LOCAL CONCENTRATION OF WAVES DUE TO ABRUPT ALONGSHORE VARIATION OF NEARSHORE BATHYMETRY

作者：Ranasinghe Roshan Suminda^*; Fukase Yutaro; Sato Shinji; Tajima Yoshimitsu

来源：Coastal Engineering Journal, 2011, 53(3): 201-222.

DOI：10.1142/S0578563411002331

• Wave concentration
• wave-current interaction
• long-waves
• abrupt depth configurations
• Boussinesq-model

Small-scale physical and numerical experiments were conducted to investigate the local concentration of waves (monochromatic and group) due to abrupt change of nearshore bathymetry in alongshore direction. Wave run-up motions along the shoreline were measured using an image analysis technique to compare localized concentration of wave energy, when waves propagate over a bathymetry composing rhythmic patterns of mild/steep slope bottom configurations. Measured alongshore variation of maximum wave run-up heights showed significant peak near the boundary, which has sudden alongshore change of depth, both under monochromatic and group wave trains. This phenomenon is found to be due to the interaction of waves with nearshore currents, which is further enhanced by excitation of long-wave components by breaking of group waves. Furthermore, this paper discusses results of preliminary experiments carried out to test the effectiveness of several shore protection structure layouts in mitigating such wave concentrations. Numerical simulations were performed using a model based on Boussinesq-type equations; coupled with a transport equation to model energy dissipation due to wave breaking.

• 出版日期2011-9