scholarly journals EXPERIMENTAL INVESTIGATIONS OF PERIODIC WAVES NEAR BREAKING

1980 ◽  
Vol 1 (17) ◽  
pp. 14 ◽  
Author(s):  
J. Buhr Hansen
Keyword(s):  
Wave Height ◽  
Water Depth ◽  
Wave Length ◽  
Experimental Investigations ◽  
Periodic Waves ◽  
Wave Energy Flux ◽  
Surface Profiles ◽  
Series Of Experiments ◽  
Sloping Beach ◽  
Theory And Experiments

The results presented are from a series of experiments of periodic waves approaching breaking on a gently sloping beach. The recorded surface profiles are compared with a cnoidal theory taking into account the effect of the bottom slope. In both theory and experiments a skewness of the profile is observed. A fair agreement is found within certain limits of the wave height to water depth ratio and when the slope is sufficiently gentle. The change in water depth over a wave length must be sufficiently small. The detailed analysis of the surface profiles including the skewness element shows good agreement with the cnoidal theory in cases where the wave height variation is as predicted by cnoidal wave shoaling. The recorded surface profiles together with the recorded phase velocities are further used in computing the wave energy flux based on the theoretical relations from linear and cnoidal theories. Reasonable constancy is observed over the whole length covered by the experiments. Finally the recorded wave set-down is compared with the results of linear and cnoidal theories. When approaching breaking neither of the theories can apparently predict the recorded water level changes.

scholarly journals DEFORMATION UP TO BREAKING OF PERIODIC WAVES ON A BEACH

1976 ◽  
Vol 1 (15) ◽  
pp. 26 ◽  
Author(s):  
Ib A. Svendson ◽  
J. Buhr Hansen
Keyword(s):  
Wave Height ◽  
Water Depth ◽  
Wave Length ◽  
Empirical Relation ◽  
Breaking Point ◽  
Periodic Waves ◽  
Depth Ratio ◽  
Surface Profiles ◽  
Deep Water Wave ◽  
Sloping Beach

An experimental description is presented for 'the transformation of periodic waves which approach breaking on a gently sloping beach. The data include the variation of wave height, phase velocity, wave surface profiles, and the maximum value of the wave height to water depth ratio (H/h)max around the breaking point. The results are compared with the theories of sinusoidal and cnoidal wave shoaling, and the latter is shown in most cases to agree remarkably well when the laminar energy loss along the walls and bottom of the wave tank is included. An empirical relation is established between wave length to water depth ratio L/h at the breaking point and the deep water wave steepness H0/L0. Also the maximum wave height to water depth ratio at breaking shows considerably less scattering than found previously, when plotted versus S = hx L/h, hx being bottom slope.

scholarly journals THE SOLITARY WAVE: ITS CELERITY, PROFILE, INTERNAL VELOCITIES AND AMPLITUDE ATTENUATION IN A HORIZONTAL SMOOTH CHANNEL

2000 ◽  
Vol 1 (3) ◽  
pp. 2 ◽  
Author(s):  
James W. Daily ◽  
Samuel C. Stephan, Jr.
Keyword(s):  
Solitary Wave ◽  
Wave Height ◽  
Water Depth ◽  
Wave Length ◽  
Horizontal Displacement ◽  
Smooth Channel ◽  
Amplitude Attenuation ◽  
Oscillatory Waves

The solitary wave consists of a single elevation of water above the originally undisturbed level as shown in Figure 1. It is translatory, a passing wave causing a definite net horizontal displacement of the liquid. While the characteristics of oscillatory waves depend on wave length as well as wave height and water depth, the solitary wave is apparently described completely by the wave height and water depth so long as attenuation due to friction is unimportant.

scholarly journals THE MEASURED PROPERTIES OF IRREGULAR WAVE BREAKING AND WAVE HEIGHT CHANGE AFTER BREAKING ON THE SLOPE

1988 ◽  
Vol 1 (21) ◽  
pp. 29 ◽  
Author(s):  
Akira Seyama ◽  
Akira Kimura
Keyword(s):  
Wave Height ◽  
Water Depth ◽  
Wave Theory ◽  
Irregular Waves ◽  
Linear Wave ◽  
Periodic Waves ◽  
Zero Crossing ◽  
Irregular Wave ◽  
Height Change ◽  
Cross Waves

Wave height change of the zero-down-cross waves on uniform slopes were examined experimentally. The properties of shoaling, breaking and decay after breaking for a total of about 4,000 irregular waves of the Pierson-Moskowitz type on 4 different slopes (1/10, 1/20, 1/30 and 1/50) were investigated. The shoaling property of the zero-down-cross waves can be approximated by the linear wave theory. However, the properties of breaking and decay after breaking differ considerably from those for periodic waves. The wave height water depth ratio (H/d) at the breaking point for the zero-down-cross waves is about 30% smaller than that for periodic waves on average despite the slopes. Wave height decay after breaking also differs from that for periodic waves and can be classified into three regions, i.e. shoaling, plunging and bore regions. Experimental equations for the breaking condition and wave height change after breaking are proposed in the study. A new definition of water depth for the zero-crossing wave analysis which can reduce the fluctuation in the plotted data is also proposed.

