open TELEMAC-MASCARET The mathematically superior suite of solvers

Hi everybody !

I have a doubt the secondary current coefficient.

The Engelund formula for the taking account of the secondary current is the following:

tan(delta)=7(h/r)

I would like to change the coefficient :"7" into another coefficient ( for example 2,3 or 4 etc...)

For making this operation can I just put in the steering file the keyworld:"SECONDARY CURRENT ALPHA COEFFICIENT := 2,3..." or I have to use a subroutine?

Thank you for the attention

Caro Fabio,
I don't think that could be a good idea to change this value. This value has been proposed in the paper by Engelund (1974) and has "physical" meaning for values of roughness coefficients that are found in practice.
Instead, you can evaluate the sensitivity of your results to the variation of alpha, that is an adjustment parameter for the evaluation of the radius bend (for example, if you have or not bedforms).

For your particular problem, I'd tune-on the sediment transport formula to first match the observed sediment fluxes (if available).

Further discussions next week at the TUC in Karlsruhe!

ciao ciao

Pablo

ref.
Engelund (1974), JHD.
Yalin and Ferreira da Silva (2001)
Kitanidis & Kennedy (1984), JFM

Hello Pablo,

May I follow up on this question...?

I'm trying to simulate morphodynamics in a meandering channel of which I have data that shows the coef. A should be around 3. How should I change this value A? The user's manual v8p5 (the version I'm using) only says that alpha_sc =1 corresponds to A=7 (attached). May I know how alpha_sc is converted to A?

Thank you so much!
Jason