Advecting Without Splitting Directions — The Bell-Colella-Glaz Unsplit Upwind Scheme
·6 min read
An unsplit second-order Godunov predictor that smears a rotating scalar far less
When FTCS Trembles, Upwind Goes Numb — First-Order Advection, Artificial Viscosity, and the CFL Trade
·4 min read
Why centered differencing explodes, why upwind survives, and what it pays for it