Evolution of velocity field and vortex structure during run-down of solitary wave over very steep beach
學年 107
學期 1
出版（發表）日期 2018-11-23
作品名稱 Evolution of velocity field and vortex structure during run-down of solitary wave over very steep beach
作品名稱（其他語言）
著者 Chang Lin; Wei-Ying Wong; Ming-Jer Kao; Ching-Piao Tsai; Hwung-Hweng Hwung; Yun-Ta Wu; Rajkumar V. Raikar
單位
出版者
著錄名稱、卷期、頁數 Water2018 10(12), p.1713
摘要 An experimental results on the spatio-temporal variation of velocity field and vortex structure, generated from the separated boundary layers on the offshore side of the still-water shoreline, during the run-down process of non-breaking solitary waves over a 1:3 sloping beach are presented. Three waves having the incident wave-height to water-depth ratios (H0/h0) of 0.363, 0.263, and 0.171 were generated in a wave flume. Two flow visualization techniques and high-speed particle image velocimetry were employed. The primary topics and new findings are: (1) Mechanism of the incipient flow separation, accompanied by formation of the separated shear layer from the beach surface, is elucidated under the adverse pressure gradient, using the fine data of velocity measurements very close to the sloping boundary. (2) Occurrence of hydraulic jump subsequently followed by development of the tongue-shaped free surface and projecting jet is demonstrated through spatio-temporal variation in the Froude number. It is confirmed by a change in the Froude number from supercritical to subcritical range as the free surface rapidly rises from the onshore to offshore side. (3) A complete evolution of the primary vortex structure (including the core position, vortex size, and velocity distribution passing through the vortex core) is first introduced systematically, together with the illustration of temporal variation in the topological structure. The non-dimensional shoreward distance of the vortex core section decreases with the increase in the non-dimensional time. However, the non-dimensional size height of the primary vortex increases with increasing non-dimensional time. (4) Two universal similarity profiles for both the wall jet flow and the shear layer flow demonstrate independency of the two similarity profiles of the wave-height to water-depth ratio and the beach slope. The similarity profiles indicate the promising collapse of the data from three previous studies for 1:20, 1:10, and 1:5 sloping beaches.
關鍵字 solitary wave;run-down process;high-speed particle image velocimetry (HSPIV);flow separation;shear layer;hydraulic jump;vortex structure;size height;similarity profile
語言 en
ISSN
期刊性質 國外
收錄於 SCI EI
產學合作
通訊作者
審稿制度 是
國別 CHE
公開徵稿
出版型式 ,電子版
相關連結

機構典藏連結 ( http://tkuir.lib.tku.edu.tw:8080/dspace/handle/987654321/115624 )