MIKE FLOOD is unsurpassed by its reliability and accuracy in urban and rural flood hazard modelling. The MIKE by DHI development team have been carrying out innovative optimisations of the MIKE FLOOD coupling and we are very pleased to notify our users of the following two improvements that directly improve stability and simulation speed.
Stability improvements
The numerical stability of MIKE FLOOD couplings between MIKE 21 and MIKE URBAN has been enhanced. The enhancement will typically result in a larger simulation time step to be used for the coupled models.
Simulation speed improvements
With the aim of reducing the simulation runtime we have been optimising the MIKE FLOOD code in the coupling algorithm between the 2D overland flow engine and the 1D river/urban engines. This has resulted in a significant reduction of the runtime.
The numerical scheme is unchanged and therefore the simulation results will not change as a results of this modification. The result for four real world MIKE 21 and MIKE URBAN coupled cases are presented in the table below and the simulation runtime is reduced by a factor between 2 and 13. Preliminary testing on MIKE 21 and MIKE 11 model shows a similar reduction in runtime.
Reduction in runtime will be most significant for models with a high number of flooded MIKE 21 cells and a high number of MIKE 21 cells receiving water from links to MIKE 11 and/or MIKE URBAN. To significantly reduce the simulation runtime the average number of flooded MIKE 21 cells multiplied by number of linked MIKE 21 cells should be more than approximately 108.
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