Revision as of 11:13, 20 November 2024 view source Pavlina Monhartova (talk \| contribs) Bureaucrats, Administrators 5,368 edits →Why is my HPC model getting unstable? Why am I getting a timestep error? Why are my control numbers so low? ← Older edit		Latest revision as of 11:14, 20 November 2024 view source Pavlina Monhartova (talk \| contribs) Bureaucrats, Administrators 5,368 edits →Why is my HPC model getting unstable? Why am I getting a timestep error? Why are my control numbers so low?
Line 100: The below suggestions can be implemented to eliminate the instability and/or the decrease in control numbers: * Specify initial water level for the whole model with <font color="blue"><tt>Set IWL</tt></font> command or locally with <font color="blue"><tt>Read GIS IWL</tt></font> command. The wet cells can limit the adaptive timestep through the <u>[[HPC_Adaptive_Timestepping#HPC_2D_Timestep \| Shallow Wave Celerity Number]]</u>, and prevent the HPC solver from using big timesteps. * Use <font color="blue"><tt>Timestep Maximum</tt></font> command to cap the maximum timestep to not get too high. A good Timestep Maximum value to start with might be a half the cell size in metres, e.g. if the cell size is 5m, the Timestep Maximum is to be 2.5 seconds. The .hpc.tlf file can be checked ofif further refinement is needed. <br>

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