scholarly journals DEVELOPMENT OF SHIP WAVE DESIGN INFORMATION

1984 ◽  
Vol 1 (19) ◽  
pp. 216 ◽  
Author(s):  
Robert M. Sorensen ◽  
J. Richard Weggel
Keyword(s):  
Wave Height ◽  
Water Depth ◽  
Additional Data ◽  
Prediction Methods ◽  
Ship Wave ◽  
Wave Prediction ◽  
Laboratory Investigations ◽  
Predictor Model ◽  
The Waves ◽  
Ship Speed

During the last three decades several field and laboratory investigations have been conducted in which the waves generated by a wide variety of vessels have been measured. There is a need to synthesize the data published from these studies and to develop general ship wave prediction methods for designers. To complete this task some additional ship wave data must be collected. This paper initiates the effort to develop these prediction methods. A summary and critique of available data are given. Then, the appropriate portion of these data is employed to develop a ship wave height predictor model that gives the maximum ship wave height as a function of ship speed and displacement, water depth, and distance from the sailing line. This is an interim model that is quite applicable but can be improved pending additional data. Finally, planned future efforts to further develop design wave prediction methods are discussed.

LARGE SCALE EXPERIMENTS ON EVOLUTION AND RUN-UP OF BREAKING SOLITARY WAVES

2007 ◽  
Vol 01 (03) ◽  
pp. 257-272 ◽  
Author(s):  
KAO-SHU HWANG ◽  
YU-HSUAN CHANG ◽  
HWUNG-HWENG HWUNG ◽  
YI-SYUAN LI
Keyword(s):  
Solitary Wave ◽  
Wave Height ◽  
Solitary Waves ◽  
Water Depth ◽  
Large Scale ◽  
Scale Effects ◽  
Wave Heights ◽  
Run Up ◽  
Hydraulics Laboratory ◽  
The Waves

The evolution and run-up of breaking solitary waves on plane beaches are investigated in this paper. A series of large-scale experiments were conducted in the SUPER TANK of Tainan Hydraulics Laboratory with three plane beaches of slope 0.05, 0.025 and 0.017 (1:20, 1:40 and 1:60). Solitary waves of which relative wave heights, H/h0, ranged from 0.03 to 0.31 were generated by two types of wave-board displacement trajectory: the ramp-trajectory and the solitary-wave trajectory proposed by Goring (1979). Experimental results show that under the same relative wave height, the waveforms produced by the two generation procedures becomes noticeably different as the waves propagate prior to the breaking point. Meanwhile, under the same relative wave height, the larger the constant water depth is, the larger the dimensionless run-up heights would be. Scale effects associated with the breaking process are discussed.

scholarly journals Ship generated mini-tsunamis

2017 ◽  
Vol 816 ◽  
pp. 142-166 ◽  
Author(s):  
John Grue
Keyword(s):  
Asymptotic Analysis ◽  
Shallow Water ◽  
Wave Height ◽  
Long Waves ◽  
Qualitative Explanation ◽  
The Waves ◽  
Water Speed ◽  
Shallow Water Depth ◽  
Ship Speed ◽  
Good Agreement

Very long waves are generated when a ship moves across an appreciable depth change $\unicode[STIX]{x0394}h$ comparable to the average and relatively shallow water depth $h$ at the location, with $\unicode[STIX]{x0394}h/h\simeq 1$. The phenomenon is new and the waves were recently observed in the Oslofjord in Norway. The 0.5–1 km long waves, extending across the 2–3 km wide fjord, are observed as run-ups and run-downs along the shore, with periods of 30–60 s, where a wave height up to 1.4 m has been measured. The waves travelling with the shallow water speed, found ahead of the ships moving at subcritical depth Froude number, behave like a mini-tsunami. A qualitative explanation of the linear generation mechanism is provided by an asymptotic analysis, valid for $\unicode[STIX]{x0394}h/h\ll 1$ and long waves, expressing the generation in terms of a pressure impulse at the depth change. Complementary fully dispersive calculations for $\unicode[STIX]{x0394}h/h\simeq 1$ document symmetries of the waves at positive or negative $\unicode[STIX]{x0394}h$. The wave height grows with the ship speed $U$ according to $U^{n}$ with $n$ in the range 3–4, for $\unicode[STIX]{x0394}h/h\simeq 1$, while the growth in $U$ is only very weak for $\unicode[STIX]{x0394}h/h\ll 1$ (the asymptotics). Calculations show good agreement with observations.

