This paper gives an overall discussion about water level change on slopes under wave action, including wave runup, wave rundown and wave up-down amplitude, and a suggested formula for their calculation.
To improve the current understanding of the reduction of tsunami-like solitary wave runup by the pile breakwater on a sloping beach, we developed a 3D numerical wave tank based on the CFD tool OpenFOAM in this study. ...To improve the current understanding of the reduction of tsunami-like solitary wave runup by the pile breakwater on a sloping beach, we developed a 3D numerical wave tank based on the CFD tool OpenFOAM in this study. The Navier Stokes equations were applied to solve the two-phase incompressible flow, combined with an LES model to solve the turbulence and a VOF method to capture the free surface. The adopted model was firstly validated with existing empirical formulas for solitary wave runup on the slope without the pile structure. It is then validated using our new laboratory observations of the free surface elevation, the velocity and the pressure around a row of vertical slotted piles subjected to solitary waves, as well as the wave runup on the slope behind the piles. Subsequently, a set of numerical simulations were implemented to analyze the wave reflection, the wave transmission, and the shoreline runup with various offshore wave heights, offshore water depths, adjacent pile spaces and beach slopes. Finally, an improved empirical equation accounting for the maximum wave runup on the slope was proposed by taking the presence of the pile breakwater into consideration.展开更多
Nonlinear wave runup could result in serious wave impact on the local structures of offshore platforms in rough seas.The reliable and efficient wave runup prediction is beneficial to provide essential information for ...Nonlinear wave runup could result in serious wave impact on the local structures of offshore platforms in rough seas.The reliable and efficient wave runup prediction is beneficial to provide essential information for the design and operation of offshore platforms.This work aims to develop a novel data-driven method to achieve the nonlinear mapping underlying the wave-structure interactions.The Temporal Convolution Network(TCN)model was employed to predict the wave runup along the column of a semi-submersible in head seas.The incident wave and vertical motions including heave,roll,and pitch were fed into the TCN model to predict the wave runup.Experimental datasets were provided for training and test.Tak-ing both temporal and spatial dependency into consideration,the input tensor space was optimized from the perspective of physical meaning and practicality.Sensitivity analyses were conducted to obtain the optimum length of time window and evaluate the relative importance of input variables to wave runup prediction.Moreover,the effects of characteristics and size of the training dataset on the model perfor-mance were investigated to provide guidelines for training dataset construction.Finally,upon validation,the generated TCN model showed a strong ability to provide stable and accurate wave runup results un-der various wave conditions,and it is a potential alternative tool to achieve efficient but low-cost wave runup prediction.展开更多
Experiments of the runup of two solitary waves on a plane beach are carded out in a wave flume. The two solitary waves with the same amplitude and the crest separating distances are generated by using an improved wave...Experiments of the runup of two solitary waves on a plane beach are carded out in a wave flume. The two solitary waves with the same amplitude and the crest separating distances are generated by using an improved wave generation method. It is found that, with regard to the two solitary waves with same wave amplitude, the runup amplification of the second wave is less than that of the first wave if the relative crest separating distance is reduced to a certain threshold value. The rundown of the first solitary wave depresses the maximtlm runup of the second wave, If the leading solitary wave is of relatively smaller amplitude for the two solitary waves, the runup amplification is affected by the overtaking process of two solitary waves. It turns out that the runup amplification of the second wave is larger than that of the first wave if the similarity factor is approximately larger than 15, which means the larger wave overtakes the smaller one before the waves runup on a beach.展开更多
Based on the Navier-Stokes （N-S） equations for viscous, incompressible fluid and the VOF method, 2-D and 3-D Numerical Wave Tanks （NWT） for nonlinear shallow water waves are built. The dynamic mesh technique is ap...Based on the Navier-Stokes （N-S） equations for viscous, incompressible fluid and the VOF method, 2-D and 3-D Numerical Wave Tanks （NWT） for nonlinear shallow water waves are built. The dynamic mesh technique is applied, which can save computational resources dramatically for the simulation of solitary wave propagating at a constant depth. Higher order approximation for cnoidal wave is employed to generate high quality waves. Shoaling and breaking of solitary waves over different slopes are simulated and analyzed systematically. Wave runup on structures is also investigated. The results agree very well with experimental data or analytical solutions.展开更多
