open TELEMAC-MASCARET The mathematically superior suite of solvers

Hi!

Im buiding a 3D-model for an area in and around a harbour. When a fresh water flow (700 m3/s) exits the harbour (port gate) and meets the ocean a very defined salinity profile occurs. When the fresh water "slides" on top of the salt water the cross sectional flow area decreases resulting in a quite dractic increase in velocity in the top layers where the fresh water flow occurs. (Wind SW 10 m/s).

Is this stratification and increase in velocity realistic? The flow seems to follow the same pattern some 1000 m up along the coast aswell. Ideas or suggestions of solutions/keywords that could increase the mixing?

I have tried no wind and a smaller flow (70 m3/s) with the same result.

Thanks in advance :)

Joanna

Hello,

Why not? This velocity is less than 1 m/s. The test case called lock-exchange also triggers non negligible velocities with a very small difference of salinity. If you consider that in the open sea a slope of 1 cm per km creates a current of 1 m/s, it is not so surprising to have such effects.

Due to the large mesh size in our applications the k-epsilon probably underestimates the turbulent diffusion but well, the advection schemes add some numerical diffusion and users generally ask for less mixing when they have stratifications.

With best regards,

Jean-Michel Hervouet