Changes between Version 78 and Version 79 of FluxLimitedDiffusion

Timestamp:

03/27/13 21:38:24 (12 years ago)

Author:

Jonathan

Comment:

—

FluxLimitedDiffusion

@@ -92 +92 @@
 == Operator splitting ==
 Krumholz et al. perform Implicit Radiative, Explicit Hydro, Explicit Radiative
+
+Problem with AMR is we need coarse boundary values for E at t=0, and t=dt, and t = 2dt and we would like coarse boundary values at t=2dt to match solution from coarse grid...
+
+But the coarse update involves one implicit and one explicit solve.  Is there a way to interpolate the fine grid ghost zones in time without storing two time derivatives?  If we store dE_i+dE_e then we could do an explicit radiative update internally (E^n^ -> E*), then an implicit radiative update (E* -> E^n+1^ using the fully updated ghost zones (E^n+1^,,g,, = E^n^,,g,,+dE,,g,,) and then store the new time derivative (dE=E^n+1^-E^n^)
+
+This seems like it would work for the radiative field, but what about the internal energy terms?  We have an equation for e^n+1^ that is a function of E^n+1^, e* and E* but we have no way of getting E* in the ghost zones... and the 
+
+
+We could store dE_i and dE_e two implicit and two explicit solves...  so we need a way to 
+
+
+So the solution is perhaps to store the contributions from the implicit update and the non-conservative heating terms that appear in the internal energy equation.  Then we can update E in the ghost zones for the implicit and the first explicit term using the time derivative - and then use the new E to update e... Then the conservative explicit RadEnergy term can be calculated after the hydro step as well as the momentum explicit term - and then this flux can be coarsened - to keep the value of E in the coarse cells consistent with the value of E in the fine cells...  Since both will have been updated by the same eDot and fluxes...
+
+huh....
+
 In AstroBEAR this would look like:
 * Initialization
@@ -97 +112 @@
 * Step 1
  * Overlap d, p, e, E and do physical BC's
+ * Do ER which updates e,,0,, and E,,0,, using d,,1,,, e,,1,,, v,,1,, E,,1,,
  * Do IR which updates e,,0,,, and E,,0,, using d,,1,,, e,,1,,, E,,1,,
  * Update E,,2*mbc,, using Edot,,2*mbc,,