scholarly journals Hydroelastic wave diffraction by a vertical cylinder

2011 ◽  
Vol 369 (1947) ◽  
pp. 2832-2851 ◽  
Author(s):  
Paul Brocklehurst ◽  
Alexander Korobkin ◽  
Emilian I. Părău
Keyword(s):  
Incident Wave ◽  
Wave Diffraction ◽  
Plate Theory ◽  
Three Dimensional ◽  
Ice Sheet ◽  
Vertical Cylinder ◽  
Finite Depth ◽  
Cylinder Surface ◽  
Linear Elastic ◽  
Potential Flow Model

A linear three-dimensional problem of hydroelastic wave diffraction by a bottom-mounted circular cylinder is analysed. The fluid is of finite depth and is covered by an ice sheet, which is clamped to the cylinder surface. The ice stretches from the cylinder to infinity in all lateral directions. The hydroelastic behaviour of the ice sheet is described by linear elastic plate theory, and the fluid flow by a potential flow model. The two-dimensional incident wave is regular and has small amplitude. An analytical solution of the coupled problem of hydroelasticity is found by using a Weber transform. We determine the ice deflection and the vertical and horizontal forces acting on the cylinder and analyse the strain in the ice sheet caused by the incident wave.

Wave-Current Loading on a Vertical Slender Cylinder by Two Different Numerical Models

2006 ◽  
Author(s):  
M. H. Zaman ◽  
R. E. Baddour
Keyword(s):  
Numerical Models ◽  
Numerical Technique ◽  
Three Dimensional ◽  
Vertical Cylinder ◽  
Finite Depth ◽  
Offshore Structure ◽  
Current Field ◽  
Oblique Wave ◽  
Waves And Currents ◽  
Current Loading

The study of the effects resulting from the interaction of a combined wave-current field with any ocean structure is important for the design and performance evaluation of that structure. The prudent computation of forces exerted by waves and currents is an essential task in the study of the stability of an offshore structure. A study on the loading of an oblique wave and a current field on a fixed vertical slender cylinder in a 3D flow frame is illustrated in Zaman and Baddour (2004). The three dimensional expressions describing the characteristics of the combined wave-current field in terms of mass, momentum and energy flux conservation equations are formulated. The parameters before the interaction of the oblique wave-free uniform current and current-free wave are used to formulate the kinematics of the flow field. These expressions are also employed to formulate and calculate the loads imparted by the wave-current fluid flow on a bottom mounted slender vertical cylinder. In this work a 2D version of the above 3D model called here Model-I has been used for the numerical computations presented in this paper. The second model denoted model-II in the present paper is based on Euler equations. This model is formulated through the vertical integration of the continuity equation and the equations of motions, Zaman et al (1997). A semi-implicit numerical technique is employed for the numerical solution. In the present paper comparisons are made between the results obtained from the 2D version of the above models in finite depth. Both models are then compared with some relevant experimental data. Morison et al equation (1950) is deployed for the load computations in all cases.

scholarly journals Interaction of a Solitary Wave with Vertical Fully/Partially Submerged Circular Cylinders with/without a Hollow Zone

2020 ◽  
Vol 8 (12) ◽  
pp. 1022
Author(s):  
Chih-Hua Chang
Keyword(s):  
Circular Cylinder ◽  
Solitary Wave ◽  
Three Dimensional ◽  
Vertical Cylinder ◽  
Wave Model ◽  
Circular Cylinders ◽  
Cylinder Surface ◽  
Wave Elevation ◽  
Curvilinear Grid ◽  
Nonlinear Potential

In this article, a three-dimensional, fully nonlinear potential wave model is applied based on a curvilinear grid system. This model calculates the wave action on a fully/partially submerged vertical cylinder with or without a hollow zone. As basic verification, a solitary wave hitting a single fully or partially submerged circular cylinder is tested, and our numerical results agree with the experimental results obtained by others. The influence of cylinder immersion depth and size on the wave elevation change on the cylinder surface is considered. The model is also applied to investigate the wave energy of a solitary wave passing through a hollow circular cylinder to determine the effect of the size and draft on the wave oscillating in the hollow zone.

