Contents

TELEMAC

Two-dimensional (2d) numerical simulation methods described on these pages use the freely available software open TELEMAC-MASCARET (in the following referred to as TELEMAC), which was started as a commercial code by the R&D group of Électricité de France (EDF). Since 2010, the TELEMAC-MASCARET Consortium took over the development (EDF R&D is still deeply involved) and freely provides the software and its source code under a GPLv3 license. Visit their website to learn more about TELEMAC.

Get Started

It is strongly recommended to install Debian Linux or one of its derivatives for working with TELEMAC (see the Virtual Machines (VMs) section in the Software chapter). Then, proceed with the installation of TELEMAC. Account for approximately 2 hours to get ready with TELEMAC.

General Introduction and Tutorial Guide

Analysis of a hydro-environment with TELEMAC involves pre-processing for abstracting the fluvial land scape, setting up control files, running a TELEMAC solver, and post-processing. The first-time user faces an overwhelming number of software options for pre- and post-processing. Besides, TELEMAC comes with a wide range of modules for 2d and 3d calculations of hydro-morphodynamic processes of various water bodies, from mountain rivers to coastal deltas under the influence of tides. Also, various sediment transport processes can be considered coupled with steady or unsteady flow conditions.

The tutorials on this website show how to:

  • Create a pure hydrodynamic model with steady-state runoff boundary conditions;

  • Implement unsteady boundary conditions (replace steady flow boundaries);

  • Activate modeling of sediment transport processes (morphodynamics) with TELEMAC’s Gaia module.

Here, the focus is on modeling small to medium-sized rivers.

Note

This page builds on descriptions provided in the telemac2d user manual.

Pre-processing

Pre-processing involves abstracting the river land scape into a computational grid (mesh) with boundary conditions. Many software tools can be used for this purpose and this website features two options for mesh generation and defining geometry boundary conditions:

  1. Use QGIS and the BASEmesh plugin. The QGIS Prepro option is convenient for creating geo-referenced 2d meshes and uses the pre-processing routines of BASEMENT. So this is not an officially recommended version by the TELEMAC developers, but rather a home-brewed option on this website.

  2. Use the National Research Council Canada’s Blue KenueTM GUI software. The Blue KenueTM Prepro option is preferably for Windows users and is somewhat cumbersome for creating geo-referenced point and line datasets to delineate the mesh.

  3. Use SALOME-HYDRO for generating computational meshes in MED geometry files (more details in the Telemac3d tutorial).

Model setup and run

The centerpiece of any TELEMAC model is the control (steering or CAS) file, which can be comfortably set up with Fudaa PrePro. The basic setup of a steady and a unsteady model are explained on the Model Setup page. In addition, explanations are provided on the use of the Gaia module for modeling morphodynamic (sediment transport) processes.

Post-processing

Artelia Eau et Environnement created the PostTelemac plugin for QGIS, which is a powerful and convenient tool visualizing and post-processing TELEMAC simulation results. The Telemac2d and Telemac3d tutorials provide guidance on the usage of the PostTelemac plugin and SALOME for post-processing SLF and MED results files, respectively.

The TELEMAC file structure

For any TELEMAC 2d simulation, the following input files are mandatory:

There are many more file formats, which are not computationally mandatory for running a simulation with TELEMAC, but essential in practice to yield reasonable results with a hydro-morphodynamic model (i.e., coupled hydrodynamic-sediment transport solver). Such optional files are:

  • Liquid boundaries file (e.g., for water surface elevation or flow rates)

    • Requires a stage-discharge relationship file

    • File format: .qsl

  • Friction data file

  • File format: tbl (ASCII)

  • Reference file to enable model validation (restart)

    • File format: .slf or .med

    • Check the TELEMAC docs

  • Restart file for setting initial conditions (.slf or .med)

  • Sections file to set control sections (e.g., verify flow rates, velocity, or water surface elevation)

  • Sources (e.g., water or sediment) data file

  • Zones file

  • Describes friction or other zonal properties

When hydraulic structures are integrated into a model, some of the following files are required (depending on the structure type):

  • Culverts data file

  • Weirs data file

In addition, a FORTRAN (.f) file can be created to specify special boundary conditions or the usage of either single or double precision

Tip

In hydro-morphodynamic modeling, single precision (i.e., 32-bit floats) rather than double precision (i.e., using 64-bit floats) is sufficient and much faster.

