scholarly journals FULL-SCALE WAVE ATTACK OF UNIFORMLY SLOPING SEA DYKES

1988 ◽  
Vol 1 (21) ◽  
pp. 161 ◽  
Author(s):  
Alfred Fuhrboter ◽  
Uwe Sparboom
Keyword(s):  
Concrete Block ◽  
Breaking Waves ◽  
Shock Pressure ◽  
Full Scale ◽  
Federal Republic Of Germany ◽  
Large Wave ◽  
Wave Channel ◽  
Initial Block ◽  
New Research ◽  
Geotextile Filter

Shock pressure phenomena due to breaking waves acting on sloping faces of sea dykes are focussed in this paper. The probability approach is pointed out and maximum shock pressure estimations are given for smooth and impermeable dyke slopes 1:4 and 1:6. An extension of the results to steeper and flatter slopes is proposed. Results of full-scale stability tests on concrete block slope revetments are also reported in this paper. For various structural solutions with granular and geotextile filter layers stability numbers are recommended. Initial block lifting is explained physically by pressure measurements. The full-scale experiments were carried out in the new research facility LARGE WAVE CHANNEL of the universities in Hannover and Braunschweig (Federal Republic of Germany).

scholarly journals WAVE TESTS OF REVETMENT USING MACHINE-PRODUCED INTERLOCKING BLOCKS

1966 ◽  
Vol 1 (10) ◽  
pp. 59
Author(s):  
Jay V. Hall
Keyword(s):  
Low Cost ◽  
Concrete Block ◽  
Breaking Waves ◽  
Vertical Movement ◽  
Light Weight ◽  
Shore Protection ◽  
Individual Property ◽  
Large Wave ◽  
Engineering Research ◽  
The Individual

Continued demand for relatively low-cost shore protection, in bays, estuaries, and comparable bodies of water has resulted in accelerated investigation in this area. Further, there is a great demand for a system that can be constructed by the individual property owner without recourse to a contractor or special construction equipment. Work along these lines gained impetus through the successful installation of a light-weight concrete-block revetment in 1962. This paper reports on the further development of light-weight block revetments through tests in the Large Wave Tank at Coastal Engineering Research Center (CERC). Two types of blocks were tested on a 1 on 2 slope, one a machine-produced tongue-and-groove type weighing 75 pounds, and the other a hand-produced shiplap type weighing 150 pounds, the latter having twice the surface area of the former. In all, ten tests were made with wave heights ranging from 1.5 to 6.2 feet and wave periods ranging from 3.0 to 6.0 seconds. During the tests observations were made regarding the displacement of blocks and the vertical movement of the face of the slope when attacked by waves. Data derived from the tests have provided information which has resulted in the development of a machine-produced block which remained stable under the continuous attack of 4.7-second 4.8-foot breaking waves. Comparative tests showed that the machine-produced tongue-and-groove blocks have greater stability than the hand-produced shiplap type.

THE INFLUENCE OF CENTRE BOW LENGTH ON SLAMMING LOADS AND MOTIONS OF LARGE WAVE-PIERCING CATAMARANS

2021 ◽  
Vol 160 (A1) ◽  
Author(s):  
J R Shahraki ◽  
G A Thomas ◽  
M R Davis
Keyword(s):  
Wave Height ◽  
Full Scale ◽  
Bending Moments ◽  
Regular Waves ◽  
Large Wave ◽  
Towing Tank ◽  
Segmented Model ◽  
Model Experiments ◽  
Slamming Load ◽  
Wave Induced

The effect of various centre bow lengths on the motions and wave-induced slamming loads on wave-piercing catamarans is investigated. A 2.5 m hydroelastic segmented model was tested with three different centre bow lengths and towed in regular waves in a towing tank. Measurements were made of the model motions, slam loads and vertical bending moments in the model demi-hulls. The model experiments were carried out for a test condition equivalent to a wave height of 2.68 m and a speed of 20 knots at full scale. Bow accelerations and vertical bending moments due to slamming showed significant changes with the change in centre bow, the longest centre bow having the highest wave-induced loads and accelerations. The increased volume of displaced water which is constrained beneath the bow archways is identified as the reason for this increase in the slamming load. In contrast it was found that the length of centre bow has a relatively small effect on the heave and pitch motions in slamming conditions.

scholarly journals WAVE RUN-UP OBSERVATIONS ON REVETMENTS WITH DIFFERENT POROSITIES

2012 ◽  
Vol 1 (33) ◽  
pp. 73 ◽  
Author(s):  
Stefan Schimmels ◽  
Michalis Vousdoukas ◽  
Dagmara Wziatek ◽  
Katharina Becker ◽  
Fabian Gier ◽  
...  
Keyword(s):  
Data Analysis ◽  
Concrete Block ◽  
Video Data ◽  
Coastal Protection ◽  
Large Wave ◽  
Wave Flume ◽  
New Type ◽  
Run Up ◽  
Highly Porous ◽  
Good Agreement

Wave run-up plays an important role in the design of coastal protection structures. However, none of the existing formulae for wave run-up predictions explicitly considers the effect of revetment porosity. Recently, two revetments have been tested in the Large Wave Flume (GWK) of Forschungszentrum Küste (FZK), a new type of highly porous polyurethane bonded (PBA revetment) revetment and a smooth interlocked pattern placed concrete block revetment (IPPB revetment), which is considered as “weakly permeable” for the present study. Wave run-up is evaluated by video data analysis based on timestack image processing. The results derived from the timestacks are compared to run-up data measured with conventional wire gauges and the good agreement demonstrates the accuracy and reliability of the video data analysis. The effect of the porosity of the revetment is incorporated into the EuroTop wave run-up formula, showing that for the present case it may reduce the relative run-up heights Ru,2%/Hm0 by about 25 % to 50 % as compared to a smooth impermeable slope.