scholarly journals RESEARCHES ON DOUBLE CURTAIN WALL BREAKWATER

1966 ◽  
Vol 1 (10) ◽  
pp. 51
Author(s):  
Shigeru Tanaka
Keyword(s):  
Wave Height ◽  
Water Depth ◽  
High Speed ◽  
Wave Length ◽  
High Tide ◽  
North Coast ◽  
Curtain Wall ◽  
Remarkable Effect ◽  
The North ◽  
Sea Bottom

It has been clarified by some researchers(R. L. Wiegel1 , F. Ursell", R. Morihira & S. Anezaki3), etc.) that the single curtain wall breakwater has no good wave-dissipating effect at the usual coastal area where the ratio of water-depth to wave-length is considerably small. The author has made researches concerning "Multiple Curtain Wall Breakwater", anticipating the supposition that it may be very effective for the dissipation of wave energy even at a shallow coastal zone, because of its peculiar effectiveness upon wave dissipation. Double curtain wall breakwater is composed of two parallel rows of curtain walls attached to the supporting props installed at an adequate interval. The interval of the said two rows is very important, and the determination of a proper interval, relating to a high wind wave having a definite length and a definite wave height, is one of the main objects of this research. These researches were mainly made experimentally. At first the author assumed that the design wave had the period of 5-6 sec, the length of 50 - 60 m and the height of 1.5 m. The results of the model experiment show that the double curtain wall breakwater, installed at the depth ranging 3 - 10 m, has remarkable effect on wave dissipation.Secondly the author selected a particular location on the north coast of Osaka Bay where the design wave has the period of 7 - 9 sec, the wave length of 65 - 70 m and the wave height of 3.8 - 4.0 m at offshore. At the expected site of thebreakwater, the sea bottom is flat and nearly horizontal, and the water depth under the condition of the extraordinary high tide is 10.5 m above the sea bottom, and an experiment was carried out by the model for this location. One kind of model was constructed in a shallow basin of 0.5 m x 25 m x 30 m, in the scale of 1 to 40 and of 1 to 70, in order to determine its transmission coefficient of wave height. Another kind of model was made in a glazed steel frame tank of 1.6 mx 1.8 m x 28 m, equipped with a piston type wave generator operated by 5 HP motor. The scale of this model is 1 to 10, and its purpose is to secure the surface disturbance and to trace the trajectories of small suspended particles by a 16 mm cine camera and a high speed motion camera.

Wear Model for Piston Ring and Cylinder Bore System

2005 ◽  
Author(s):  
Yunchao Qiu ◽  
Qian Zou ◽  
Gary C. Barber ◽  
Harold E. McCormick ◽  
Dequan Zou ◽  
...  
Keyword(s):  
Piston Ring ◽  
Thickness Distribution ◽  
Matrix Ring ◽  
Experimental Investigations ◽  
General Tendency ◽  
Wear Model ◽  
Wear Process ◽  
The Matrix ◽  
Surface Profiles ◽  
Cylinder Bore

A new wear model for piston ring and cylinder bore system has been developed to predict wear process with high accuracy and efficiency. It will save time and cost compared with experimental investigations. Surfaces of ring and bore were divided into small domains and assigned to corresponding elements in two-dimensional matrix. Fast Fourier Transform (FFT) and Conjugate Gradient Method (CGM) were applied to obtain pressure distribution on the computing domain. The pressure and film thickness distribution were provided by a previously developed ring/bore lubrication module. By changing the wear coefficients of the ring and bore with accumulated cycles, wear was calculated point by point in the matrix. Ring and bore surface profiles were modified when wear occurred. The results of ring and bore wear after 1 cycle, 10 cycles and 2 hours at 3600 rpm were calculated. They coincided well with the general tendency of wear in a ring and bore system.

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

scholarly journals An attempt to determine the adiabatic relations of ethyl oxide

1897 ◽  
Vol 60 (359-367) ◽  
pp. 336-337 ◽  
Keyword(s):  
Wave Length ◽  
Experimental Results ◽  
Mathematical Discussion ◽  
Series Of Experiments

The wave-length of sound in gaseous and in liquid ethyl oxide (sulphuric ether) has been determined by the two first-mentioned of the authors, by means of Kundt’s method, between limits of temperature ranging from 100° C. to 200° C., and of pressure ranging from 4000 mm. to 31,000 mm. of mercury, and of volume ranging from 2·6 c. c, per gram to 71 c. c. per gram. Making use of the same apparatus throughout, the results obtained are to be regarded as comparative, and, by careful determination of the pitch of the tone transmitted through the gas, it is probable they are approximately absolute. The sections of the complete memoir deal with (I) a description of the apparatus employed, (II) the method of ascertaining the weights of ether used in each series of experiments, (III) determinations of the frequency of the vibrating rod, (IV) the calculations of the adiabatic elasticity and tables of the experimental results, and (V) a mathematical discussion of the results. The last section is due to Mr. Rose-Innes.

scholarly journals MEASURING DISPLACEMENT AND VELOCITY OF A STRIKER USING A RADIO-INTERFEROMETER

