MODELING SURFACE ROLLERS AND UNDERTOW VELOCITY PROFILES

本論文では, 砕波帯周辺で顕著な戻り流れ流速の鉛直分布を予測するモデルを構築する. 戻り流れの起因力となる波やSurface Rollerの空間分布は汎用性の高いエネルギー平衡方程式で算定する. これらの諸量を全水深および波谷の上方でそれぞれ鉛直方向に積分したReynolds運動方程式に導入し, 得られた二層の運動方程式から水底および波谷で作用する剪断応力を定義する. これらの剪断応力を鉛直方向に線形内挿し, 砕波による乱れを考慮した渦動粘性モデルと組み合わせて, 戻り流れ流速の鉛直方向分布を解析的に導く. 最後にモデルを様々な実験条件に適用し, モデルの妥当性を検証する. 二層の運動方程式に基づくモデルは, 計算負荷が比較的小さく, 不規則波や任意地形条件への適用性が高い点で特徴的である.

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