open TELEMAC-MASCARET The mathematically superior suite of solvers

I'm running an analysis modeling the tides in a fjard by increasing the height of the water at the liquid boundary layer.

The attached files are the input files I use.

I ran this EXACT same analysis, but with VELOCITY DIFFUSIVITY =1 instead of VELOCITY DIFFUSIVITY =0.5 as in the current analysis, and it all worked fine. I'm doing some sensitivity studies to see how this affects the flow, that's why I'm changing the VD.

The analysis chugs along until time step 580, when it basically just 'collapses' (see attached picture).

Can anyone weigh in on this? I understand that the VD naturally is between 0-1 but can go to 500. How much will the VD affect the velocity of the flow about a km from the boundary layer?

Hello

I can not give a unique answer to you question.
Actually, your tun is simply diverging and I gues that if you decrease the time step slightly your run will finish normally.
On the other hand, a diffusivity coeffieicit more than 1 will diffuse a lot the velocity field. I believe that your study deals with tide, you can make the sensitivity on the tide calibration coefficients rather than on the VD.

with my kind regards
Riadh

Thanks, I'd check that out.

So, could I understand your suggestion as keeping the VD at 1 and playing with the tide calibration coefficients?

yes 1 or even less