Modelling of coastal dynamics on unstructured mixed meshes under strong nonlinearity and pronounced baroclinicity (FVOM)

 

Numerical modelling of coastal zone dynamics provides basis for solving a wide range of hydrogeological, engineering and ecological problems. A novel three-dimensional unstructured-mesh model is applied to simulate the dynamics of the density field and turbulence characteristics. The model is based on a finite-volume discretization and works on mixed unstructured meshes composed of triangles and quads. Although triangular meshes are most flexible geometrically, quads are more efficient numerically and do not support spurious inertial modes of triangular cell-vertex discretization. Mixed meshes composed of triangles and quads combine benefits of both. In particular, triangular transitional zones can be used to join quadrilateral meshes of differing resolution.

Block diagram of the FVOM model (Graphic: Alexey Androsov)
The grid types, which are supported by FVOM (Graphic: Alexey Androsov and Vera Fofonova)
  • The Finite-Volume Ocean Model (FVOM) model solves three-dimensional primitive equations for the momentum, continuity, density-constituents, and turbulence-characteristics equations.   
  • FVOM uses a σ-coordinate in the vertical; it is coupled with GOTM turbulence closure sub-model, employs the Smagorinsky formulation for the horizontal viscosity and is equipped with a wetting and drying algorithm.
  • FVOM uses a mode-splitting technique to solve the momentum equations with two distinct time steps: external and internal mode time steps to accommodate the faster and slower barotropic and baroclinic responses, respectively.
FVOM. Vertically averaged velocity vectors. (Graphic: Alexey Androsov and Vera Fofonova)

'Box sill' experiment

(Video by Vera Fofonova)

'Wetting/Drying' experiment

(Video by Alexey Androsov)

Selected publications