Measurements of wave modulation and breaking

Abstract

To investigate the evolution of wave modulation and wave breaking, a series of elaborate experiments were conducted in a super wave flume (300 m × 5.0 m × 5.2 m) at Tainan Hydraulics Laboratory. Two wave trains of initial regular waves and initial imposed sidebands were generated by a wave maker with active wave absorption using an electro-hydraulic server feedback control system. The wave profiles were recorded by 66 high-resolution capacitance-type wave gauges positioned along the wave flume, and connected to a specially designed data acquisition system to collect a large number of parallel inputs in the long flume. Experimental data were obtained on wave modulation and related wave breaking. The long time evolution of the nonlinear wave train and the corresponding wave spectra are demonstrated for both breaking and non-breaking cases. Specifically, the periodic modulation and demodulation of wave train is observed at post-breaking stage.

Two-layer Boussinesq models for coastal water waves

“…Bichromatic wave experiments were conducted in THL of the National ChengKung University of Taiwan by Huang and Chiang [34] in a 300 m-long wave flume. An accurate simulation of wave evolution in such a long distance is a demanding test to the models' phase velocity, group velocity, and nonlinear wave-wave interactions.…”

Measurements of Surface Kinematics and Temperature in the Surf and Swash Zones Using Infrared Image Velocimetry

“…The ultra-sonic wave gauges were moved with the carriage to the four positions of the IRIV measurements (p1 -p4). The wave profiles were recorded simultaneously with a 50 Hz sampling rate using the Microsoft NT based Multi-Nodes-Data-Acquisition-System (MANDAS), developed by THL (Hwung and Chiang, 2005). The streamwise and vertical flow velocities were measured by an EMCM with a sampling rate of 50 Hz, which was set close to the FOV boundary of the infrared image.…”

A σ‐coordinate non‐hydrostatic model with embedded Boussinesq‐type‐like equations for modeling deep‐water waves

“…Particularly, wave-wave interactions can cause a great deal of energy re-distribution and significantly influence the evolution of deep-water wave groups. In this paper, the experiments conducted by Hwung and Chiang's [40] are used to validate the model's capability in simulating the evolution of bi-chromatic deep-water wave in a wave tank of water depth h = 3. In the model, the 2D vertical numerical wave tank has a length of 300 m and an undisturbed water depth of 3.5 m, following the setup in [40].…”

“…In this paper, the experiments conducted by Hwung and Chiang's [40] are used to validate the model's capability in simulating the evolution of bi-chromatic deep-water wave in a wave tank of water depth h = 3. In the model, the 2D vertical numerical wave tank has a length of 300 m and an undisturbed water depth of 3.5 m, following the setup in [40]. A sponge layer is placed at the last 50 m to minimize unwanted wave reflection.…”