Surf zone transformation of wave height to water depth ratios

1992 ◽  
Vol 17 (1-2) ◽  
pp. 49-70 ◽  
Author(s):  
R.C. Nelson ◽  
J. Gonsalves
Keyword(s):  
Wave Height ◽  
Water Depth ◽  
Surf Zone

Forced oscillation experiments

1991 ◽  
Vol 334 (1634) ◽  
pp. 199-211
Keyword(s):  
Numerical Methods ◽  
Water Depth ◽  
Forced Oscillation ◽  
Vertical Plane ◽  
Forced Oscillations ◽  
Hydrodynamic Characteristics ◽  
Scale Models ◽  
Ship Speed

Forced oscillation experiments with scale models are carried out to determine hydrodynamic characteristics of ships, with respect to motions in waves or steering and manoeuvring qualities. Depending on the considered motion components, in a horizontal or vertical plane, various methods are used to induce forced oscillations which are discussed briefly. Some results of forced oscillation experiments are presented as examples of this technique and compared with calculations based on numerical methods. The comparisons include, among others, the effects of ship speed and restricted water depth.

scholarly journals APPLICATIONS ON NONLINEAR WAVE COMBINATION

1986 ◽  
Vol 1 (20) ◽  
pp. 26
Author(s):  
J.T. Juang
Keyword(s):  
Wave Height ◽  
Taiwan Strait ◽  
Western Coast ◽  
Linear Wave ◽  
Wave System ◽  
Height Distribution ◽  
Wave Height Distribution ◽  
Local Wave ◽  
Source Wave ◽  
The Waves

Due to the special bathymetry in Taiwan Strait, the waves off the western coast of Taiwan are considered to be composed of two-source wave system. One propagates from the central part of the Strait named main wave, and the other is generated by the local wind known as local wave which occurs along the shore. After the combination and the transformation procedure from these two-nonlinear-source wave system, the wave height distribution in Taiwan Strait should be modified. A comparison of the wave height distributions based on the present proposed method with the field data indicates that the present method yields a better result than other theorems. Furthermore, the result of application of two non-linear wave theorem to wave prediction are also presented.

scholarly journals MACH-REFLECTION AS A DIFFRACTION PROBLEM

1976 ◽  
Vol 1 (15) ◽  
pp. 45 ◽  
Author(s):  
Udo Berger ◽  
Soren Kohlhase
Keyword(s):  
Wave Height ◽  
Incident Wave ◽  
Water Waves ◽  
Gas Dynamics ◽  
Mach Reflection ◽  
Diffraction Problem ◽  
Vertical Wall ◽  
Oblique Wave ◽  
Wave Heights ◽  
The Waves

As under oblique wave approach water waves are reflected by a vertical wall, a wave branching effect (stem) develops normal to the reflecting wall. The waves progressing along the wall will steep up. The wave heights increase up to more than twice the incident wave height. The £jtudy has pointed out that this effect, which is usually called MACH-REFLECTION, is not to be taken as an analogy to gas dynamics, but should be interpreted as a diffraction problem.

A Slender-Ship Theory of Wave Resistance

1983 ◽  
Vol 27 (01) ◽  
pp. 13-33
Author(s):  
Francis Noblesse
Keyword(s):  
Froude Number ◽  
Wave Resistance ◽  
Successive Approximations ◽  
Zeroth Order ◽  
Remarkable Effect ◽  
Ship Wave ◽  
First Order ◽  
Wigley Hull ◽  
Low Froude Number ◽  
The Waves

