open TELEMAC-MASCARET The mathematically superior suite of solvers

Good afternoon

I have a question on how telemac 2D calculates the total bed shear stress. In the telemac 2d user manual I didn't find anything, but in the GAIA manual I found that:

tao = 0.5 * rho * Cf * (u^2 + v^2)

where Cf is the friction coefficient that the user indicates (in the manning formula for example) and u and v are the water velocities in x and y coordinates respectively.

I was just wondering if this is the formula that telemac 2d uses? I know that in other 2D software they also consider the water depth in this calculation, so I was wondering if the formula above is indeed for the telemac 2d module?

Kind regards,
Eduardo A

Hi Eduardo,

Telemac-2D can compute US (friction velocity) from which you can derive TAU (total bed shear stress).

But Cf is not the coefficient that the user indicates!
Cf is a dimensionless coefficient which is computed from the coefficient given by the user (Strickler value for example) according to a formula.
Have a look to github.com/CNR-Engineering/PyTelTools_me.../latex/equations.pdf section "3.3 - Friction coefficient".

Regards,
Luc

Perfect! Thank you very much for the explanation! Totally clear with the slides.

Kind regards,
Eduardo A