10H50 : n° 1394 Short term dynamics of a free falling jet due to solitonic collision

Julien Touboul Julien Chambarel Christian Kharif
LSEET
The impact of two steep solitonic waves propagating in counter directions leads to the formation of a free fall residual jet. We investigate numerically and theoretically the characteristics of this jet, including the criteria of formation, and the short term dynamics. The numerical approach is based on a boundary integral elements method, allowing to compute the pressure of the inner flow. A theoretical description based on potential flow theory is introduced to describe the short term evolution of the jet.

11H10 : n° 1393 Modutional instability in the presence of forcing and dissipation

Christian Kharif Roberto Kraenkel Miguel Manna Roland Thomas
Institut de Recherche sur les Phénomenes Hors Equilibre
The modulational instability of gravity wavetrains on the surface of water in the presence of wind and dissipation is considered. The wind regime is that of validity of Miles' theory and the viscosity is small. A perturbed nonlinear SchrÄodinger equation describing the evolution of a narrow-banded wavepacket is derived. It is found in the presence of wind forcing and dissipation that trains of long gravity waves are less unstable to modulational perturbations than trains of short gravity waves.

11H30 : n° 1400 Comparative analysis of classical models (MARS3D, AZOV3D) and lattice Boltzmann models for shallow water hydrodynamics computations

Alexander Sukhinov Elena Alexeenko Boris Sidorenko Alexander Chistyakov Franck Dumas
Taganrog Institute of Technology
Different numerical approaches of hydrodynamics of shallow water basins are considered and compared. Two approaches are developped in TIT-Russia: one of them is classical and based on numerical solution of the Navier-Stokes equations by Pressure-Correction method, another (developed several years ago) is based on the solution of the Lattice Boltzmann kinetic equation. The comparative analysis of these two approaches with MARS3D is performed for a shallow water basin example: «Etang de Berre».

11H50 : n° 1401 Turbulent mixing and stable current structures for Etang de Berre

Elena Alexeenko Alexander Sukhinov Alexander Chistyakov Bernard Roux Dominique Fougère
Taganrog Institute of Technology
Parameterization of coefficient of vertical turbulent exchange plays important role in the hydrodynamics of shallow water basin. Relevant parameters are determined on the basis of ADCP in situ experiments. They are implemented in Azov3D package developed at TIT-Russia. They are used to determine the currents in shallow water basins: Etang de Berre, Etang de Bolmon and Azov Sea. Comparison are performed with currents computed using another well known package (MARS3D).