Telemac 2d (coming soon)¶

This page is under construction. Expected release of this tutorial: Fall 2021.

Thank you for your patience.

requirements.html content=”The case featured in this tutorial was established with: -BlueKenue v3.12 (on Windows)-QGIS v3.16 (tested on Windows and Debian 10 Linux),-**`Fudaa PrePro v1.4 <install-telemac.html#fudaa>`__**(tested onWindows* and **Debian 10 Linux*), and ***-*`TELEMAC v8p2r0 <install-telemac.html#modular-install>`__*(stand-alone installation onDebian 10 Linux*).” %}

This tutorial uses descriptions provided in the telemac2d user manual.

Input files¶

Overview¶

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

Steering file
- File format: cas
- Prepare either with Fudaa PrePro or BlueKenueTM.
Geometry file
- File format: .slf (selafin)
- Prepare either with
Boundary conditions
- File format: .cli
- Prepare either with

The basic setup of the files is explained below.

Build geometry and computational mesh¶

Pass

Geometry File Option 1: BlueKenue¶

File description and reference to CAS¶

The geometry file in slf (selafin) 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 verify usage

Load points to create a geometry file (BK)¶

To load any point shapefile start BK and :

File > Import > ArcView Shape File > Navigate to the directory where the point shapefile lives > Select the All Files (.*)* option (in lieu of Telemac Selafin File (.slf)*) > Select the file (e.g., xyz.shp)
ALTERNATIVELY: Open any other point data file with File > Open > Navigate to DIR > look for .xyz or .dat files

Fig. 66 Importing a point shapefile in BK.¶

Right-click on points (X) and open the Properties
In the Properties window got to the Data tab > select Z(float) and Apply; then go to the ColourScale tab > Reset button > Apply > OK. Now, points (X) should have turned into points (Z)
Drag points (X) from Data Items to Views | 2d View (1)
ALTERNATIVELY: Use a three-dimensional (3D) view of the points: Go to the Window menu > New 3D View > drag points (X) from Data Items to Views | 3D View (1)

Fig. 67 The imported points a point shapefile in BK.¶

Generate a Mesh¶

TM solves the (depth-averaged) Navier Stokes equations along a computational grid based on either a finite element or a finite volume scheme. BK provides mesh generators for creating regular or unstructured computational grids (meshes). This example features the T3 Channel Mesher to generate a triangular mesh. Switch to a 2d View of the above points and walk down the following workflow.

Define the computational domain with a New Closed Line
- Find the New Closed Line button approximately below the Help menu
- Draw a polygon around the region of interest by clicking on the most outside points of the point cloud
- When finished drawing, press the Esc key and enter ClosedLine_domain in the Name field > click OK and OK (in the popup window)

Draw New Open Line objects to delineate the main (river) channel, levees, and right-left extents. Find the New Open Line button next to the New Closed Line button.

Geometry File Option 2: QGIS & BASEMESH¶

Follow the instructions in the QGIS data pre-processing section for creating a .2dm file.

Then…

Model setup with Fudaa Prepro¶

Fudaa PrePro facilitates the definition of boundaries, initial conditions, and setting up a steering file. To start Fudaa, open Terminal (Linux) or Command Prompt (Windows) and :

cd to the installation directory of Fudaa
start the GUI:
- Linux: tap sh supervisor.sh
- Windows: tap supervisor.bat

Boundary Conditions¶

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).

Stage-discharge (or WSE-Q) Relationship¶

Define a stage-discharge file (ASCII format) 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

Define steady flow boundaries¶

Qconst

Define unsteady flow boundaries¶

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 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

Activate morphodynamics (sediment transport with Gaia)¶

Qs

Run Telemac2d¶

Load environment and files¶

Load the TELEMAC Python variables:

cd ~/telemac/v8p1/configs
source pysource.openmpi.sh
config.py

Start a 2d hydrodynamic simulation (steady)¶

To start a simulation, cd to the directory where the simulation files live (see previous page) and launch the steering file (cas) with telemac2d.py:

cd /go/to/dir
telemac2d.py run_2dhydrodynamic.cas

Post-processing with QGIS¶

Install the PostTelemac plugin¶

Open QGIS’ Plugin Manager, go to the All tab and type posttelemac in the search field. Click on the Install button to install the PostTelemac plugin.

After the successful installation, click the Close button. The PostTelemac symbol should now be visible in the QGIS menu bar.

Open the PostTelemac plugin¶

Find the PostTelemac icon in the menu bar to open the plugin. By default, the plugin window will most likely open up in the bottom-right corner of the QGIS window. For better handling, click the detach symbol and enlarge the detached plugin window.

Fig. 68 The detached window of the PostTelemac plugin with the Display tab opened to render simulation variables such as VELOCITY U/V, VITESSE (principal absolute U-V velocity) or DEPTH.¶

Fig. 69 The detached window of the PostTelemac plugin with the Tools tab opened (e.g., to create shapefiles or GeoTIFF rasters).¶

Hydro-Informatics