## Modules

## SISYPHE - Sediment transport and bed evolution

SISYPHE is the state of the art sediment transport and bed evolution module of the TELEMAC-MASCARET modelling system.

SISYPHE can be used to model complex morphodynamics processes in diverse environments, such as coastal, rivers, lakes and estuaries, for different flow rates, sediment size classes and sediment transport modes.

## NESTOR - modeling dredging operations in the river bed

NESTOR coupled with the morphodynamic module SISYPHE offers the possibility of using documented data from dredging operations to model the resulting changes in the bottom level. Thus the period of time, the volume of sediment removed during that period of time and the size and location of the dredging site can be defined. This data can subsequently be used to determine the resulting bottom level for that site.

Bucket ladder dredger on the Danube

A second possibility of initiating dredging was incorporated in NESTOR for forecasting purposes. The objective was for dredging to be carried out automatically whenever too much sediment is deposited in the navigable areas of bodies of water.

## MASCARET 1-Dimensionnal free surface flow modelling

MASCARET includes 1-Dimensionnal free surface flow modelling engines. Based on the Saint-Venant equations, different modules can model various phenomenon over large areas and for varied geometries: meshed or branched network, subcritical or supercritical flows, steady or unsteady flows. MASCARET can represent:

- Flood propagation and modelling of floodplains
- Submersion wave resulting from dam break
- Regulation of managed rivers
- Flow in torrents,
- Canals wetting
- Sediment Transport
- Water quality (temperature, passive tracers ...)
Read more: MASCARET 1-Dimensionnal free surface flow modelling

## TOMAWAC - Wave propagation in coastal areas

Wave propagation off Paluel nuclear power station

TOMAWAC is used to model wave propagation in coastal areas. By means of a finite-element type method, it solves a simplified equation for the spectro-angular density of wave action. This is done for steady-state conditions (i.e. with a fixed depth of water throughout the simulation).

## ARTEMIS - Numerical simulation of wave propagation towards the shore and agitation into harbours

ARTEMIS is a scientific software dedicated to the simulation of wave propagation towards the coast or into harbours, over a geographical domain of about few square km. The domain may be larger for simulation of long waves or resonance. The frequency dependence and directional spreading of the wave energy is taken into account by ARTEMIS. The computation retrieves the main wave characteristics over the computational domain : significant wave height, wave incidence, orbital velocities, breaking rate, ...

## TELEMAC-3D - 3D Hydrodynamics

TELEMAC-3D is a three-dimensional (3D) model that uses the same horizontally unstructured mesh as TELEMAC-2D. The wave formulation for the updating of the free surface is used for efficiency. The model mesh is developed as a series of model planes between the bed and the surface planes. Flexibility in the placement of these planes permits the use of a sigma grid (each plane at a given proportion of the spacing between bed and surface) or a number of other strategies for intermediate plane location. One useful example is to include some planes which are at a fixed distance below the water surface, or above the bed. In the presence of a near surface thermocline or halocline this is advantageous in so far as mixing water between the near surface planes, where the greatest density gradients are located, can be avoided.

When drying occurs the water depth falls to zero exactly and the planes collapse to a zero inter-layer spacing. Finite volume style numerical techniques are used to ensure that both water and tracer can be well conserved in the presence of drying and subsequent rewetting.

The model was written primarily to solve the shallow water equations in 3D format but an option is also available to solve the governing equations including dynamic pressure so allowing shorter waves than those in a shallow water context (where wavelengths are required to be at least twenty times the water depth). This non-hydrostatic model formulation may also be important when modelling flows over trenches or on steep slopes.

Representation of velocity vectors of a TELEMAC-3D model near Torr Head (Northern Ireland)

## TELEMAC-2D - Two-dimensional hydrodynamic

Overflow subsequent to an embankment failure

TELEMAC-2D is used to simulate free-surface flows in two dimensions of horizontal space. At each point of the mesh, the program calculates the depth of water and the two velocity components.