Modelling the North Sea hydrodynamics in a management perspective

in Bulletin de la Société Royale des Sciences de Liège (1996), 65

On the residual advection of passive constituents

in Journal of Marine Systems (1996), 8(3-4), 147-169

In this paper, the different approaches used to simulate the long-term advection of passive constituents on tidal shelves are discussed in the framework of large scale hydrodynamic modelling. The direct ... [more ▼]

In this paper, the different approaches used to simulate the long-term advection of passive constituents on tidal shelves are discussed in the framework of large scale hydrodynamic modelling. The direct approach in which the unsteady mesoscale (tides and storm surges) and macroscale (monthly or seasonal mean processes) currents are used is very demanding in computer resources (CPU and memory). On the other hand, the use of residual velocities gives a larger understanding of the long-term transport processes and simplifies numerical treatments. However, the definition of such appropriate velocities is still an open question. In the context of large scale models, Lagrangian residuals are not applicable. Eulerian residual transport velocities fail to represent long-term motions when tidal non-linearities are important. The first order Lagrangian residual velocity introduced by Feng et al. (1986a) and generalized here is shown to be a very good solution. The North-Western European Continental Shelf (NWECS) is used as an example to compare the numerical solutions obtained with the different approaches. [less ▲]

3D turbulence field on the north-western european continental-shelf

in Tellus : Series A (1994), 46(2), 98-112

The 3-dimensional, non-linear, baroclinic, GHER mathematical model for the study of mesoscale motions (time scale of several hours to several days: tides, storm surges, ...) is described. Particular ... [more ▼]

The 3-dimensional, non-linear, baroclinic, GHER mathematical model for the study of mesoscale motions (time scale of several hours to several days: tides, storm surges, ...) is described. Particular attention is paid to the turbulent closure based on an evolution equation for the turbulent kinetic energy and a parametric expression of the mixing length (k-model). Appropriate boundary conditions and numerical techniques (mode-splitting, implicity, sigma-coordinate system, advection scheme) are described. The model is applied to the simulation of the M2 tide on the North-Western European Continental Shelf not only without wind but also in typical winter and summer conditions. Large spatial variations of the turbulent kinetic energy appear as a result of the variations of depth and tidal activity around the shelf. These variations are clearly related to the different turbulence regimes observed in summer, with frontal structures separating well-mixed waters from stratified ones. The structure and evolution of the vertical profiles of turbulence variables are described and explained in barotropic and baroclinic conditions, under different wind forcings. The evolution of these profiles at the M2 tide frequency largely depends on the eccentricity of the tidal ellipse. [less ▲]

Thre-dimensional, baroclinic, turbulent closure model of the general ciculation on the North-Western European Continental Shelf

Master of advanced studies dissertation (1992)