Cosqueric Nicolas 3rd year cfd
student

**MASTERING INDUSTRIAL CODES AND PARALELISM**

**1. Presentation
of the task**
**2. Presentation
of Telemac modelling system (version 4)**
**3. Computation
of a hydrodynamic problem with Telemac 2d**
**4. Installation
of Telemac version 5**
**5. Conclusion**

The purpose
of this task can be divided in two parts. On the one hand, the first objective
is to provide to hydraulics students the main basis in order to achieve
an hydrodynamic computation with Telemac2d. On the other hand, the installation
of the new version of telemac modelling system (version 5) was tested.
The product of this task is a manual which explain how to carries out a
computation with Telemac 2d, creates the computational grid with MATISSE
and analyses the result with RUBENS

**
introduction**

Telemac modelling
system is composed of several procedures (matisse, telemac2d, artemis...)
which allow to carry out computation in various fields such as hydrodynamic
computation, wave propagation, bed load transport ...

The numerical method for all the procedures is based
on a finite element procedure.

This code has been developing by LNHE (National Laboratory
of Hydraulics and Environment), a service of EDF-DER, which is currently
located in CHATOU, France (78).

This code is distributed by the company SOGREAH.

**
Telemac structure**

In order to
understand the process of a computation, the following scheme describes
telemac modeling system environment

Telemac2d solve
the equations of Barré de St Venant.The main results are water height
and mean velocity in vertical direction on a point of the computational
grid.

At first,
Telemac modelling system is difficult to use because some stages of the
computation are complex. Therefore, a simple computation was achieved on
a simple case : a rivers section. A short description of the computation
will be give in this part.

**
1. Load Telemac environment.**

Currently,
only the 4 version of Telemac is available at the ENSEEIHT. This version
runs only on Windows stations. ( see next part for the use on unix or sun
machines)

In order to run telemac, you have to load the file telenv.bat,
open a dos control window, and execute this file. It is not really friendly
therefore the installation of the 5 version on Linux or Sun machines could
be effective.

**
2. creation of the mesh.**

First, you
must have a bottom file, which is composed of three lines : the x and y
coordinates and the deep. This file can be create with SINUSX (digitalisation
of a map)

This file must have the extension .sx

Then you can
run matisse. Matisse allows to create the computational grid but you can
find another mesh editor. The use of matisse is quite complex at the beginning.
It is based on a triangularization of the bottom points after the definition
of a contour which is included in the bottom points domain. Moreover, matisse
allows to create the boundary condition, for example imposed height, imposed
flow...

After the process with matisse, 2 files have been created : the geometry file and the boundary condition file. This files must be provided in a specific file for the computation of telemac 2d.

**
3. The hydrodynamic simulation**

To carry out this computation, you have to provide 5 files :

- The geometry file

- The boundary conditions file

- The steering file

- The fortran file

- The results file

The first and
second file are create with matisse. The steering file is a text file where
you give all the information which are necessary for the computation, that
is to say the name of the five previous files, the numerical parameters
and the physical parameters. It is a list of Keywords.

The fortran
file allow to fix the size of the table for the computation. This file
allows to manage the memory.

The results
file is just the name of the file where the results will be stored.

**
4. Analyse the results with RUBENS**

RUBENS is the post processor of the telemac modelling system which allows to control the results of an hydrodynamic computation. The utilisation is quite complex at the beginnig such as MATISSE. With RUBENS, you can check the computational grid, visualise the bottom topography, the velocities or heights.

For example, in our simple case, we can obtain these kinds of pictures :

**Mesh and bottom topography :**

**Velocity vectors**

The principal
difference between the fourth and fifth version is the programming language
: Fortran 77 for Telemac 4 and Fortran 90 for Telemac 5. A contact was
made with Pierre Lang, from the SOGREAH, in order to obtain the fifth version.
Then, the computer specialist of the hydraulic department, Alexei Stoukov,
tried to install the fifth version on Linux Machines but there was lots
of problems uring the installation and at this time , 10/12/2001, this
version is not still available but it will be in a near future.

During this
task, I have learnt a new industrial code which is interesting for my personal
interrest because I would work in hydraulics fields, such as fluvial or
maritime problems. I have tried to write a friendly manual which allow
to someone who never use telemac to realise a simple computation. I think
that the installation of the fifth version on Linux will be great for the
former students of computational fluid mechanics and water science
and environment option because the current environment on windows machines
is quite arduous.