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Hello,

the Listing printout shows constantly that 10 iterations are needed for solving the bed load equation.
This value is the default value in MAXIMUM NUMBER OF ITERATIONS FOR ADVECTION SCHEMES.
So should I increase the value to say 20 or 30?

I would be very glad for any hints!
Clemens

Hello,

In the case of the Exner equation, the only scheme available so far is like advection scheme 13 or 14, and keeps the sediment layer height positive. This scheme consists of computing fluxes of sediment between points, and then transfering these fluxes segment by segment. Sometimes there is not enough sediment on a point to do the transfer, so the remaining quantity to be transferred is kept for a further iteration, in case extra sediment is brought to the point through another segment. Actually after a few iterations only a few remaining segments have pending quantities to be transferred and they can be left over as being non physical because they would trigger negative layers of sediment. So the number of iteration is not a very sensitive parameter and you can keep the maximum at 10. If you increase this number, the algorithm will stop only when there is not a digit changed in a loop on all segments (i.e. nothing more can be transferred given the quantities of sediment available), which is a very demanding criterion.

With best regards,

Jean-Michel Hervouet

Hello,

yes, in the meantime I did a test and indeed there are no differences.

Thank you very much for the explanation!

Best regards,
Clemens