通过对收集黄庚的比赛技术参数,从绝对速度、助跑最后10 m 的分段速度(即节奏)和快速起跳的能力3 方面与鲍威尔等世界级运动员进行对比分析,发现黄庚除绝对速度明显差于对方外,助跑最后10 m 的分段速度由于受绝对速度的影响也均低于鲍...通过对收集黄庚的比赛技术参数,从绝对速度、助跑最后10 m 的分段速度(即节奏)和快速起跳的能力3 方面与鲍威尔等世界级运动员进行对比分析,发现黄庚除绝对速度明显差于对方外,助跑最后10 m 的分段速度由于受绝对速度的影响也均低于鲍威尔等,且节奏正好与他们相反,呈减速趋势,即后5 m 的分段速度低于前5 m 的分段速度。另外,由于助跑速度利用率偏高。展开更多
In this study, we examine the hydrodynamic characteristics of three rows of vertical slotted wall breakwaters in which the front and middle walls are permeable and partially immersed in a water channel of constant dep...In this study, we examine the hydrodynamic characteristics of three rows of vertical slotted wall breakwaters in which the front and middle walls are permeable and partially immersed in a water channel of constant depth, whereas the third wall is impermeable. The wave–structure interaction and flow behavior of this type of breakwater arrangement are complicated and must be analyzed before breakwaters can be appropriately designed. To study the hydrodynamic breakwater performance, we developed a mathematical model based on the eigenfunction expansion method and a least squares technique for predicting wave interaction with three rows of vertical slotted wall breakwaters. We theoretically examined the wave transmission, reflection, energy loss, wave runup, and wave force under normal regular waves. Comparisons with experimental measurements show that the mathematical model results adequately reproduce most of the important features. The results of this investigation provide a better understanding of the hydrodynamic performance of triple-row vertical slotted wall breakwaters.展开更多
The finite difference method and the volume of fluid （VOF） method were used to develop a three-dimensional numerical model to study wave interaction with a perforated caisson. The partial cell method was adopted to ...The finite difference method and the volume of fluid （VOF） method were used to develop a three-dimensional numerical model to study wave interaction with a perforated caisson. The partial cell method was adopted to solve this type of problem for the first time. The validity of the present model, with and without the presence of caisson structures, was examined by comparing the model results with experimental data. Then, the numerical model was used to investigate the effects of various wave and structure parameters on the wave force and wave runup of the perforated quasi-ellipse caisson. Compared with the solid quasi-ellipse caisson, the wave force on the perforated quasi-ellipse caisson is significantly reduced with increasing porosity of the perforated quasi-ellipse caisson. Furthermore, the perforated quasi-ellipse caisson can also reduce the wave runup, and it tends to decrease with the increase of the porosity of the perforated quasi-ellipse caisson and the relative wave height.展开更多
文摘This paper gives an overall discussion about water level change on slopes under wave action, including wave runup, wave rundown and wave up-down amplitude, and a suggested formula for their calculation.
基金financially supported by the National Natural Science Foundation of China(Grant Nos.51679014 and 51839002)the Hunan Science and Technology Plan Program(Grant No.2017RS3035)the Open Foundation of Key Laboratory of Key Technology on Hydropower Development of Hunan Province(Grant No.PKLHD201706)
文摘To improve the current understanding of the reduction of tsunami-like solitary wave runup by the pile breakwater on a sloping beach, we developed a 3D numerical wave tank based on the CFD tool OpenFOAM in this study. The Navier Stokes equations were applied to solve the two-phase incompressible flow, combined with an LES model to solve the turbulence and a VOF method to capture the free surface. The adopted model was firstly validated with existing empirical formulas for solitary wave runup on the slope without the pile structure. It is then validated using our new laboratory observations of the free surface elevation, the velocity and the pressure around a row of vertical slotted piles subjected to solitary waves, as well as the wave runup on the slope behind the piles. Subsequently, a set of numerical simulations were implemented to analyze the wave reflection, the wave transmission, and the shoreline runup with various offshore wave heights, offshore water depths, adjacent pile spaces and beach slopes. Finally, an improved empirical equation accounting for the maximum wave runup on the slope was proposed by taking the presence of the pile breakwater into consideration.
基金support of the National Natural Science Foundation of China(Grant Nos.52031006,51879158)Shanghai Sailing Program,China(Grant No.20YF1419800).
