期刊文献+
共找到13篇文章
< 1 >
每页显示 20 50 100
Using a Time-domain Higher-order Boundary Element Method to Simulate Wave and Current Diffraction from a 3-D Body 被引量:2
1
作者 刘珍 滕斌 +1 位作者 宁德志 孙亮 《Journal of Marine Science and Application》 2010年第2期156-162,共7页
To study wave-current actions on 3-D bodies a time-domain numerical model was established using a higher-order boundary element method(HOBEM).By assuming small flow velocities,the velocity potential could be expressed... To study wave-current actions on 3-D bodies a time-domain numerical model was established using a higher-order boundary element method(HOBEM).By assuming small flow velocities,the velocity potential could be expressed for linear and higher order components by perturbation expansion.A 4th-order Runge-Kutta method was applied for time marching.An artificial damping layer was adopted at the outer zone of the free surface mesh to dissipate scattering waves.Validation of the numerical method was carried out on run-up,wave exciting forces,and mean drift forces for wave-currents acting on a bottom-mounted vertical cylinder.The results were in close agreement with the results of a frequency-domain method and a published time-domain method.The model was then applied to compute wave-current forces and run-up on a Seastar mini tension-leg platform. 展开更多
关键词 wave-current diffraction time-domain simulation drift force higher-order boundary element method (HOBEM)
下载PDF
Multi-domain Boundary Element Method with Dissipation
2
作者 Xiaobo Chen (12) xiao-bo.chen@bureauveritas.com Wenyang Duan (3) 《Journal of Marine Science and Application》 2012年第1期18-23,共6页
The wave diffraction and radiation around a floating body is considered within the framework of the linear potential theory in a fairly perfect fluid. The fluid domain extended infinitely in the horizontal directions ... The wave diffraction and radiation around a floating body is considered within the framework of the linear potential theory in a fairly perfect fluid. The fluid domain extended infinitely in the horizontal directions but is limited by the sea bed, the body hull, and the part of the free surface excluding the body waterplane, and is subdivided into two subdomains according to the body geometry. The two subdomains are connected by a control surface in fluid. In each subdomain, the velocity potential is described by using the usual boundary integral representation involving Green functions. The boundary integral equations are then established by satisfying the boundary conditions and the continuous condition of the potential and the normal derivation across the control surface. This multi-domain boundary element method (MDBEM) is particularly interesting for bodies with a hull form including moonpools to which the usual BEM presents singularities and slow convergence of numerical results. The application of the MDBEM to study the resonant motion of a water column in moonpools shows that the MDBEM provides an efficient and reliable prediction method. 展开更多
关键词 multi-domain boundary element method (MDBEM) fairly perfect fluid moonpool resonance DISSIPATION
下载PDF
THE SIMULATION AND ANALYSIS OF TANK SLOSHING WITH POROSITY GIRDER BY MULTI-DOMAIN BOUNDARY ELEMENT METHOD 被引量:4
3
作者 HE Zhao ZHU Ren-chuan MIAO Guo-ping 《Journal of Hydrodynamics》 SCIE EI CSCD 2010年第4期546-553,共8页
The simulations of nonlinear sloshing in both two-dimensional and three-dimensional liquid tanks with porosity girder are carried out in time domain by using the Multi-domain Boundary Element Method(MBEM).The compar... The simulations of nonlinear sloshing in both two-dimensional and three-dimensional liquid tanks with porosity girder are carried out in time domain by using the Multi-domain Boundary Element Method(MBEM).The comparison of the present results and the references is conducted and shows they agree well with each other.The three-dimensional effect and the influence of the width of liquid tank and the height and porosity of the girder on the natural period of the model are also discussed. 展开更多
关键词 multi-domain boundary element method (MBEM) SLOSHING girder with porosity time domain NONLINEARITY natural period three-dimensional effect
原文传递
A Method for Calculation of Low-Frequency Slow Drift Motions Based on NURBS for Floating Bodies 被引量:2
4
作者 刘文玺 任慧龙 《China Ocean Engineering》 SCIE EI 2009年第3期399-414,共16页
Through a higher-order boundary element method based on NURBS (Non-uniform Rational B-splines), the calculation of second-order low-frequency forces and slow drift motions is conducted for floating bodies. In the fl... Through a higher-order boundary element method based on NURBS (Non-uniform Rational B-splines), the calculation of second-order low-frequency forces and slow drift motions is conducted for floating bodies. In the floating body's inner domain, an auxiliary equation is obtained by applying a Green function which satisfies the solid surface condition. Then, the auxiliary equation and the velocity potential equation are combined in the fluid domain to remove the solid angle coefficient and the singularity of the double layer potentials in the integral equation. Thus, a new velocity potential integral equation is obtained. The new equation is extended to the inner domain to reheve the irregular frequency effects; on the basis of the order analysis, the comparison is made about the contribution of all integral terms with the result in the second-order tow-frequency problem; the higher-order boundary element method based on NURBS is apphed to calculate the geometric position and velocity potentials; the slow drift motions are calculated by the spectrum analysis method. Removing the solid angle coefficient can apply NURBS technology to the hydrodynamic calculation of floating bodies with complex surfaces, and the extended boundary integral method can reduce the irregular frequency effects. Order analysis shows that free surface integral can be neglected, and the numerical results can also prove the correctness of order analysis. The results of second-order low-frequency forces and slow drift motions and the comparison with the results from references show that the application of the NURBS technology to the second-order low-frequency problem is of high efficiency and credible results. 展开更多
