open TELEMAC-MASCARET The mathematically superior suite of solvers

Hi

I have a quick question about Mesh Transformation =3 (fixed levels at a given altitude)

When I used it before, I specified the depth in relation to the surface:
e.g.
TRANSF_PLANE%I(4)=3
ZPLANE%R(4)=-28.D0

In my current model, I need to fix the layer in relation to the seabed. How can this be done?

Thanks,
Mohammed

Hi Mohammed

Maybe you should explain a little more what you want...
If you want to follow the seabed at a given height, I think it's not possible...
Mesh transformation = 3 is for horizontal plane so I cannot understand how you could relate the absolute value to the seabed.

Hope this helps

Hi Christophe,

I'm including in my model a representation of a tidal turbine mounted at a specific depth above the seabed, say 9m above the seabed. Therefore, I want to fix the layer where the turbine is located at 9m above the seabed.

If this is not possible with using Mesh Transformation =3, then is there any other way to do it?

Cheers,

Mohammed

Hi
If you know the location of the turbine, you know the bottom level and the you're able to fix the level of the plane 9m above the bottom level.

I'm not sure it exist another option to fix the mesh in the way you want and in an easy way...
I just imagine with a fix plane and by defining the sigma values (transf = 2)

Regards

Thanks for the quick reply. I still have confusion about transf=3 option. I would appreciate it if you can confirm that my understanding is correct.

I understand that transf=3 means I can fix a plane in relation to the surface, but because the surface depth will change with time (flood - ebb), then the depth of that plane will change accordingly but it will remain the same distance to the surface, correct?

Similarly, transf=2 will fix the percentage how far that layer of the seabed (say 0.2 i.e. it is located at 20% of the total depth above the seabed) at each timestep, which means its depth will change with time, correct?

Thanks for the help.

No, if you use 3, you fix the altitude of zplane
And you could mix with option 2 under or above...

Look in the user manual page 28 in the mesh definition part

Regards

I understand that part, but my question about the fixed altitude, what is the reference point to the altitude? is it the seabed or the surface? It is not so clear in the manual.

The example in page 28 shows:

DO IPLAN = 1,5
TRANSF_PLANE%I(IPLAN)=2
ENDDO
ZSTAR%R(1)=0.D0
ZSTAR%R(2)=0.2D0
ZSTAR%R(3)=0.5D0
ZSTAR%R(4)=0.7D0
ZSTAR%R(5)=0.8D0
DO IPLAN = 7,NPLAN
TRANSF_PLANE%I(IPLAN)=1
ENDDO
TRANSF_PLANE%I(6)=3
ZPLANE%R(6)=0.D0

So for plane 6, how is the altitude = 0?

I've read the manual a few times, and every time this point confuses me more :)

It's an absolute value.

It does make more sense now. That's very helpful, thanks.