流れ場における不規則波の波浪変形

Abstract

本研究は，位相平均モデルの一つである波作用量平衡式に基づき，流れの影響を考慮した砕波限界式とエネルギー減衰，および波峰方向のエネルギー移流(回折効果)を組み込んだ波浪変形予測モデル(WABED: Wave Action Balance Equation with Diffraction effect model)を作成した。まず，1次元伝播における理論値と計算値を比較して両者は良く一致することを確かめた。次に，離岸流モデル場における波浪変形解析を行って，回折効果を導入すると波高の集中が緩やかになることを示した。

This study develops a wave prediction model of multidirectional random waves in a wave-current coexisting field, based on a wave action conservation equation. In the wave model, the current effects on wave breaking and energy dissipationare taken into account as well as wave diffraction effect. The present wave prediction model is called WABED (Wave ActionBalance Equation with Diffraction effect model). First the predictions by the WABED are compared with theoretical values inthe cases of one-dimensional adverse and following current fields. Both results agree very well. Secondly, for a case of ripcurrent field, the significant wave heights are estimated by the present wave model, and these results are compared with thepredictions by the SWAN, developed by the Delft University of Technology. There appear differences between the presentmodel predictions and the SWAN predictions due to the different formulation of current related wave breaking and energydissipation in addition to wave diffraction effect.