Posted Fri, 22 May 2015 03:17:46 GMT by sophie liu
Hi everyone,

I am facing a problem using MIKE 21 to simulate river flood.
I use smoothed DEM to represent bathymetry and also dfs0 for initial water surface. I've checked that the initial condition assured the boundary points are wet.
I use flux as the inputs for two inflow boundaries(west) and tide level for one outflow boundary(east), it gives "elevation too low on flooded boundary", which stops at the last point on the eastern outflow boundary.
After I reduce one of the inflows, it gives another error "one point wide open flux boundary". Are these two typical problems when setting up boundary conditions? Are there general reasons why they happen?

Posted Wed, 01 Jul 2015 15:36:17 GMT by Mathieu Hellegouarch
Hi Sophie,

Did you manage to fix your problem?

These two errors are indeed typical errors related to handling of boundaries in MIKE 21. They both happen when a cell from the boundary becomes dry during the simulation.

They can often be avoided by :
- setting a constant topography along the boundaries, on a width of e.g. 3 rows or columns.
- making sure the cells are initially flooded on the same number of rows / columns.

Best regards,
Posted Mon, 10 Aug 2015 07:13:08 GMT by sophie liu
Hi Mathieu,

Thanks for reply. I no longer have that problem now.
But I will post another topic to discuss what issue I encountered now.


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