Changes between Version 30 and Version 31 of FluxLimitedDiffusion
- Timestamp:
- 03/20/13 12:43:32 (12 years ago)
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FluxLimitedDiffusion
v30 v31 228 228 229 229 === Reflecting Boundary === 230 Reflecting boundary should be fairly straightforward. This an be achieved by setting [[latex(\alpha_g = 0)]] which zeros out any flux - and has the same effect as setting [[latex(E^{ n+1}_g=E^{n+1}_i)]]230 Reflecting boundary should be fairly straightforward. This an be achieved by setting [[latex(\alpha_g = 0)]] which zeros out any flux - and has the same effect as setting [[latex(E^{*}_g=E^{*}_i)]] or [[latex(E^{n+1}_g=E^{n+1}_i \mbox{ and } E^{n}_g=E^{n}_i)]] 231 231 232 232 === Constant radiative flux === 233 233 To have a constant radiative flux we must have 234 [[latex(\alpha_g \left ( E^{ n+1}_i-E^{n+1}_g \right ) = F_0 \frac{\Delta t}{\Delta x})]]234 [[latex(\alpha_g \left ( E^{*}_i-E^{*}_g \right ) = F_0 \frac{\Delta t}{\Delta x})]] 235 235 236 236 Which we can solve for 237 [[latex(E^{ n+1}_g = E^{n+1}_i - \frac{F_0 \Delta t}{\alpha_g \Delta x})]]237 [[latex(E^{*}_g = E^{*}_i - \frac{F_0 \Delta t}{\alpha_g \Delta x})]] 238 238 239 239 but when we plug this into the coefficient matrix the terms with [[latex(\alpha_g)]] cancel and we just get [[latex(F_0 \frac{\Delta t}{\Delta x})]] in the source vector