Modelling of a non-buoyant vertical jet in waves and currents

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• 作者：Zhen-shan XU (徐振山)^a ; ^b ; ^{zsxu2006@hhu.edu.cn" class="auth_mail" title="E-mail the corresponding author}Author Vitae ; Yong-ping CHEN (陈永平)^a ; ^b ; ^{ypchen@hhu.edu.cn" class="auth_mail" title="E-mail the corresponding author} ; Jian-feng TAO (陶建峰)^a ; ^b ; Yi PAN (潘毅)^b ; Chang-kuan ZHANG (张长宽)^b ; Chi-Wei LI (李志伟)^c
• 关键词：large eddy simulation (LES) ; turbulent jet ; wave ; cross-flow ; wave and cross-flow coexisting
• 刊名：Journal of Hydrodynamics, Ser. B
• 出版年：2016
• 出版时间：October 2016
• 年：2016
• 卷：28
• 期：5
• 页码：778-793
• 全文大小：7931 K

文摘

A generic numerical model using the large eddy simulation (LES) technique is developed to simulate a non-buoyant vertical jet in wave and/or current environments. The experimental data obtained in five different cases, i.e., one case of the jet in a wave only environment, two cases of the jet in a cross-flow only environment and two cases of the jet in a wave and cross-flow coexisting environment, are used to validate the model. The grid sensitivity tests are conducted based on four different grid systems and the results illustrate that the non-uniform grid system C (205×99×126 nodes with the minimum size of 1/10 jet diameter) is sufficiently fine for the modelling. The comparative study shows that the wave-current non-linear interaction should be taken into account at the inflow boundary while modelling the jet in wave and cross-flow coexisting environments. All numerical results agree well with the experimental data, showing that: (1) the jet under the influence of the wave action has a faster centerline velocity decay and a higher turbulence level than that in the stagnant ambience, meanwhile the “twin peaks” phenomenon exists on the cross-sectional velocity profiles, (2) the jet under a cross-flow scenario is deflected along the cross-flow with the node in the downstream, (3) the jet in wave and cross-flow coexisting environments has a flow structure of “effluent clouds”, which enhances the mixing of the jet with surrounding waters.