Simulation Period and Time Step

The time step between two consecutive sediment transport calculations in MIKE 21 ST may be chosen to be either equal to or an integral multiple of the time step used in the hydrodynamic simulations. The program will determine the hydrodynamic conditions at the corresponding instant for every water point and will then calculate the sand transport rates.

The simulation period is specified on the basis of the HD-results, and may extend over the whole period used in the hydrodynamic simulation, or cover just a part of it.

Care should be exercised when selecting the simulation period and the time step for the sand transport calculations. Relevant hydrodynamic events that may produce enhanced sediment transport rates (e.g. strong current, maxi­mum wave height during a storm, etc.) and occur during a relatively short period of time should not be left out of the calculations by selecting a too long time step.