SWIFT

Surface • Waves • Integral • Fast • Transformation

SWIFT is a new kind of deterministic wave model, which is efficient, accurate, robust and flexible. SWIFT is currently under development by SchäfferWaves.

This work in progress aims at developing a fast deterministic wave model applicable for problems with horizontal scales of several kilometers while including all potential-flow wave phenomena. The scope of SWIFT is to span the entire range from basic waves research to practical applications in coastal and offshore engineering. Initial trials have been very successful.

  • Compared with the classical mild-slope equation SWIFT includes irregularity and nonlinearity
  • Compared with Boussinesq models SWIFT eliminates the depth limitation and may include higher-order nonlinearity
  • Compared to higher-order spectral methods SWIFT allows for order-of-magnitude depth variations and eventually also for arbitrarily shaped lateral boundaries
  • Compared to boundary element models SWIFT allows for orders-of-magnitude increase in problem size or computational speed

SWIFT is suitable for stand-alone application but may take input from e.g. regional wind-wave models and provide detailed output for e.g. near field studies by Navies-Stokes equation solvers or physical experiments in wave flumes or basins.

SWIFT is basically a potential flow model, but wave breaking effects may be incorporated like in Boussinesq models. Field kinematics may be extracted at any water depth. SWIFT generally assumes mild-slope bathymetry, but local features like steep navigation channels that violate this assumption may be embedded.

SWIFT relies on the time-stepping of the free-surface boundary conditions while using a convolution approach to provide the necessary closure through the field equation and the bottom boundary condition. Throughout the time integration SWIFT is fully explicit in time and space and needs no system inversion.

SWIFT uses flexible-order numerics to minimize CPU time for user specified tolerance of numerical dispersion and dissipation.

The computational effort in SWIFT scales linearly with the horizontal dimension of the problem.