Numerical Simulation of Nonlinear Wave Diffraction by a Vertical Cylinder

1992 ◽  
Vol 114 (1) ◽  
pp. 36-44 ◽  
Author(s):  
C. Yang ◽  
R. C. Ertekin
Keyword(s):  
Experimental Data ◽  
Circular Cylinder ◽  
Nonlinear Wave ◽  
Wave Diffraction ◽  
Three Dimensional ◽  
Vertical Cylinder ◽  
Radiation Condition ◽  
Wave Force ◽  
Second Order ◽  
Time Stepping

A three-dimensional time domain approach is used to study nonlinear wave diffraction by a fixed, vertical circular-cylinder that extends to the sea floor. In this approach, the development of the flow can be obtained by a time-stepping procedure, in which the velocity potential of the flow at any instant of time is obtained by the boundary-element method. In the numerical calculations, the exact body-boundary condition is satisfied on the instantaneous wetted surface of the cylinder, and an extended Sommerfeld condition is developed and used as the numerical radiation condition. The fourth-order Adams-Bashford method is employed in the time stepping scheme. Calculations are done to obtain the nonlinear diffraction of solitary waves and Stokes second-order waves by a vertical circular-cylinder. Numerical results are compared with the available linear and second-order wave-force predictions for some given wave height and wavelength conditions, and also with experimental data. Present horizontal force results agree better with the experimental data than the previous predictions.

scholarly journals Concentrated Loads on a Floating Ice Sheet

1977 ◽  
Vol 19 (81) ◽  
pp. 237-245
Author(s):  
D. E. Nevel
Keyword(s):  
Load Distribution ◽  
Elastic Layer ◽  
Plate Theory ◽  
Three Dimensional ◽  
Ice Sheet ◽  
Integral Form ◽  
Maximum Tensile Stress ◽  
Radial Position ◽  
Ice Thickness ◽  
Concentrated Loads

AbstractThe safe bearing capacity of a floating ice sheet is usually determined by limiting the maximum tensile stress which occurs under the load at the bottom of the ice sheet. If the size of the load distribution is large compared to the ice thickness, the thin plate theory predicts these stresses correctly. However, if the size of the load distribution becomes small compared to the ice thickness, the plate theory overestimates the stresses. In this case the ice sheet should he treated as a three-dimensional elastic layer.Previous investigators have solved the elastic-layer problem for loads distributed over a circular area, and have limited the results to the stress at the bottom of the ice sheet directly under the center of the load. In the present paper the stresses are evaluated at any radial position, and it is shown how these stresses approach those for the plate theory as the radial position becomes large. The solutions for the stresses are presented in integral form, as well as graphs from the numerical integration. These new results are significant for the superposition of stresses when two concentrated loads act near each other.Similarly for loads distributed over a rectangular area, the plate theory will overestimate the stresses if the dimensions of the load becomes small compared to the ice thickness. For this case integral solutions are presented for the stresses, and are evaluated directly under the center of the load.

Combined Loading of a Wave and Surface Current on a Fixed Vertical Slender Cylinder

2005 ◽  
Author(s):  
M. H. Zaman ◽  
R. E. Baddour
Keyword(s):  
Three Dimensional ◽  
Vertical Cylinder ◽  
Surface Current ◽  
Finite Depth ◽  
Combined Loading ◽  
Current Analysis ◽  
Current Field ◽  
3D Flow ◽  
Uniform Current ◽  
Uniform Currents

A study on the loading of an oblique surface wave and a surface current field on a fixed vertical slender cylinder in a 3D flow frame is illustrated in the present paper. The three dimensional expressions describing the characteristics of the combined wave-current field in terms of mass, momentum and energy flux conservation equations are formulated. The parameters before the interaction of the oblique wave-free uniform current and current-free wave are used to formulate the kinematics of the flow field. These expressions are also employed to formulate and calculate the loads imparted by the wave-current fluid flow on a bottom mounted slender vertical cylinder. The surface current considered in this report, is assumed uniform and acting over a layer of fluid that extends from the free surface to a specified finite depth. Prior work assumes that uniform currents existed over the total depth of the fluid domain. In this paper we extend the approach considered in Zaman and Baddour (2004) for the wave-current analysis. Morison et al equation is deployed for the load computations in all cases. The above model is utilized to compute the loads on a slender cylinder for a wave with varying range of incidence current field. Computations of the moments are also done for the case when current is existed over the whole water depth of the domain.

Computations of fully nonlinear three-dimensional wave–wave and wave–body interactions. Part 2. Nonlinear waves and forces on a body

2001 ◽  
Vol 438 ◽  
pp. 41-66 ◽  
Author(s):  
YUMING LIU ◽  
MING XUE ◽  
DICK K. P. YUE
Keyword(s):  
Steady State ◽  
Wave Diffraction ◽  
High Harmonic ◽  
Three Dimensional ◽  
Vertical Cylinder ◽  
Fully Nonlinear ◽  
Bow Wave ◽  
Stokes Waves ◽  
State Force ◽  
Dimensional Wave

