scholarly journals THE EFFECT OF BED SLOPE ON WAVE CHARACTERISTICS

1982 ◽  
Vol 1 (18) ◽  
pp. 36
Author(s):  
R.C. Nelson
Keyword(s):  
Sediment Transport ◽  
Velocity Field ◽  
Wave Theory ◽  
Bed Sediment ◽  
Wave Shape ◽  
Wave Characteristics ◽  
Course Of Action ◽  
Bed Slope ◽  
Wave Induced ◽  
Made In

In all wave theories used in engineering applications it is assumed that the profile of the bed is horizontal which results in a symmetrical wave shape and velocity field, so that, strictly speaking, they can be applied only to this condition. Nearshore bottom profiles are, however, seldom horizontal, and a wave moving over a shoaling slope has an asymmetrical profile which is associated with an asymmetrical velocity field within the wave which, in turn, directly influences the movement of bed sediment. As a matter of necessity, but within reason, engineers have ignored the influence of bed slope on the wave theory used. This course of action was justifiable on many counts, not the least of which was that inaccuracies associated with the theories used were far greater than any inaccuracies introduced by ignoring bed slope parameters. However, wave theories developed in recent years have become increasingly accurate and reliable so that it may now be necessary to take account of bed slope parameters in applying these wave theories before further improvements can be made in the techniques used to predict wave-induced sediment transport.

scholarly journals FIFTH ORDER GRAVITY WAVE THEORY

2011 ◽  
Vol 1 (7) ◽  
pp. 10 ◽  
Author(s):  
Lars Skjelbreia ◽  
James Hendrickson
Keyword(s):  
Theoretical Calculations ◽  
Wave Length ◽  
Wave Theory ◽  
Order Theory ◽  
Wave Characteristics ◽  
Finite Height ◽  
Scientists And Engineers ◽  
Fifth Order ◽  
Horizontal Bottom ◽  
Made In

In dealing with problems connected with gravity waves, scientists and engineers frequently find it necessary to make lengthy theoretical calculations involving such wave characteristics as wave height, wave length, period, and water depth. Several approximate theoretical expressions have been derived relating the above parameters. Airy, for instance, contributed a very valuable and complete theory for waves traveling over a horizontal bottom in any depth of water. Due to the simplicity of the Airy theory, it is frequently used by engineers. This theory, however, was developed for waves of very small heights and is inaccurate for waves of finite height. Stokes presented a similar solution for waves of finite height by use of trigonometric series. Using five terms in the series, this solution will extend the range covered by the Airy theory to waves of greater steepness. No attempt has been made in this paper to specify the range where the theory is applicable. The coefficients in these series are very complicated and for a numerical problem, the calculations become very tedious. Because of this difficulty, this theory would be very little used by engineers unless the value of the coefficient is presented in tabular form. The purpose of this paper is to present the results of the fifth order theory and values of the various coefficients as a function of the parameter d/L.

scholarly journals Influence of Wave Shape on Sediment Transport in Coastal Regions

2018 ◽  
Vol 65 (2) ◽  
pp. 73-90 ◽  
Author(s):  
Rafał Ostrowski
Keyword(s):  
Sediment Transport ◽  
Water Surface ◽  
Wave Motion ◽  
Free Stream ◽  
Theoretical Description ◽  
Wave Shape ◽  
Coastal Regions ◽  
Current Impact ◽  
Wave Induced ◽  
Asymmetric Wave

AbstractThe paper deals with the influence of the wave shape, represented by water surface elevations and wave-induced nearbed velocities, on sediment transport under joint wave-current impact. The focus is on the theoretical description of vertically asymmetric wave motion and the effects of wave asymmetry on net sediment transport rates during interaction of coastal steady currents, namely wave-driven currents, with wave-induced unsteady free stream velocities. The cross-shore sediment transport is shown to depend on wave asymmetry not only quantitatively (in terms of rate), but also qualitatively (in terms of direction). Within longshore lithodynamics, wave asymmetry appears to have a significant effect on the net sediment transport rate.