文摘Nonlinear wave runup could result in serious wave impact on the local structures of offshore platforms in rough seas.The reliable and efficient wave runup prediction is beneficial to provide essential information for the design and operation of offshore platforms.This work aims to develop a novel data-driven method to achieve the nonlinear mapping underlying the wave-structure interactions.The Temporal Convolution Network(TCN)model was employed to predict the wave runup along the column of a semi-submersible in head seas.The incident wave and vertical motions including heave,roll,and pitch were fed into the TCN model to predict the wave runup.Experimental datasets were provided for training and test.Tak-ing both temporal and spatial dependency into consideration,the input tensor space was optimized from the perspective of physical meaning and practicality.Sensitivity analyses were conducted to obtain the optimum length of time window and evaluate the relative importance of input variables to wave runup prediction.Moreover,the effects of characteristics and size of the training dataset on the model perfor-mance were investigated to provide guidelines for training dataset construction.Finally,upon validation,the generated TCN model showed a strong ability to provide stable and accurate wave runup results un-der various wave conditions,and it is a potential alternative tool to achieve efficient but low-cost wave runup prediction.
基金supported by the National Natural Science Foundation of China(Grant No.10972138)the Natural Science Foundation of Shanghai Municipality(Grant No.11ZR1418200)
文摘Experiments of the runup of two solitary waves on a plane beach are carded out in a wave flume. The two solitary waves with the same amplitude and the crest separating distances are generated by using an improved wave generation method. It is found that, with regard to the two solitary waves with same wave amplitude, the runup amplification of the second wave is less than that of the first wave if the relative crest separating distance is reduced to a certain threshold value. The rundown of the first solitary wave depresses the maximtlm runup of the second wave, If the leading solitary wave is of relatively smaller amplitude for the two solitary waves, the runup amplification is affected by the overtaking process of two solitary waves. It turns out that the runup amplification of the second wave is larger than that of the first wave if the similarity factor is approximately larger than 15, which means the larger wave overtakes the smaller one before the waves runup on a beach.
文摘Based on the Navier-Stokes （N-S） equations for viscous, incompressible fluid and the VOF method, 2-D and 3-D Numerical Wave Tanks （NWT） for nonlinear shallow water waves are built. The dynamic mesh technique is applied, which can save computational resources dramatically for the simulation of solitary wave propagating at a constant depth. Higher order approximation for cnoidal wave is employed to generate high quality waves. Shoaling and breaking of solitary waves over different slopes are simulated and analyzed systematically. Wave runup on structures is also investigated. The results agree very well with experimental data or analytical solutions.
文摘通过对收集黄庚的比赛技术参数,从绝对速度、助跑最后10 m 的分段速度(即节奏)和快速起跳的能力3 方面与鲍威尔等世界级运动员进行对比分析,发现黄庚除绝对速度明显差于对方外,助跑最后10 m 的分段速度由于受绝对速度的影响也均低于鲍威尔等,且节奏正好与他们相反,呈减速趋势,即后5 m 的分段速度低于前5 m 的分段速度。另外,由于助跑速度利用率偏高。
基金King Abdul-Aziz City for Science and Technology,General Directorate of Research Grants Programs(LGP-35-287)
文摘In this study, we examine the hydrodynamic characteristics of three rows of vertical slotted wall breakwaters in which the front and middle walls are permeable and partially immersed in a water channel of constant depth, whereas the third wall is impermeable. The wave–structure interaction and flow behavior of this type of breakwater arrangement are complicated and must be analyzed before breakwaters can be appropriately designed. To study the hydrodynamic breakwater performance, we developed a mathematical model based on the eigenfunction expansion method and a least squares technique for predicting wave interaction with three rows of vertical slotted wall breakwaters. We theoretically examined the wave transmission, reflection, energy loss, wave runup, and wave force under normal regular waves. Comparisons with experimental measurements show that the mathematical model results adequately reproduce most of the important features. The results of this investigation provide a better understanding of the hydrodynamic performance of triple-row vertical slotted wall breakwaters.
基金supported by the National Natural Science Foundation of China (Grant No. 50921001)the Science and Technology Program for Communications Construction in West China,of the Ministry of Transport of the People’s Republic of China (Grant No. 2004-328-832-51)
文摘The finite difference method and the volume of fluid （VOF） method were used to develop a three-dimensional numerical model to study wave interaction with a perforated caisson. The partial cell method was adopted to solve this type of problem for the first time. The validity of the present model, with and without the presence of caisson structures, was examined by comparing the model results with experimental data. Then, the numerical model was used to investigate the effects of various wave and structure parameters on the wave force and wave runup of the perforated quasi-ellipse caisson. Compared with the solid quasi-ellipse caisson, the wave force on the perforated quasi-ellipse caisson is significantly reduced with increasing porosity of the perforated quasi-ellipse caisson. Furthermore, the perforated quasi-ellipse caisson can also reduce the wave runup, and it tends to decrease with the increase of the porosity of the perforated quasi-ellipse caisson and the relative wave height.
