated at the similarity solution of the LRP (local Riemann Problem) at that boundary.
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     101At this point, we are left with a higher order accurate code, but not one that is free of spurious oscillations near large gradients. To circumvent this, we need to add a TVD measure. There are some different ways of doing this, i.e. limited slopes, flux-limiters, and slope limiters. Here we focus on slope limiters.
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    96 At this point, we are left with a higher order accurate code, but not one that is free of spurious oscillations near large gradients. To circumvent this, we need to add a TVD measure.
     103= Slope Limiters =
    97104
    98105= Algorithm Outline =