open TELEMAC-MASCARET The mathematically superior suite of solvers

Hi,
I currently make simulation of fine sediment transport (grain size: 0.06-0.1mm) with SISYPHE and TELEMAC2d coupled (maybe afterward with TOMAWAC too) , but I don’t find the most adapted formula transport. The validity domains which are described in SISYPHE (formula 1, 2, 3, 6) are not allowable for this grain size. Can I use Bijker formula for this sediment?
Another question, what is the unit of the settling velocity? I did some test, and I find a factor 10E4 between the measure and the imposed settling velocity.
Thanks for your answer
Manuel

Dear Manuel,
according to the Wentworth classification, your sediment range [0.06mm-0.1mm] is classified as "very fine sand".
In the chapter 3 of the Erosion and Sedimentation Manual (chapter written by Chih Ted Yang), they recommend the following formulae for the median particle diameter [mm]:
* Ackers & White (1973) [0.065-32] (coarse silt-coarse gravel)
* Engelund & Hansen (1967) [0.065-32] (coarse silt-coarse gravel)
etc.
The Engelund & Hansen formula is programmed in Sisyphe. For a new formula, you can easily modify the subroutine SUBROUTINE QSFORM to add your own formula.

Bijker's formula is recommended when you have wave and currents.

The settling velocity is expressed in m/s. If the default value is not given in the steering file, the subroutine VITCHU_SISYPHE computes the velocity based on the grain size.

I hope it helps

Pablo

Thanks for your quickly response, I had found the domain validity of the pre-program formula in “Intercomparaison des formules de transport solide” written by Villaret C. But the validity domain specified for the Engelund & Hansen’s formula is 0.2 mm < D 50 < 1 mm. I will maybe study the Erosion and Sedimentation Manual to find another formula.
Regards
Manuel

Hi Manuel,
FYI, this manual is being updated and improved.

all the best,

Pablo