关键词 splines higher-order boundary element method second-order low-frequency force slow drift motions irregular frequencies spectrum analysis order analysis
下载PDF
An iterative Rankine boundary element method for wave diffraction of a ship with forward speed 被引量:2
5
作者 何广华 《Journal of Hydrodynamics》 SCIE EI CSCD 2014年第5期818-826,共9页
A 3-D time-domain seakeeping analysis tool has been newly developed by using a higher-order boundary element method with the Rankine source as the kernel function. An iterative time-marching scheme for updating both k... A 3-D time-domain seakeeping analysis tool has been newly developed by using a higher-order boundary element method with the Rankine source as the kernel function. An iterative time-marching scheme for updating both kinematic and dynamic free-surface boundary conditions is adopted for achieving numerical accuracy and stability. A rectangular computational domain moving with the mean speed of ship is introduced. A damping beach at the outer portion of the truncated free surface is installed for satisfying the radiation condition. After numerical convergence checked, the diffraction unsteady problem of a Wigley hull traveling with a constant forward speed in waves is studied. Extensive results including wave exciting forces, wave patterns and pressure distributions on the hull are presented to validate the efficiency and accuracy of the proposed 3-D time-domain iterative Rankine BEM approach. Computed results are compared to be in good agreement with the corresponding experimental data and other published numerical solutions. 展开更多
关键词 Rankine panel method higher-order boundary element method (HOBEM) iterative scheme Wigley hull wave exciting forces
原文传递
Numerical investigation of solitary wave action on tworectangular boxes with a narrow gap 被引量:2
6
作者 NING Dezhi SU Xiaojie ZHAO Ming 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2016年第12期89-99,共11页
Based on the time-domain higher-order boundary element method(HOBEM), a two-dimensional numerical wave flume is developed to investigate solitary wave interaction with two rectangular boxes with a narrow gap.In the nu... Based on the time-domain higher-order boundary element method(HOBEM), a two-dimensional numerical wave flume is developed to investigate solitary wave interaction with two rectangular boxes with a narrow gap.In the numerical model, the fully nonlinear boundary conditions are satisfied on the free surface, the mixed Eulerian-Lagrangian method is adopted to track the transient water surface and the fourth-order Runga-Kutta method is used to predict the velocity potential and wave elevation on the free surface. The acceleration potential technique is used to compute the transient wave forces along the wetted object surface. A piston-type wavemaker is used to generate solitary waves. The proposed model is validated by comparing the simulated wave run-up and the wave loads with the published experimental and numerical results of the reflection of a solitary wave from a vertical wall. Then, numerical experiments are performed to study the effects of the narrow gap and the size of each box on the wave run-ups at the two sides of the two-box system and in the narrow gap between two boxes, and the wave loads on the two boxes. The interaction between double solitary waves with a time interval between them with a two-box system is also investigated. 展开更多
关键词 narrow gap numerical wave flume solitary wave wave force higher-order boundary element method
下载PDF
Numerical analysis of added mass and damping of floating production,storage and offloading system 被引量:9
7
作者 Ke Wang Xi Zhang +1 位作者 Zhi-Qiang Zhang Wang Xu 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 2012年第3期870-876,共7页
An integral equation approach is utilized to in- vestigate the added mass and damping of floating produc- tion, storage and offloading system (FPSO system). Finite water depth Green function and higher-order boundar... An integral equation approach is utilized to in- vestigate the added mass and damping of floating produc- tion, storage and offloading system (FPSO system). Finite water depth Green function and higher-order boundary ele- ment method are used to solve integral equation. Numeri- cal results about added mass and damping are presented for odd and even mode motions of FPSO. The results show ro- bust convergence in high frequency range and can be used in wave load analysis for FPSO designing and operation. 展开更多
关键词 FPSO. Added mass Damping. Green function higher-order boundary element method
下载PDF
Nonlinear numerical simulation on extreme-wave kine-matics 被引量:1
8
作者 NING Dezhi TENG Bin LIU Shuxue 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2009年第3期75-81,共7页
