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浙江大学学报(工学版)
Journal of ZheJiang University (Engineering Science)  2019, Vol. 53 Issue (2): 336-346    DOI: 10.3785/j.issn.1008-973X.2019.02.017
Water Resources and Ocean Engineering     
Hydrodynamic performance of two vertical plates penetrating system mounted over stepped bottom
Chen WANG1(),Zheng-zhi DENG1,*(),Da-wei MAO2
1. Ocean College, Zhejiang University, Zhoushan 316021, China
2. Power China Zhongnan Engineering Co. Ltd, Changsha 410014, China
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Abstract  

The hydrodynamic performance of regular wave-two vertical plates-topography coupled system, comprised by two vertical penetrating plates mounted over a stepped bottom (submerged breakwater) with different dimensions, were analyzed by the use of the toolbox waves2Foam based on the open source software OpenFOAM. The effects of the gap between the two plates and the dimension of the stepped bottom on the hydrodynamic characteristics, such as reflection and transmission coefficients, viscous dissipation ratio of wave energy, and relative oscillating amplitude of the free surface between the two plates, were examined systematically under the action of different incident waves. In addition, the nonlinear effect of wave on the hydrodynamic parameters was investigated. Results showed that a proper dimension of the stepped bottom, for example that the ratio of topography length to wavelength was approximately equal to 1.0, was beneficial for reducing the reflection and transmission coefficients and obtaining a satisfactory viscous dissipation ratio. The presence of the stepped bottom enhances the oscillating amplitude of the free surface between the two plates and effectively improves the capacity of capturing wave energy. Furthermore, the increase of wave height leads to the reduction of the reflection and transmission coefficients, the enhancement of the viscous dissipation ratio, and the drop of the oscillating amplitude of the free surface between the two plates.

Key words： OpenFOAM      two vertical plates      stepped bottom      viscous dissipation      wave nonlinearity     
Received: 04 April 2018      Published: 21 February 2019
CLC:  O 352  
Corresponding Authors: Zheng-zhi DENG     E-mail: cqhfwchen@zju.edu.cn;zzdeng@zju.edu.cn
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Chen WANG
Zheng-zhi DENG
Da-wei MAO
Cite this article:

Chen WANG,Zheng-zhi DENG,Da-wei MAO. Hydrodynamic performance of two vertical plates penetrating system mounted over stepped bottom. Journal of ZheJiang University (Engineering Science), 2019, 53(2): 336-346.

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http://www.zjujournals.com/eng/10.3785/j.issn.1008-973X.2019.02.017     OR     http://www.zjujournals.com/eng/Y2019/V53/I2/336


台阶式地形上双垂板透空系统的水动力学特性

基于开源计算流体动力学软件OpenFOAM中的工具箱waves2Foam，通过在双垂板透空系统下方布置不同尺寸的台阶式地形（潜堤），对规则波-双垂板-地形耦合系统的水动力学特性进行数值分析. 在不同入射波况作用下，研究双垂板的间距和台阶式地形的尺寸对结构系统前/后的反/透射系数、波能的黏性耗散率及双垂板间的液面相对振动幅值等水动力参数的影响. 此外，探究波浪非线性对相关水动力参数的影响. 结果表明：合理布置台阶式地形尺寸，如令地形的长度与波长的比值约为1.0，能够有效减小双垂板系统的波能反射和透射，并可获得适中的黏性耗散率；地形的存在会加剧双垂板间的液面振动幅度，有效提升两板间的波能捕获能力；波高的增大会造成反射和透射系数的减小，增大黏性耗散率，降低板间液面振动幅值.


关键词： OpenFOAM,  双垂板,  台阶式地形,  黏性耗散,  波浪非线性 
Fig.1 Schematic diagram of absorbing waves for numerical wave tank
Fig.2 Numerical convergence study for grid size and time step
T/s x=L x=2L x=3L x=4L x=5L
0.9 0.019 9 0.019 9 0.019 8 0.019 7 0.019 6
1.0 0.019 9 0.019 8 0.019 8 0.019 7 0.019 7
1.1 0.020 0 0.019 8 0.019 8 0.019 9 0.019 9
1.2 0.019 9 0.019 9 0.019 8 0.019 9 0.019 7
Tab.1 Wave heights for places with different distances from wave-making boundary under different periods
Fig.3 Results of absorbing wave at inlet and outlet
Fig.4 Schematic diagram of two vertical plates model and wave surface monitoring locations
Fig.5 Comparison between present numerical wave elevation results and analytical, experimental results for two vertical plates model
Fig.6 T-type structure model for verification of separation of reflection coefficient
Fig.7 Comparison of results for separation of reflection coefficient
Fig.8 Schematic diagram of two vertical plates with varied sea-bottom
工况 固定参数 变化参数Ⅰ 变化参数Ⅱ
1 H=0.02 m, T=1.2 s b/h=0.1，0.2，0.3，0.4，0.5 B/L=0，0.4，0.5，0.6，0.9，1.0，1.1，1.5，2.0
2 b/h=0.1, T=0.9 s H=0.005，0.010，0.015，0.020，0.025 m B/L=0，0.4，0.5，0.6，0.9，1.0，1.1，1.5，2.0
Tab.2 Parameters for model calculation of two vertical plates system over a stepped bottom
Fig.9 Time series of wave surface elevations for gages in interior of two vertical plates
位置属性 测点G ΔL/m 位置属性 测点G ΔL/m
1 3.10 6 11.86
双垂板前定水深 2 7.00 双垂板内部 7 11.95
3 8.00 8 12.04
双垂板前变水深 4 11.60 双垂板后方 9 15.00
5 11.80 — — —
Tab.3 Locations for monitoring wave surface elevation in numerical wave tank
Fig.11 Transmission coefficient against relative crest width under different interval ratios of two vertical plates
Fig.12 Energy dissipation rate against relative crest width under different interval ratios of two vertical plates
Fig.13 Streamline diagram at different intervals without stepped bottom
Fig.14 Streamline diagram at different intervals with stepped bottom
Fig.10 Reflection coefficient against relative crest width under different interval ratios of two vertical plates
Fig.15 Relative wave height between plates against relative crest width
Fig.19 Nonlinear effect on energy dissipation rate of two vertical plates system under different incident wave heights
Fig.16 Nonlinear effect on high order waves for outside and inside of vertical plates
Fig.17 Nonlinear effect on reflection coefficient of two vertical plates system under different incident wave heights
Fig.18 Nonlinear effect on transmission coefficient of two vertical plates system under different incident wave heights
Fig.20 Nonlinear effect on relative wave height between plates of two vertical plates system under different incident wave heights
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