The Saint-Venant equations solved by MASCARET constitute a hydrostatic model, meaning that they neglect the vertical component of fluid acceleration and assume that pressure follows a hydrostatic distribution throughout the water column. While this assumption is appropriate for long-wave phenomena such as floods or hydraulic jumps, it becomes inadequate when the characteristic wavelength of the perturbation becomes comparable to the water depth. This is notably the case for waves approaching coastlines or propagating in rivers and channels, such as Favre waves.

To reproduce the undulating structure of the free surface, MASCARET has been enhanced with a weakly nonlinear and weakly dispersive wave model. At present, this model is only available for the simulation of waves in channels with idealized geometries. Indeed, only rivers or channels with constant (i.e., prismatic) cross-sections can currently be represented. Although it still relies on simplifying assumptions, this model represents a first step toward the simulation of non-hydrostatic phenomena in MASCARET, opening the door to numerous future developments and research opportunities.

Examples of applications

Some numerical verification and validation cases are available in the MASCARET examples folder, including solitary and Favre waves.

Below is an example of Favre wave propagation following its generation (the flow rate is set to zero at t=3 162 s at the downstream boundary condition). It demonstrates the need to consider non-hydrostatic phenomena in order not to underestimate wave amplitude.

Modelling a hydropower plant triggering using the Saint-Venant equations: