open TELEMAC-MASCARET The mathematically superior suite of solvers

Hi,
I'm using version 7.0.1 and running a 3D-model for a bay, where there is a constant wind blowing straight into the bay. I'm expecting the current pattern to be flowing with the wind at the surface and going out of the bay at the bottom. However, when applying the key words:

VERTICAL TURBULENCE MODEL = 3
COEFFICIENT FOR VERTICAL DIFFUSION OF VELOCITIES = 1.E-6 /default value

HORIZONTAL TURBULENCE MODEL = 4
COEFFICIENT FOR HORIZONTAL DIFFUSION OF VELOCITIES = 1.E-6 /default value

the current is more looking as if the model was a 2D-model. With numerous of eddies in the bay (attaching an image). The current direction is also directed in the same direction for all the layers.

If I remove the key-words I get a current pattern that is as expected.

What am I doing wrong? I have used these key-words in previous versions of the Telemac3D with success.

Best regards,
Björn

Hello,

Note that with your choice of turbulence models, model 4 on the horizontal is automatically changed into 3, with a message in the listing. So actually you use k-epsilon on horizontal and vertical. The situation you describe, with all velocities in the same direction, can only be transitory, otherwise it would go again mass conservation. What you should see is the free surface slope due to the wind, about exactly like in 2D, and 3D currents which may be complicated, including the upwelling that you expect, but also 2D eddies due to differences of depth that trigger differences of depth-averaged friction.

With best regards,

Jean-Michel Hervouet