2019 ◽  
Vol 81 (1) ◽  
pp. 118-128
Author(s):  
V. V. Balandin ◽  
V. V. Balandin ◽  
V. V. Parkhachev
Keyword(s):  
High Speed ◽  
Radio Interferometer ◽  
Experimental Investigations ◽  
X Ray ◽  
Gas Gun ◽  
Impact Interaction ◽  
Ballistic Experiment ◽  
Wide Range ◽  
Series Of Experiments ◽  
Error Of Measurement

Investigating impact interaction of solid and deformed bodies with obstacles of various physical natures requires developing experimental methodologies of registering the parameters of the interaction process. In experimental investigations of impact interaction of solids, it is common practice to measure displacement of strikers as a function of time, as well as their velocity and deceleration. To determine the displacement and velocity of a striker, a radio-interferometric methodology of registering the displacement of its rear end is proposed. In contrast with the registration methods based on high-speed filming and pulsed X-ray photography, the method using a millimeter-range radio-interferometer provides continuous high-accuracy registering of the displacement of the rear end of a striker in a wide range of displacement values. To test the effectiveness of the methodology, a series of experiments have been conducted on registering the motion of a cylindrical striker of an aluminum alloy, fired from a 20mm-dia gas gun. The displacement of the striker was also monitored using high-speed filming. The results of measuring using the two methodologies differ within the limits of the error of measurement. Based on the results of the above experiments, it has been concluded that the methodology of determining the displacement and velocity of strikers in a ballistic experiment using a mm-range radio-interferometer makes it possible to measure practically continuously large displacements (100 mm and larger) to a safe accuracy. The present methodology can be used for measuring the displacement and velocity of the rear end of a striker interacting with obstacles of various physical natures (metals, ceramics, soils, concretes, etc.).

scholarly journals Experimental investigations of CO2 seepage behaviorin naturally fractured coal under hydro-thermal-mechanical conditions

2021 ◽  
Vol 25 (6 Part B) ◽  
pp. 4651-4658
Author(s):  
Teng Teng ◽  
Xiaoyan Zhu ◽  
Yu-Ming Wang ◽  
Chao-Yang Ren
Keyword(s):  
Gas Flow ◽  
Confining Pressure ◽  
Gas Pressure ◽  
Experimental Investigations ◽  
Permeability Evolution ◽  
Coal Permeability ◽  
Naturally Fractured ◽  
Series Of Experiments ◽  
Fractured Coal ◽  
Increasing Temperature

Gas-flow in coal or rock is hypersensitive to the changes of temperature, confin?ing pressure and gas pressure. This paper implemented a series of experiments to observe the seepage behavior, especially the permeability evolution of CO2 in naturally fractured coal sample under coupled hydro-thermal-mechanical conditions. The experimental results show that coal permeability increases exponentially with the increasing gas pressure, and tends to be linear when the confining pressure is high. Coal permeability decreases exponentially with the increasing confining pressure. Coal permeability decreases with the increasing temperature generally, but it may bounce up when the temperature rises to high. The results provide reference for the projects of coal gas extraction and carbon dioxide geological sequestration.

scholarly journals Wave Interaction with Single and Twin Vertical and Sloped Slotted Walls

2020 ◽  
Vol 8 (8) ◽  
pp. 589
Author(s):  
Mohamad Alkhalidi ◽  
Noor Alanjari ◽  
S. Neelamani
Keyword(s):  
Energy Dissipation ◽  
Transmission Coefficient ◽  
Wave Height ◽  
Wave Reflection ◽  
Wave Length ◽  
Wave Interaction ◽  
Wave Transmission ◽  
Random Wave ◽  
Dissipation Coefficient ◽  
Energy Dissipation Coefficient

The interaction between waves and slotted vertical walls was experimentally studied in this research to examine the performance of the structure in terms of wave transmission, reflection, and energy dissipation. Single and twin slotted barriers of different slopes and porosities were tested under random wave conditions. A parametric analysis was performed to understand the effect of wall porosity and slope, the number of walls, and the incoming relative wave height and period on the structure performance. The main focus of the study was on wave transmission, which is the main parameter required for coastal engineering applications. The results show that reducing wall porosity from 30% to 10% decreases the wave transmission by a maximum of 35.38% and 38.86% for single and twin walls, respectively, increases the wave reflection up to 47.6%, and increases the energy dissipation by up to 23.7% on average for single walls. For twin-walls, the reduction in wall porosity decreases the wave transmission up to 26.3%, increases the wave reflection up to 40.5%, and the energy dissipation by 13.3%. The addition of a second wall is more efficient in reducing the transmission coefficient than the other wall parameters. The reflection and the energy dissipation coefficients are more affected by the wall porosity than the wall slope or the existence of a second wall. The results show that as the relative wave height increases from 0.1284 to 0.2593, the transmission coefficient decreases by 21.2%, the reflection coefficient decreases by 15.5%, and the energy dissipation coefficient increases by 18.4% on average. Both the transmission and the reflection coefficients increase as the relative wave length increases while the energy dissipation coefficient decreases. The variation in the three coefficients is more significant in deep water than in shallower water.

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