波狀水躍流場之水理分析

The Study of Undular Jumps

胡富雁(Fu-Yan Hu)

指導教授 ： 周憲德 ； 吳祚任

國立中央大學/工學院/土木工程學系/碩士(2007年)

摘要

波狀水躍屬自由邊界問題，本研究以數值模擬及水工模型試驗探討波狀水躍流場特性。模式使用有限體積法離散計算網格，並配合流體體積法決定自由液面，Navier-Stokes equation採用投影法估計，且加入大渦流紊流模式處理紊流剪應力。實驗以洩水閘門產生超臨界流，藉由調整尾水檻控制下游水深，觀察波狀水躍並以模式驗證。

本研究發現，波狀水躍產生不均勻底床剪應力，波谷下剪應力較強。流場速度變化僅在水流上層，但無渦度產生，故其消能較慢。由流場之動壓分佈，波谷的動壓大於波峯的動壓，造成水面的抬升。

關鍵字

底床剪應力 ； 大渦流紊流模式 ； 流體體積法 ； 波狀水躍

並列摘要

In order to investigate the flow characteristic of the two-dimensional undular jump, this paper proposes a numerical simulation and conduct a hydraulic physical model to validate the propose scheme. In this paper, the finite volume method and volume of fluid coupled with large eddy simulation technique to simulate the free-surface profile of undular jump. Then, the proposed scheme is applied to the numerical simulation of the physical model. The comparisons between the simulated result and the measured data show that the proposed scheme can reasonably simulation the free surface profile and the velocity distribution of wave crest and wave trough. The results highlight the nonuniformity of the boundary shear stress distributions.

並列關鍵字

undular jump ； boundary shear stress. ； large eddy simulation ； volume of fluid

參考文獻

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