Integration of a shallow water model with a local time step

摘要: A Local Time Stepping (LTS) scheme was applied to an explicit Godunov–type shallow–water model improve run–time efficiency. Using LTS, the solution in each cell is advanced with largest power of two multiple global time step required for stability, δt, that satisfies local criterion stability.A careful sequencing flux calculations and updates ensures conservation. Test problems including practical applications show LTS achieves reductions ranging from 50 70% without loss accuracy. In addition, a four level coordinates steps 2δt, 4δt, 8δt performs best idealized test considered this study. Additional levels achieve no further reduction run time, some cases cause instability deteriorate