open TELEMAC-MASCARET The mathematically superior suite of solvers

hi, everyone.
I have the velocity field and depth data in different time step, and I have to use these data to solve the equation ∂T/∂t + U▽(T)=▽[K▽(T)] in the same time. I wonder can telemac solve the tracer conservation equation without working with hydrodynamic program?
Thank you very much.

Hello

you can edit telemac2d.f and comment the hydrodynamics computation and keep only tracer handling (everywhere it is written if(ntrac.gt.0)
This looks easy but I think that it will be a tricky action, so be careful.


with my best regards
Riadh

Hi,

You can do that by putting the lines below just after the three "CALL CVDF3D":
C
CALL OS( 'X=Y ', X=UD,Y=UN, C=0.D0 )
CALL OS( 'X=Y ', X=UC,Y=UN, C=0.D0 )
CALL OS( 'X=Y ', X=VD,Y=VN, C=0.D0 )
CALL OS( 'X=Y ', X=VC,Y=VN, C=0.D0 )
CALL OS( 'X=C ', X=WD,Y=UN, C=0.D0 )
CALL OS( 'X=C ', X=WC,Y=UN, C=0.D0 )
C
And by comment the "CALL WAVE_EQUATION".

With this two actions, you will cancel computing the water depth and the velocity. Then, read your fields to solve the thermal equation.

Regards,
Olivier

Thanks for your reply. First, my model is 2D, so I think maybe I cannot call cvdf3D?
Second, which subroutine I can add these lines to? What's more, what's the meaning of 'by comment the "CALL WAVE_EQUATION'?

Hi,

Yes, I have answered for a 3D model.
All the modifications have to be done in the "telemac2d.f".
Nearly the sames than in 3D.

Regards,
Olivier

I have tried, but failed. Can you tell me how to modify the subroutine in 2D?

Hi

You have to modify telemac2d.f subroutine.
Each time there is a computation of the water depth or velocity, you could comment the computation call and replace by a read of your data.

Of course, your data (water depth and velocity field) should be available for each node of the computation mesh...

Regards

Christophe

Hi, I wonder the UTILD,UCONV,U,UN are same? Should I read all of them from files?
nfo1=T2D_FILES(T2DFO1)%LU !read depth
nfo2=T2D_FILES(T2DFO1)%LU !read velocity
CALL OS( 'X=Y ', X=U,Y=UCONV)
CALL OS( 'X=Y ', X=V,Y=VCONV)
CALL OS( 'X=Y ', X=U,Y=UTILD)
CALL OS( 'X=Y ', X=V,Y=VTILD)

DO kk=1,NPOIN
read(nfo1,*) hhhh(kk,1:11)
read(nfo2,*) uuuu(kk,1:11),vvvv(kk,12:22)
WRITE(LU,*) 'T=',AT !AT is the current time
u%r(kk)=uuuu(kk,12-(at/3600))
v%r(kk)=vvvv(kk,23-(at/3600))
h%r(kk)=hhhh(kk,12-(at/3600))
enddo

Is it right?

Hi

I advise you to carefully read the theoretical manual of Telemac which is the book of Jean-Michel Hervouet "Hydrodynamics of free surface flows" where you will find the explanation of the different terms.

I'm not sure at 100% of the explanation hereunder but for me:
UN is the velocity field at time n
UTILD and UCONV are linked to method of fractional steps
U is the computed velocity field.

Nevertheless, if you look at the call of subroutine for the tracer, you will find which variable is used...

Hope this helps

Hello,

Yes, UN and VN are the components of the old velocity. UCONV and VCONV are the components of the advection field (they may be different from UN and VN). UTILD and VTILD are the result of the advection of UN and VN if the method of characeristics is used (in this case the advection-diffusion step done in cvdftr.f does not include advection and starts from UTILD and VTILD instead of UN and VN).

Only the advection field UCONV and VCONV is compatible with the continuity equation.

With best regards,

Jean-Michel Hervouet