The mixed-Eulerian–Lagrangian method using high-order boundary elements, described in Xue et al. (2001) for the simulation of fully nonlinear three-dimensional wave–wave and wave–body interactions, is here extended and applied to the study of two nonlinear three-dimensional wave–body problems: (a) the development of bow waves on an advancing ship; and (b) the steep wave diffraction and nonlinear high-harmonic loads on a surface-piercing vertical cylinder. For (a), we obtain convergent steady-state bow wave profiles for a flared wedge, and the Wigley and Series 60 hulls. We compare our predictions with experimental measurements and find good agreement. It is shown that upstream influence, typically not accounted for in quasi-two-dimensional theory, plays an important role in bow wave prediction even for fine bows. For (b), the primary interest is in the higher-harmonic ‘ringing’ excitations observed and quantified in experiments. From simulations, we obtain fully nonlinear steady-state force histories on the cylinder in incident Stokes waves. Fourier analysis of such histories provides accurate predictions of harmonic loads for which excellent comparisons to experiments are obtained even at third order. This confirms that ‘ringing’ excitations are directly a result of nonlinear wave diffraction.

scholarly journals Concentrated Loads on a Floating Ice Sheet

1977 ◽  
Vol 19 (81) ◽  
pp. 237-245 ◽  
Author(s):  
D. E. Nevel
Keyword(s):  
Load Distribution ◽  
Elastic Layer ◽  
Plate Theory ◽  
Three Dimensional ◽  
Ice Sheet ◽  
Integral Form ◽  
Maximum Tensile Stress ◽  
Radial Position ◽  
Ice Thickness ◽  
Concentrated Loads

Abstract The safe bearing capacity of a floating ice sheet is usually determined by limiting the maximum tensile stress which occurs under the load at the bottom of the ice sheet. If the size of the load distribution is large compared to the ice thickness, the thin plate theory predicts these stresses correctly. However, if the size of the load distribution becomes small compared to the ice thickness, the plate theory overestimates the stresses. In this case the ice sheet should he treated as a three-dimensional elastic layer. Previous investigators have solved the elastic-layer problem for loads distributed over a circular area, and have limited the results to the stress at the bottom of the ice sheet directly under the center of the load. In the present paper the stresses are evaluated at any radial position, and it is shown how these stresses approach those for the plate theory as the radial position becomes large. The solutions for the stresses are presented in integral form, as well as graphs from the numerical integration. These new results are significant for the superposition of stresses when two concentrated loads act near each other. Similarly for loads distributed over a rectangular area, the plate theory will overestimate the stresses if the dimensions of the load becomes small compared to the ice thickness. For this case integral solutions are presented for the stresses, and are evaluated directly under the center of the load.

scholarly journals Wave diffraction by a circular crack in an ice sheet floating on water of finite depth

2018 ◽  
Vol 30 (11) ◽  
pp. 117103 ◽  
Author(s):  
Z. F. Li ◽  
G. X. Wu ◽  
Y. Y. Shi
Keyword(s):  
Wave Diffraction ◽  
Ice Sheet ◽  
Circular Crack ◽  
Finite Depth

Prediction of Ship Motions Via a Three-Dimensional Time-Domain Method Following a Quad-Tree Adaptive Mesh Technique

2020 ◽  
Vol 27 (1) ◽  
pp. 29-38
Author(s):  
Teng Zhang ◽  
Junsheng Ren ◽  
Lu Liu
Keyword(s):  
Free Surface ◽  
Incident Wave ◽  
Time Domain ◽  
Three Dimensional ◽  
Adaptive Mesh ◽  
Wave Profile ◽  
Time Domain Method ◽  
Ship Motions ◽  
Quad Tree ◽  
Mesh Technique

AbstractA three-dimensional (3D) time-domain method is developed to predict ship motions in waves. To evaluate the Froude-Krylov (F-K) forces and hydrostatic forces under the instantaneous incident wave profile, an adaptive mesh technique based on a quad-tree subdivision is adopted to generate instantaneous wet meshes for ship. For quadrilateral panels under both mean free surface and instantaneous incident wave profiles, Froude-Krylov forces and hydrostatic forces are computed by analytical exact pressure integration expressions, allowing for considerably coarse meshes without loss of accuracy. And for quadrilateral panels interacting with the wave profile, F-K and hydrostatic forces are evaluated following a quad-tree subdivision. The transient free surface Green function (TFSGF) is essential to evaluate radiation and diffraction forces based on linear theory. To reduce the numerical error due to unclear partition, a precise integration method is applied to solve the TFSGF in the partition computation time domain. Computations are carried out for a Wigley hull form and S175 container ship, and the results show good agreement with both experimental results and published results.

Sign in / Sign up

Export Citation Format

Share Document