User Forum of Software BASEMENT

JAnton

User

Registered: 2015-06-04

Posts: 1

Problems with SmartJaeggi_multi

Hello,

i am trying to simulate a multigrain sediment transport with smartjaeggi_multi. The problem is that BASEMENT terminates the simulation after a few seconds because theta_critic becomes negative. I have tried a few adjustments to bypass this problem but nothing worked.

  - i have set the slope to a very low number

  - i have set a minimal theta_critic

Besides i am missing the first timestep. My simulations always start with 1min and 40sec.

greetings
JAnton

Lukas Vonwiller

Developer

Registered: 2014-09-04

Posts: 130

Re: Problems with SmartJaeggi_multi

Hi Janton

The smartjaeggi_multi formula is mainly recommended for 1-D simulations.
The reaseon is that the bed slope is very dominant in the transport rate according to the Smart & Jaeggi formula.
In 1-D you can choose between bed slope or energy slope, in 2-D not yet.
Therefore, in 2-D you can have locally very different and quite steep bed slopes, which gives you strange/high transport
rates according to the Smart & Jaeggi formula.

For morphological 2-D simulations with mulitple grain classes, I would rather recommend you mpmh, mpm_multi, parker or wu.

The minimal theta_critic is only applied for the Parker, Wu, and Van Rijn formula.

Hope this helps!

cheers,
Lukas