An Experimental Study on the Wave-Induced Topographic Change in Artificial Shallows: Focusing on the Effects of Pore-Water Pressure on Sediment Transport

2014 ◽  
Vol 56 (2) ◽  
pp. 1450008-1-1450008-21 ◽  
Author(s):  
Tomoaki Nakamura ◽  
Yuta Nezasa ◽  
Yong-Hwan Cho ◽  
Ryo Ishihara ◽  
Norimi Mizutani
Keyword(s):  
Experimental Study ◽  
Sediment Transport ◽  
Pore Water ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Wave Induced

Effects of Cnoidal Wave-Induced Seepage on Vertical Breakwater Resting on Permeable Elastic Seabed

2014 ◽  
Vol 716-717 ◽  
pp. 284-288
Author(s):  
Jian Kang Yang ◽  
Hua Huang ◽  
Lin Guo ◽  
Jing Rong Lin ◽  
Qing Yong Zhu ◽  
...  
Keyword(s):  
Shallow Water ◽  
Wave Theory ◽  
Cnoidal Wave ◽  
Load Prediction ◽  
Wave Load ◽  
Seepage Pressure ◽  
Theoretical Investigations ◽  
Nonlinearity Effect ◽  
Wave Nonlinearity ◽  
Wave Induced

Theoretical investigations on cnoidal waves interacting with breakwater resting on permeable elastic seabed are presented in this paper. Based on the shallow water reflected wave theory and Biot consolidation theory on wave-induced seepage pressure, the analytical solutions to first order cnoidal wave reflection and wave-induced seepage pressure are obtained by the eigenfunction expansion approach. Numerical results are presented to show the effects of depth of water, breakwater geometry on cnoidal wave-induced seepage uplift force and overturning moment. Compared with Airy wave theory, in certain shallow water conditions, the shallow water wave theory can more effectively illustrate wave nonlinearity effect in wave load prediction.

Further Discussion on the White-Noise Approach for Predicting Slow-Drifts in FAST

2018 ◽  
Author(s):  
Lucas H. S. do Carmo ◽  
Ewerton C. Camargo ◽  
Alexandre N. Simos
Keyword(s):  
White Noise ◽  
Previous Analysis ◽  
Simple Procedure ◽  
Frequency Domain Analysis ◽  
Common Procedure ◽  
Slow Drift ◽  
Detailed Evaluation ◽  
The Subject ◽  
Wave Induced ◽  
Made In

Making use of theoretical approximations for the computation of the wave-induced slow-drift forces is a common procedure in the early stages of design of a new floating unit. They can help reducing the computational burden in two different fronts: for generating the QTFs in a frequency domain analysis, and during the subsequent execution of time-domain simulations. In a previous paper, we have discussed a simple procedure for making use of the white-noise approximation in FAST, without the need for any modification of the software. The proposal only requires restricting the computation of the QTFs to pairs of frequencies that are indeed essential to the slow-drift dynamics. For this, however, an additional assumption is made, considering that each motion is decoupled from those in the other dofs. In the present paper, a more detailed analysis of the subject is made, in order to clarify the theoretical aspects of the procedure and supplement the previous analysis. Once again, the results are based on the data available for the OC4 FOWT. The accuracy obtained with the procedure is discussed not only in terms of the resulting motions, but also comparing its effects on the second-order force spectra. A more detailed evaluation of the dynamic couplings is presented, and comparisons with the results obtained with Newman’s approximation are made in simulations involving waves only.

scholarly journals ПРЕДПРИНИМАТЕЛЬСКИЕ РИСКИ В РК

2021 ◽  
Author(s):  
М. Т. Баймолдаева ◽  
◽  
Н. К. Абдигалиева ◽  
Keyword(s):  
Entrepreneurial Activity ◽  
Entire System ◽  
Course Of Action ◽  
Market Relations ◽  
Made In

It is legally established that entrepreneurial activity is risky, that is, the actions of entrepreneurs in the conditions of established market relations, competition, the functioning of the entire system of economic laws cannot be calculated and implemented with complete certainty. Many decisions in entrepreneurial activity have to be made in conditions of uncertainty, when it is necessary to choose a course of action from several possible options, the implementation of which is difficult to predict.

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