Numerical Study on Plume Interaction Above An AlternatingDiffuser in Stagnant Water  

作　　者：匡翠萍 李行伟 刘曙光 顾杰 

机构地区：[1]Department of Geotechnical Engineering, Tongji University [2]Department of Civil Engineering, The University of Hong Kong, Pokfulam [3]College of Marine Science Technology, Shanghai Fisheries University

出　　处：《China Ocean Engineering》2006年第2期289-302,共14页中国海洋工程（英文版）

基　　金：ThisworkwassupportedbyagrantfromtheHongKongResearchGrantsCouncil(HKU-7518/03E);agrantfromTongjiUniversity(No.0200144005)

摘　　要：The plume interaction above an alternating diffuser in stagnant water is studied with 3D Reynolds-averaged NavierStokes equations （RANS） combined with a buoyancy-extended κ-ε model. The steady three-dimensional turbulent flow and temperature fields are computed by use of the finite volume method on a non-uniform high resolution orthogonal grid. The numerical predictions demonstrate a generic flow pattern for different turbulent heated jet discharges： the buoyant jets on each side of the diffuser first merge to form an essentially two-dimensional plume which bends back toward the diffuser centerline due to a low pressure cavity. In general, an under-pressure exists in the cavity until the plumes merge; the pressure increases to slightly positive afterwards. Two-dimensionality of the scalar and flow field is attained much later than the point of zero pressure. The position of merging point is governed by mainly four parameters - the discharge densimetfic Froude number, the port diameter and space, and the horizontal distance between alternating jet nozzles. A formula from numerical simulations is obtained through regression analysis and it is used to predict the position of plume merging point. The predicted temperature fields are comparable to previous experiments.The plume interaction above an alternating diffuser in stagnant water is studied with 3D Reynolds-averaged NavierStokes equations （RANS） combined with a buoyancy-extended κ-ε model. The steady three-dimensional turbulent flow and temperature fields are computed by use of the finite volume method on a non-uniform high resolution orthogonal grid. The numerical predictions demonstrate a generic flow pattern for different turbulent heated jet discharges： the buoyant jets on each side of the diffuser first merge to form an essentially two-dimensional plume which bends back toward the diffuser centerline due to a low pressure cavity. In general, an under-pressure exists in the cavity until the plumes merge; the pressure increases to slightly positive afterwards. Two-dimensionality of the scalar and flow field is attained much later than the point of zero pressure. The position of merging point is governed by mainly four parameters - the discharge densimetfic Froude number, the port diameter and space, and the horizontal distance between alternating jet nozzles. A formula from numerical simulations is obtained through regression analysis and it is used to predict the position of plume merging point. The predicted temperature fields are comparable to previous experiments.

关 键 词：alternating diffuser merging point plume interaction low pressure cavity ednsimetric Froude number turbulence modelling computational fluid dynamics κ-ε model enviromental hydraulics 

分 类 号：X55[环境科学与工程—环境工程]