Simulations for Design and Reconstruction of Breaking Waves in a Wavetank

Abstract

To determine forces on fixed and flexible structures such as wind mills and oil platforms, experiments in wave tanks are useful to investigate the impacts in various types of environmental waves. In this paper we show that the use of an efficient simulation code can optimize the experiments by designing the influx such that waves will break at a predefined position of the structure. The consecutive actual measurements agree well with the numerical design of the experiments. Using the measured elevation close by the wave maker as input, the software recovers the experimental data in great detail, even for rather short (up to L/D=1) and very steep breaking waves with steepness parameter (ak) till 0.4. The experiments were carried out in the TUD-wavetank and the simulation is done by HaWaSSI-AB, a spatial-spectral implementation of a Hamiltonian Boussinesq model with an eddy-viscosity breaking mechanism that is initiated by a kinematic breaking condition.

Phase-Resolved Wave Simulation over Isolated Seamount

“…Three experimental cases have also been used to validate the model: focusing and irregular waves over a bar and bichromatic breaking waves over a flat bottom [28]. Many experiments of breaking waves in focusing waves, bichromatic waves, and irregular waves above a flat bottom were conducted by [29], showing that HAWASSI is sufficiently accurate to support the design task prior to the actual experiment.…”

Spectral AB Simulations for Coastal and Ocean Engineering Applications

“…Then accurate generation of the desired waves is needed to obtain the correct positioning of all nonlinearly interacting wave phases and amplitudes at the position of the ship. This is illustrated here for an experiment executed at the wave tank of the Technical University of Delft [9,10]. The tank is 142 m long, 4.22 m wide with water level of 2.13 m. Generated at one side by a single piston-type flap, the waves By way of example, an experimental result, identified as TUD1403Foc6, is investigated here to show the quality of the generation in the tank of an a priori given (simulated) wave field in the basin, followed by an a posteriori reconstruction of the actually generated waves using the elevation at a first measurement point as influx for a simulation.…”

Freak wave

“…It can reconstruct and follow the designed wave quite well with some limitations. Therefore, the follow-up experiments by Kurnia et al [2015] could be done successfully after considering the capability of the equipment. Chapter 4…”

“…This is explainable as in the bi-chromatic wave experiment many breaking waves occur that are not accounted for in the nonlinear AB equation. The model and laboratory experiments about breaking waves are discussed in detail by Kurnia [2016], Kurnia et al [2015].…”

“…The experiments were executed in collaboration with TU Delft. Recently, there were follow-up experiments including breaking waves in the same wave tank with much success by Kurnia et al [2015].…”