A fully nonlinear numerical model based on a time-domain higher-order boundary element method (HOBEM) is founded to simulate the kinematics of extreme waves. In the model, the fully nonlinear free surface boundary c... A fully nonlinear numerical model based on a time-domain higher-order boundary element method (HOBEM) is founded to simulate the kinematics of extreme waves. In the model, the fully nonlinear free surface boundary conditions are satisfied and a semi-mixed Euler-Lagrange method is used to track free surface; a fourth-order Runga-Kutta technique is adopted to refresh the wave elevation and velocity potential on the free surface at each time step; an image Green function is used in the numerical wave tank so that the integrations on the lateral surfaces and bottom are excluded. The extreme waves are generated by the method of wave focusing. The physical experiments are carried out in a wave flume. On the horizontal velocity of the measured point, numerical solutions agree well with experimental results. The characteristics of the nonlinear extreme-wave kinematics and the velocity distribution are studied here. 展开更多
关键词 numerical wave tank image Green function higher-order boundary element method fully nonlinear extreme wave
下载PDF
An Efficient Model for Transient Surface Waves in Both Finite and Infinite Water Depths 被引量:1
9
作者 宁德志 滕斌 +1 位作者 臧军 柳淑学 《China Ocean Engineering》 SCIE EI 2009年第3期459-472,共14页
A numerical model is developed to simulate fully nonlinear extreme waves in finite and infinite water-depth wave tanks. A semi-mixed Enlerian-Lagrangian formulation is adopted and a higher-order boundary element metho... A numerical model is developed to simulate fully nonlinear extreme waves in finite and infinite water-depth wave tanks. A semi-mixed Enlerian-Lagrangian formulation is adopted and a higher-order boundary element method in conjunction with an image Green function is used for the fluid domain. The botmdary values on the free surface are updated at each time step by a fourth-order Runga-Kutta time-marching scheme at each time step. Input wave characteristics are specified at the upstream boundary by an appropriate wave theory. At the downstream boundary, an artificial damping zone is used to prevent wave reflection back into the computational domain. Using the image Green function in the whole fluid domain, the integrations on the two lateral walls and bottom are excluded. The simulation results on extreme wave elevations in finite and infinite water-depths are compared with experimental results and second-order analytical solutions respectively. The wave kinematics is also discussed in the present study. 展开更多
关键词 focused waves fully nonlinear higher-order boundary element method image Green function infinite water depth
下载PDF
Wave Slamming on An OWSC Wave Energy Converter in Coupled Wave-Current Conditions with Variable-Depth Seabed 被引量:1
10
作者 CHENG Yong JI Chun-yan +1 位作者 YUAN Zhi-ming Atilla INCECIK 《China Ocean Engineering》 SCIE EI CSCD 2021年第5期646-661,共16页
Coastal wave energy resources have enormous exploitation potential due to shorter weather window,closer installation distance and lower maintenance cost.However,impact loads generated by depth variation from offshore ... Coastal wave energy resources have enormous exploitation potential due to shorter weather window,closer installation distance and lower maintenance cost.However,impact loads generated by depth variation from offshore to nearshore and wave-current interaction,may lead to a catastrophic damage or complete destruction to wave energy converters(WECs).This objective of this paper is to investigate slamming response of a coastal oscillating wave surge converter(OWSC)entering or leaving water freely.Based on fully nonlinear potential flow theory,a time-domain wave-current-structure interaction model combined with higher-order boundary element method(HOBEM),is developed to analyze the coupled hydrodynamic problem.The variable-depth seabed is considered in the model to illustrate the shallow water effect on impact loads and free surface profiles in coastal zone.A domain decomposition approach is utilized to simulate the overlapping phenomenon generated by a jet falling into water under gravity effect.Through a series of Lagrangian interpolation methods,the meshes on boundaries are rearranged to avoid the mismatch between element size on free surface and body surface.The present model is validated against the existing experimental and numerical results.Simulations are also provided for the effects of wave-current interaction and uneven local seabed on the slamming responses.It is found that the length of the splash jet increases for a following current and decreases for an opposing current,and that the slamming response of the OWSC device is sensitive to the geometric features of the uneven seabed. 展开更多
关键词 wave-current interaction oscillating wave surge converter fully nonlinear potential flow theory slamming response higher-order boundary element method
下载PDF
WAVE-CURRENT INTERACTIONS WITH THREE-DIMENSIONAL FLOATING BODIES 被引量:15
11
作者 LIU Zhen TENG Bin +1 位作者 NING De-zhi GOU Ying 《Journal of Hydrodynamics》 SCIE EI CSCD 2010年第2期229-240,共12页
