M1 RK1 and FLD: model comparisons
Supported stationary cases compare both closures at the same refinement level and physical time. Other cases retain M1 results only. Partial pairs remain visible while their partner is pending. References are attached to the model they describe.
M1 and FLD solve different transport closures. Both updates are first order in time. A small model discrepancy does not establish accuracy against an exact solution. M1 evolves radiation flux; FLD reconstructs diagnostic flux from its energy gradient. Flux differences are not errors in a shared radiation-momentum conservation law. FLD here supports stationary ideal gas with physical light speed on the CPU.
| Problem | Available reference | Comparison status |
|---|---|---|
| Gaussian Pulse | linearized analytic reference (M1); periodic constant-diffusion analytic reference (FLD limit) | L0: matched; L1: matched |
| Marshak | Su–Olson diffusion reference (M1); Su–Olson linear diffusion analytic reference (FLD limit) | L0: matched; L1: matched |