A new slender-ship theory of wave resistance is presented. Specifically, a sequence of explicit slender-ship wave-resistance approximations is obtained. These approximations are associated with successive approximations in a slender-ship iterative procedure for solving a new (nonlinear integro-differential) equation for the velocity potential of the flow caused by the ship. The zeroth, first, and second-order slender-ship approximations are given explicitly and examined in some detail. The zeroth-order slender-ship wave-resistance approximation, r(0) is obtained by simply taking the (disturbance) potential, ϕ, as the trivial zeroth-order slender-ship approximation ϕ(0) = 0 in the expression for the Kochin free-wave amplitude function; the classical wave-resistance formulas of Michell [1]2 and Hogner [2] correspond to particular cases of this simple approximation. The low-speed wave-resistance formulas proposed by Guevel [3], Baba [4], Maruo [5], and Kayo [6] are essentially equivalent (for most practical purposes) to the first-order slender-ship low-Froude-number approximation, rlF(1), which is a particular case of the first-order slender-ship approximation r(1): specifically, the first-order slender-ship wave-resistance approximation r(1) is obtained by approximating the potential ϕ in the expression for the Kochin function by the first-order slender-ship potential ϕ1 whereas the low-Froude-number approximation rlF(1) is associated with the zero-Froude-number limit ϕ0(1) of the potentialϕ(1). A major difference between the first-order slender-ship potential ϕ(1) and its zero-Froude-number limit ϕ0(1) resides in the waves that are included in the potential ϕ(1) but are ignored in the zero-Froude-number potential ϕ0(1). Results of calculations by C. Y. Chen for the Wigley hull show that the waves in the potential ϕ(1) have a remarkable effect upon the wave resistance, in particular causing a large phase shift of the wave-resistance curve toward higher values of the Froude number. As a result, the first-order slender-ship wave-resistance approximation in significantly better agreement with experimental data than the low-Froude-number approximation rlF(1) and the approximations r(0) and rM.

Maneuvering Simulation of Two Ships During Meeting and Passing

2014 ◽  
Vol 69 (7) ◽  
Author(s):  
Koki Kitagawa ◽  
Masaaki Sano ◽  
Hironori Yasukawa
Keyword(s):  
Water Depth ◽  
Panel Method ◽  
Time Step ◽  
Interaction Forces ◽  
Motion Equations ◽  
Close Proximity ◽  
External Forces ◽  
Ship Speed

Motion equations of two ships maneuvering in close proximity are solved in consideration of the interaction between hulls. The interaction forces are calculated by a 3D panel method as a function of the ship position in the time step and considered as external forces in maneuvering. Four kinds of ships are prepared and the maneuvering motions are simulated with variation of the combination of ships, water depth, ship speed and draft. The effect of those parameters on the interaction forces and two ships behaviors are investigated. 

Statistical Analysis of a Set of Basin Waves

2011 ◽  
Author(s):  
Jule Scharnke ◽  
Janou Hennig
Keyword(s):  
Statistical Analysis ◽  
Wave Height ◽  
Water Depth ◽  
Water Waves ◽  
Rayleigh Distribution ◽  
Second Order ◽  
Distribution Functions ◽  
Wave Crest ◽  
Intermediate Water ◽  
Wave Measurements

In a recent paper the effect of variations in calibrated wave parameters on wave crest and height distributions was analyzed (OMAE2010-20304, [1]). Theoretical distribution functions were compared to wave measurements with a variation in water depth, wave seed (group spectrum) and location of measurement for the same initial power spectrum. The wave crest distribution of the shallow water waves exceeded both second-order and Rayleigh distribution. Whereas, in intermediate water depth the measured crests followed the second order distribution. The distributions of the measured waves showed that different wave seeds result in the same wave height and crest distributions. Measured wave heights were lower closer to the wave maker. In this paper the results of the continued statistical analysis of basin waves are presented with focus on wave steepness and their influence on wave height and wave crest distributions. Furthermore, the sampling variability of the presented cases is assessed.

Experimental study on the wave height distribution of wind-induced waves in the growth stage under finite water depth

2019 ◽  
Vol 19 (8) ◽  
pp. 2270-2279
Author(s):  
Ang Gao ◽  
Shiqiang Wu ◽  
Li Chen ◽  
Sien Liu ◽  
Zhun Xu ◽  
...  
Keyword(s):  
Wave Height ◽  
Water Depth ◽  
Growth Stage ◽  
Wind Wave ◽  
Model Parameters ◽  
Height Distribution ◽  
Distribution Models ◽  
Wave Height Distribution ◽  
Comparison Results ◽  
Optimized Model

Abstract With the method of a wind tank experiment, the real scenario of lakes with horizontal and vertical circulation of wind-induced flows is considered, and the features of wind wave height and its distribution in the different conditions of wind blowing distance, wind speed and water depth are studied systematically. Afterwards, comparison of the wave height distributions derived directly from experiment and the typical wave height distribution models show that some defects exist in typical wave height distribution models when describing wind wave height distribution in the wave growth stage. On this basis, we propose a new distribution model which is suitable for the description of wind wave height during the growth stage, and the model parameters are acquired with the programming solution method. Finally, the model is further optimized by relating B to σa, and Hs to σa. Comparison results of the optimized model and the typical ones show that the optimized model has advantages in calculation accuracy and convenience of use.

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