More input files can be defined to simulate oil spills, pollutant transport, wind, and tide effects.

Continue with setting up a mesh (2dm file) and a geometry file (SLF) with either

Detailed file descriptions

The steering file (CAS)

The steering file is the main simulation file with information about mandatory files (e.g., the selafin geometry or the cli boundary), optional files, and simulation parameters. The steering file can be created or edited either with a basic text editor or advanced software such as Fudaa-PrePro or BlueKenue. In this example, we will use BlueKenue.

The geometry file (SLF or MED)

The geometry file in slf (selafin or SERAFIN) format contains binary data about the mesh with its nodes. The name format of the geometry file can be modified in the steering file with:

/steering.cas GEOMETRY FILE   : 't2d_channel.slf'
GEOMETRY FILE FORMAT  : SLF  / or MED with SALOME preferably for 3d

MED files are typically processed with either SALOME or SALOME-HYDRO, which are featured in the Telemac3d tutorial.

The boundary conditions (CLI or BND/BCD) and liquid boundary (QSL) files

The boundary file in cli format contains information about inflow and outflow nodes (coordinates and IDs). The cli file can be opened and modified with any text editor, which is not recommended to avoid inconsistencies. Preferably use Fudaa-PrePro or BlueKenue for generating and /or modifying cli files.

In addition, users can define a liquid boundary conditions file (qsl) to define time-dependent boundary conditions (e.g., discharge, water depth, flow velocity or tracers).

The name format of the boundary conditions file can be modified in the steering file with:

/steering.cas
BOUNDARY CONDITIONS FILE : 'bc_channel.cli'
LIQUID BOUNDARIES FILE   : 'bc_unsteady.qsl'

Example (header only) for a boundary conditions file (cli):

2 2 2  0.000  0.000  0.000  0.000 2  0.000  0.000  0.000    101     1
2 2 2  0.000  0.000  0.000  0.000 2  0.000  0.000  0.000    102     2
2 2 2  0.000  0.000  0.000  0.000 2  0.000  0.000  0.000    103     3
...

Example for a liquid boundary conditions file:

# bc_unsteady.qsl
# Time-dependent inflow (discharge Q(2)) and outflow (depth SL(1))
T           Q(1)     SL(2)
s           m3/s     m
0.            0.     5.0
500.        100.     5.0
5000.       150.     5.0

The stage-discharge (or WSE-Q) file (txt - ASCII)

Define a stage-discharge file to use a stage (water surface elevation WSE) - discharge relationship for boundary conditions. Such files typically apply to the downstream boundary of a model at control sections (e.g., a free overflow weir). To use a stage-discharge file, define the following keyword in the steering file:

/steering.cas    STAGE-DISCHARGE CURVES FILE : YEs

Example for a stage-discharge file:

# wse_Q.txt
#
Q(1)     Z(1)
m3/s     m
50.     0.0
 60.     0.9
100.     1.5

The friction data file (tbl - ASCII)

This optional file enables the definition of bottom friction regarding the roughness law to use and associated function coefficients. To activate and use friction data, define the following keywords in the steering file:

/steering.cas
FRICTION DATA            : YES
FRICTION DATA FILE       : 'friction.tbl'

The results file (SLF or MED)

The name format of the results file can be modified in the steering file with:

/steering.cas
RESULTS FILE             : 't2d_channel_output.slf'

Because this file is generated by TELEMAC when the simulation is running, it does not need to exist for starting the simulation. A good option for visualizing the results file is the PostTelemac Plugin in QGIS: MED results files are typically processed with either SALOME or SALOME-HYDRO, which are featured in the Telemac3d tutorial.

BASEMENT Telemac 2d (coming soon)