Svašek Hydraulics

Coastal, harbour and river engineering consultants


    Svašek Hydraulics

    Wave propagation in and
    around structures and
    harbour basins, diffraction,
    refraction, reflection,
    shoaling, directional spreading,
    frequency spreading, bottom
    friction and wave breaking.

HARES is a two-dimensional Finite Element numerical model (applying a Continuous Galerkin approach) for the determination of short wave propagation in near-shore domains, e.g. harbour basins. The model is based on the 2D Mild-Slope Equation and includes the physical phenomena of diffraction, refraction, reflection, shoaling, bottom friction, wave breaking and directional spreading. If needed frequency spreading can also be included. The influence of ambient current fields is not taken into account.

HARES has been developed by Svašek Hydraulics throughout the years from the early 1980s until today. It is especially useful in harbour and breakwater optimisation studies and for determining the natural frequencies of a harbour. HARES is mainly a linear model; only the bottom friction and wave breaking effects involve non-linearities. Following the finite element method, the two-dimensional model area is divided into a large number of triangles, the so-called elements. The size and shape of these elements may vary, so that wave propagation domains of arbitrary shape and bathymetry can be easily modelled. Using these 2D elements the Mild-Slope Equation can be solved locally, whereas boundary conditions of various types can be imposed on boundary elements along the domain borders.

The model input includes incoming wave characteristics (like wave height/period and near-shore wave direction), domain bathymetry, the water level and reflection coefficients for hydraulic structures and other physical borders. For each incoming harmonic wave HARES calculates the local wave climate, which is expressed by the complex wave amplitude. From this complex amplitude other wave quantities like the velocity potential can be easily derived, following linear wave theory.

During the period 2011-2012, the performance of HARES has been significantly improved in terms of calculation speed. Two new linear solvers and a new iteration algorithm have been implemented, such that the calculation time needed has been reduced by a factor 10 to 30.