A study of the stability of dynamically stable breakwaters

1991 ◽  
Vol 18 (6) ◽  
pp. 916-925 ◽  
Author(s):  
K. R. Hall ◽  
Joseph S. Kao
Keyword(s):  
Research Laboratory ◽  
Coastal Engineering ◽  
Irregular Waves ◽  
Two Dimensional ◽  
Uniformity Coefficient ◽  
Engineering Research ◽  
Hydraulic Models ◽  
Wave Flume ◽  
The Stability ◽  
Dimensional Wave

The effect of gradation of armour stones and the amount of rounded stones in the armour on dynamically stable breakwaters was assessed in a two-dimensional wave flume. A total of 52 series of tests were undertaken at the Coastal Engineering Research Laboratory of Queen's University, Kingston, Canada using irregular waves. Profiles of the structure during the various stages of reshaping were measured using a semiautomatic profiler developed for this study. Four gradations of armour stones were used, giving a range in uniformity coefficient of 1.35–5.4. The volume of stones and the initial berm width required for the development of a stable profile, along with the extent to which the toe of the structure progressed seaward, were chosen as representative parameters of the reshaped breakwater. The results indicated that the toe width formed as a result of reshaping and the area of stones required for reshaping were dependent on the gradation of the armour stones. The initial berm width required for reshaping was also found to be dependent on the gradation and the percentage of rounded stones in the armour. Key words: breakwaters, dynamic stability, hydraulic models, stability, armour stones.

scholarly journals SIMILARITY OF EQUILIBRIUM BEACH PROFILES

1972 ◽  
Vol 1 (13) ◽  
pp. 61 ◽  
Author(s):  
M.J. Paul ◽  
J.W. Kamphuis ◽  
A. Brebner
Keyword(s):  
Long Range ◽  
Scale Effect ◽  
Research Laboratory ◽  
Scaling Laws ◽  
Coastal Engineering ◽  
Two Dimensional ◽  
Engineering Research ◽  
Mobile Bed ◽  
Beach Processes ◽  
Distorted Model

In the design of mobile bed coastal models it is inherently assumed that prototype beach processes may be modelled using lightweight sediment. At the Queen's University Coastal Engineering Research Laboratory, a long range project is currently in progress to determine scaling laws and scale effect for mobile bed coastal models. A large portion of this program is directly concerned with beach profiles and in this paper preliminary work is reported, in which a comparison is made between two dimensional laboratory beach profiles obtained from controlled "prototype", undistorted model and some distorted model tests.

scholarly journals On the Stability of Evolution Galerkin Schemes Applied to a Two‐Dimensional Wave Equation System

2006 ◽  
Vol 44 (4) ◽  
pp. 1556-1583 ◽  
Author(s):  
M. Lukáčová‐Medviďová ◽  
G. Warnecke ◽  
Y. Zahaykah
Keyword(s):  
Wave Equation ◽  
Equation System ◽  
Two Dimensional ◽  
The Stability ◽  
Dimensional Wave

The development of three-dimensional wave-packets in unbounded parallel flows

1968 ◽  
Vol 32 (4) ◽  
pp. 801-808 ◽  
Author(s):  
M. Gaster ◽  
A. Davey
Keyword(s):  
Wave Packet ◽  
Three Dimensional ◽  
Two Dimensional ◽  
Mean Flow ◽  
Physical Plane ◽  
Parallel Flows ◽  
Flow Velocity Profile ◽  
The Stability ◽  
Special Case ◽  
Dimensional Wave

In this paper we examine the stability of a two-dimensional wake profile of the form u(y) = U∞(1 – r e-sy2) with respect to a pulsed disturbance at a point in the fluid. The disturbed flow forms an expanding wave packet which is convected downstream. Far downstream, where asymptotic expansions are valid, the motion at any point in the wave packet is described by a particular three-dimensional wave having complex wave-numbers. In the special case of very unstable flows, where viscosity does not have a significant influence, it is possible to evaluate the three-dimensional eigenvalues in terms of two-dimensional ones using the inviscid form of Squire's transformation. In this way each point in the physical plane can be linked to a particular two-dimensional wave growing in both space and time by simple algebraic expressions which are independent of the mean flow velocity profile. Computed eigenvalues for the wake profile are used in these relations to find the behaviour of the wave packet in the physical plane.

scholarly journals THE INFLUENCE OF BREAKER TYPE ON RIPRAP STABILITY

1970 ◽  
Vol 1 (12) ◽  
pp. 95 ◽  
Author(s):  
John P. Ahrens
Keyword(s):  
Test Data ◽  
Wave Action ◽  
Coastal Engineering ◽  
Research Center ◽  
Wave Tank ◽  
Engineering Research ◽  
The Stability ◽  
Type Intermediate

Test data related to the stability of dumped quarry stone riprap under wave action is presented The tests were conducted in the large 635-foot wave tank at the Coastal Engineering Research Center at near prototype scale The data indicate that the stability of the riprap is strongly influenced by the type of breaker The lowest riprap stability is associated with a breaker type intermediate between plunging and surging, sometimes referred to as a collapsing breaker.

scholarly journals Robustness of Polynomial Stability of Damped Wave Equations

2022 ◽  
Author(s):  
Dmytro Baidiuk ◽  
Lassi Paunonen
Keyword(s):  
Boundary Condition ◽  
Wave Equations ◽  
Sufficient Conditions ◽  
Two Dimensional ◽  
Polynomial Stability ◽  
One Dimensional ◽  
Acoustic Boundary Condition ◽  
The Stability ◽  
Perturbed Equation ◽  
Dimensional Wave

AbstractIn this paper we present new results on the preservation of polynomial stability of damped wave equations under addition of perturbing terms. We in particular introduce sufficient conditions for the stability of perturbed two-dimensional wave equations on rectangular domains, a one-dimensional weakly damped Webster’s equation, and a wave equation with an acoustic boundary condition. In the case of Webster’s equation, we use our results to compute explicit numerical bounds that guarantee the polynomial stability of the perturbed equation.

scholarly journals Method of the Laboratory Wave Generation for Two Dimensional Hydraulic Model Experiment in the Coastal Engineering Fields: Case of Random Waves

2021 ◽  
Vol 33 (6) ◽  
pp. 383-390
Author(s):  
Jong-In Lee ◽  
Il Rho Bae ◽  
Young-Taek Kim
Keyword(s):  
Wave Generation ◽  
Hydraulic Model ◽  
Coastal Engineering ◽  
Experimental Results ◽  
Random Wave ◽  
Two Dimensional ◽  
Random Waves ◽  
Coastal Structures ◽  
Successful Execution ◽  
The Stability

The experiments in coastal engineering are very complex and a lot of components should be concerned. The experience has an important role in the successful execution. Hydraulic model experiments have been improved with the development of the wave generator and the advanced measuring apparatus. The hydraulic experiments have the advantage, that is, the stability of coastal structures and the hydraulic characteristics could be observed more intuitively rather than the numerical modelings. However, different experimental results can be drawn depending on the model scale, facilities, apparatus, and experimenters. In this study, two-dimensional hydraulic experiments were performed to suggest the guide of the test wave(random wave) generation, which is the most basic and important factor for the model test. The techniques for generating the random waves with frequency energy spectrum and the range for the incident wave height [(HS)M/(HS)T = 1~1.05] were suggested. The proposed guide for the test wave generation will contribute to enhancing the reliability of the experimental results in coastal engineering.

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