A Time-domain Higher-Order Boundary Element Method(THOBEM) is developed for simulating wave-current interactions with 3-D floating bodies.Through a Taylor series expansion and a perturbation procedure,the model is f... A Time-domain Higher-Order Boundary Element Method(THOBEM) is developed for simulating wave-current interactions with 3-D floating bodies.Through a Taylor series expansion and a perturbation procedure,the model is formulated to the first-order in the wave steepness and in the current velocity,respectively.The boundary value problem is decomposed into a steady double-body flow problem and an unsteady wave problem.Higher-order boundary integral equation methods are then used to solve the proposed problems with a fourth-order Runge-Kutta method for the time marching.An artificial damping layer is adopted to dissipate the scattering waves.Different from the other time-domain numerical models,which are often focused on the wave-current interaction with restrained bodies,the present model deals with a floating hemisphere.The numerical results of wave forces,wave run-up and body response are all in a close agreement with those obtained by frequency-domain methods.The proposed numerical model is further applied to investigate wave-current interactions with a floating body of complicated geometry.In this work,the regular and focused wave combined with current interacting with a truss-spar platform is investigated. 展开更多
关键词 wave-current interaction floating bodies time-domain simulation Time-domain higher-order boundary element method(THOBEM)
原文传递
Iterative Rankine HOBEM analysis of hull-form effects in forward-speed diffraction problem 被引量:3
12
作者 何广华 陈丽敏 +1 位作者 张劲生 张世军 《Journal of Hydrodynamics》 SCIE EI CSCD 2017年第2期226-234,共9页
A time-domain numerical algorithm based on the higher-order boundary element method and the iterative time-marching scheme is proposed for seakeeping analysis. The ship waves generated by a hull advancing at a constan... A time-domain numerical algorithm based on the higher-order boundary element method and the iterative time-marching scheme is proposed for seakeeping analysis. The ship waves generated by a hull advancing at a constant forward speed in incident waves and the resultant diffraction forces acting on the hull are computed to investigate the hull-form effects on the hydrodynamic forces. A rectangular computational domain travelling at ship's speed is considered. An artificial damping beach for satisfying the radiation condition is installed at the outer portion of the free surface except the downstream side. An iterative time-marching scheme is employed for updating both kinematic and dynamic free-surface boundary conditions for numerical accuracy and stability. The boundary integral equation is solved by distributing higher-order boundary elements over the wetted body surface and the free surface. The hull-form effects on the naval hydrodynamics are investigated by comparing three different Wigley models. Finally, the corresponding unsteady wave patterns and the wave profiles around the hulls are illustrated and discussed. 展开更多
关键词 Naval hydrodynamics iterative scheme higher-order boundary element method exciting force time domain seakeeping
原文传递
Application of the generalized body-fixed coordinate system for the wave-body interaction problem of a small-depth elastic structure in head seas
13
作者 Kyeonguk Heo Masashi Kashiwagi 《Journal of Hydrodynamics》 SCIE EI CSCD 2021年第6期1255-1270,共16页
The body-fixed coordinate system is applied to the wave-body interaction problem of a small-depth elastic structure which has both rigid and elastic body motions in head waves.In the weakly non-linear assumption,the p... The body-fixed coordinate system is applied to the wave-body interaction problem of a small-depth elastic structure which has both rigid and elastic body motions in head waves.In the weakly non-linear assumption,the perturbation scheme is used and the expansion is conducted up to second-order to consider several non-linear quantities.To solve the boundary value problem,linearization is carried out based not on inertial coordinate but on body-fixed coordinate which could be accelerated by a motion of a body.At first,the main feature of the application of body-fixed coordinate system for a seakeeping problem is briefly described.After that the transformation of a coordinate system is extended to consider an elastic body motion and several physical variables are re-described in the generalized mode.It has been found that the deformation gradient could be used for the transformation of a coordinate system if several conditions are satisfied.Provided there are only vertical bending in elastic modes and the structure has relatively small depth,these conditions are generally satisfied.To calculate an elastic motion of a body,the generalized mode method is adopted and the mode shape is obtained by solving eigen-value problem of dynamic beam equation.In the boundary condition of the body-fixed coordinate system,the motion effect reflected to free-surface boundary is considered by extrapolating each mode shape to the horizontal direction from a body.At last,simple numerical tests are implemented as a validation process.The second-order hydrodynamic force of a freely floating hemisphere is first calculated in zero forward speed condition.Next,motion and added resistance of a ship with forward speed are considered at different flexibility to confirm the effect of an elastic body motion in body-fixed coordinate system. 展开更多
关键词 HYDROELASTICITY higher-order boundary element method(HOBEM) generalized mode method perturbation scheme body-fixed coordinate system wave-body interaction
原文传递
上一页 1 下一页 到第
使用帮助 返回顶部