Evolution of Velocity Field and Vortex Structure during Run-Down of Solitary Wave over Very Steep Beach
| Autor: | Yun Ta Wu, Ching Piao Tsai, Wei-Ying Wong, Chang Lin, Hwung-Hweng Hwung, Rajkumar V. Raikar, Ming Jer Kao |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2018 |
| Předmět: |
Flow visualization
lcsh:Hydraulic engineering 010504 meteorology & atmospheric sciences Geography Planning and Development solitary wave similarity profile Aquatic Science 01 natural sciences Biochemistry 010305 fluids & plasmas run-down process Flow separation symbols.namesake lcsh:Water supply for domestic and industrial purposes lcsh:TC1-978 0103 physical sciences Froude number Hydraulic jump 0105 earth and related environmental sciences Water Science and Technology lcsh:TD201-500 hydraulic jump vortex structure Mechanics Vortex Adverse pressure gradient shear layer Particle image velocimetry flow separation Free surface symbols size height high-speed particle image velocimetry (HSPIV) Geology |
| Zdroj: | Water, Vol 10, Iss 12, p 1713 (2018) Water Volume 10 Issue 12 |
| ISSN: | 2073-4441 |
| Popis: | 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. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|