**Physical background**
**Numerical background**
**Classical errors**

Telemac 2d solve the equations of Barré de Saint-Venant in the two horizontal space co-ordinates U(x,y). The main results are the mean vertical velocity and water height.

The following phenomenons are taking into account :

- Propagation of long waves with accounting of non-linear effects.- Bottom friction- Coriolis forces- Wind and atmospheric pressure- Turbulence- Influence of horizontal gradient of temperature or ... on the density- follow trace- Singularity treatment such as :

The model is the following :

2.1 Input / Output

There is at least 4 files to provide in order to carry out a computation with Telemac-2D. Indeed, if you want to continue a previous computation, you have to provide the previous result file.2.1 Input

2.1.1 The geometry file

It contains the co-ordinates of the the computational grid, create by MATISSE, or an another mesh generator.1.2 The parameters fileIt is a text file which contains all the key-words which are necesary for the computation such as initial condition, numerical parameters or physical parameters.

1.3 The Fortran file

It contains all the subroutine of telemac which have been modified by the user. Moreover, it contains the principal program of Telemac. The main function of this program is to fix the language (french or english), and to fix the memory space by dimension the table A (real) and IA (integer). To fix the memory, you must know the number of points in the grid.

1.4 The boudary conditions file

It contains the definition of the boundary (fixed flow, fixed height, wall...). This file is created by the mesh generator.

For each point of the grid, there are the following values (for a cartesian grid) :

LIHBOR, LIUBOR, LIVBOR, HBOR, UBOR, VBOR, AUBOR, LITBOR, TBOR, ATBOR, BTOR, I, J, K

LIHBORBoundary type (integer)LIUBORBoundary type (integer)LIVBORBoundary type (integer)LITBORBoundary type (integer)HBORImposed height when LIHBOR = 5UBORImposed velocity U when LIUBOR=6VBORImposed velocity V when LIVBOR=6AUBORFriction coefficient at the boundary when LIUBOR orLIVBOR = 2TBORImposed value of the when LITBOR = 5ATBORflux coefficientBTBORflux coefficientNglobal numberI co-ordinate numberJco-ordinate number

Exemple :

2. Output

2.1 The listing file

It contains all the information concerning the computation2.2 The results fileIt contains the results of the computation. It is the file which will be compute with RUBENS

2.2 Hydrodynamic computation

2.2.1. Initial conditions

The initial conditions define the model at the time of the beginning of the computation. In the case of former computation, the initial conditions are described by the old results file.

The initial condition are fixed in the parameters file by the use of Key-words for simple case or by programming for complex case.

Key words

Initial conditions nature are fixed by the key words CONDITIONS INITIALES, which can take 5 values

COTE NULLE : Initialize the height of the free flow surface at the value 0 meter.

COTE CONSTANTE : Initialize the height of the free flow surface at the value given by the Key word 'COTE INITIALE'

HAUTEUR NULLE : Initialize the water heights to 0 meters. Therefore, the domain is dry.

HAUTEUR CONSTANTE: Initialize the water heights to the value given by the key word HAUTEUR INITIALE.

Continue a computation from an old computation

The name of the result file must be the name of the previous computation.

In the initial conditions field, you have to imposed the following keywords :

SUITE DU CALCUL take the value OUIFICHIER DU CALCUL PRECEDENT is the name of the previous computation file.

2.2.2. Boundary conditions

The type of the boundary condition is fixed by the value of LIHBOR, LIUBOR, LIVBOR, LITBOR, which can take a value from 0 to 6.

Possible choice :

Height conditionLiquid boundary with fixed heightLIHBOR = 5Liquid boundary with free heightLIHBOR = 4Liquid boundary with incident waveLIHBOR = 1Solid frontierLIHBOR = 2Velocity or flow conditionsLiquid boundary with fixed flowLIUBOR/LIVBOR = 5Liquid boundary with fixed velocityLIUBOR/LIVBOR = 6Liquid boundary with free velocityLIUBOR/LIVBOR = 4Solid boundary with friction orLIUBOR/LIVBOR = 2Solid boundary with 1 or 2 of the velocity nullLIUBOR/LIVBOR = 0

Nevertheless, for a Telemac computation, you can fixed the conditions type in matisse which is well adapted for telemac2d

2.2.3. Prepare the computation

Now, you have to fix all the parameters in the parameter file and the name of the different file.In the fortran file, you fix the size of the table IDIMIA and IDIMA (You have to now the number of points in the grid)

Moreover, you have to fix the parameter in the parameter file such as :

the step time with the key-word PAS DE TEMPSNumber of step time with NOMBRE DE PAS DE TEMPS.

You can also choose a break criteria :

If you fixed the key word ARRET SI UN ETAT PERMANENT to the value OUI, Telemac2d will stop when the permanent state is reached.You can also break the computation if there is divergence with the key word CONTROLE DES LIMITES=OUI.Bottom friction

Telemac allows to the user to choose the formula for the bottom friction. It is defined in key-word COEFFICIENT DE FROTTEMENT which can take a value from 0 to 5.

ValueFormula0nothing1Haaland2Chézy3Strickler4Manning5Nikuradse

You can also choose a modele for the turbulence with the key word MODELE DE TURBULENCE.

ValueModele1Constant viscosity2Elder3k-Epsilon4Smagorinski

2.2.4. Run the computation

In the dos-control window, type telemac2d Name_of_the_parameter_file. (in batch mode, type telemac2d -b Name_of_the_parameter_file

3.1 Size of IDIMA and IDIMIA.

The computation stop if the size of these tables is too little. Therefore, be carreful and when you achieved mesh in Matisse, don't forget to note the number of grid point.