scholarly journals THE ECONOMIC VALUE OP A NEW BREAKWATER ARMOUR UNIT 'DOLOS'

1966 ◽  
Vol 1 (10) ◽  
pp. 50 ◽  
Author(s):  
E.M. Merrifield ◽  
J.A. Zwamborn
Keyword(s):  
Economic Value ◽  
Full Scale ◽  
Field Conditions ◽  
Test Results ◽  
Shore Protection ◽  
Wave Channel ◽  
New Type ◽  
Rubble Mound ◽  
The Stability ◽  
Made In

The Dolos, a new type of armour unit which closely resembles a normal ship's anchor, was developed and tried out under field conditions on the main breakwater of East London harbour. Since these full-scale Dolosse proved very successful, tests were made in a wave channel to compare the stability of Dolosse with other known types of armour blocks. The test results showed that the Dolos is outstandingly stable, and since manufacture and random placing of Dolosse offers no particular difficulties it is concluded that in many cases the use of Dolosse in armour layers may lead to more economical solutions for rubble mound breakwater and shore protection works.

scholarly journals RUNUP RECIPE FOR PERIODIC WAVES ON UNIFORMLY SLOPING BEACHES

1966 ◽  
Vol 1 (10) ◽  
pp. 21 ◽  
Author(s):  
Wm. G. Van Dorn
Keyword(s):  
Small Amplitude ◽  
Breaking Waves ◽  
Wave Crest ◽  
Periodic Waves ◽  
Conservation Of Energy ◽  
Wave Channel ◽  
Wave Trains ◽  
Elevation Measurement ◽  
Steep Slopes ◽  
Modified Theory

The shoaling enhancement of small-amplitude, dispersive wave trains traveling over uniform, impermeable slopes was observed in a specially-constructed wave channel, where the reproducible wave elevation measurement accuracy was about .0005-in. These observations substantially support the enhancement predicted from linear theory (conservation of energy flux) except in very shallow water and on very steep slopes, where accelerative effects become important. On the hypothesis that small-amplitude runup theory might be similarly valid for periodic waves of finite height, provided that the positive incident wave amplitude Is replaced by the local crest height above still water, this theory was modified to include the effect of the superelevation under a wave crest due to profile asymmetry. The modified theory is shown to agree acceptably with runup observations of larger waves previously reported - both for breaking and non-breaking waves. Because solutions to the modified theory cannot conveniently be obtained by manual calculation, a nomograph chart is included, from which runup predictions can be easily made, given only the wave height, period, and water depth a wavelength or so from shore, and the beach slope.

scholarly journals Numerical Modeling of Failure Mechanisms in Articulated Concrete Block Mattress as a Sustainable Coastal Protection Structure

2021 ◽  
Vol 13 (22) ◽  
pp. 12794
Author(s):  
Ramin Safari Ghaleh ◽  
Omid Aminoroayaie Yamini ◽  
S. Hooman Mousavi ◽  
Mohammad Reza Kavianpour
Keyword(s):  
Numerical Modeling ◽  
Concrete Block ◽  
Breaking Waves ◽  
Physical Models ◽  
Coastal Protection ◽  
Similarity Parameter ◽  
Environmental Friendliness ◽  
Shoreline Protection ◽  
Concrete Blocks ◽  
Run Up

Shoreline protection remains a global priority. Typically, coastal areas are protected by armoring them with hard, non-native, and non-sustainable materials such as limestone. To increase the execution speed and environmental friendliness and reduce the weight of individual concrete blocks and reinforcements, concrete blocks can be designed and implemented as Articulated Concrete Block Mattress (ACB Mat). These structures act as an integral part and can be used as a revetment on the breakwater body or shoreline protection. Physical models are one of the key tools for estimating and investigating the phenomena in coastal structures. However, it does have limitations and obstacles; consequently, in this study, numerical modeling of waves on these structures has been utilized to simulate wave propagation on the breakwater, via Flow-3D software with VOF. Among the factors affecting the instability of ACB Mat are breaking waves as well as the shaking of the revetment and the displacement of the armor due to the uplift force resulting from the failure. The most important purpose of the present study is to investigate the ability of numerical Flow-3D model to simulate hydrodynamic parameters in coastal revetment. The run-up values of the waves on the concrete block armoring will multiply with increasing break parameter (0.5<ξm−1,0<3.3) due to the existence of plunging waves until it (Ru2%Hm0=1.6) reaches maximum. Hence, by increasing the breaker parameter and changing breaking waves (ξm−1,0>3.3) type to collapsing waves/surging waves, the trend of relative wave run-up changes on concrete block revetment increases gradually. By increasing the breaker index (surf similarity parameter) in the case of plunging waves (0.5<ξm−1,0<3.3), the low values on the relative wave run-down are greatly reduced. Additionally, in the transition region, the change of breaking waves from plunging waves to collapsing/surging (3.3<ξm−1,0<5.0), the relative run-down process occurs with less intensity.

Shock Pressure of Breaking Waves (I)

1966 ◽  
Vol 9 (1) ◽  
pp. 83-96 ◽  
Author(s):  
Hisashi Mitsuyasu
Keyword(s):  
Breaking Waves ◽  
Shock Pressure

PECULIARITIES OF THE SAND PARTICLES SUSPENDING UNDER INFLUENCE OF THE REGULAR WAVES

2018 ◽  
Author(s):  
М. Крыленко ◽  
M. Krylenko ◽  
Й. Грюне ◽  
Y. Gryune ◽  
Р. Косьян ◽  
...  
Keyword(s):  
Laboratory Experiment ◽  
Suspended Sediment ◽  
Suspended Sediment Concentration ◽  
Sediment Concentration ◽  
Time Interval ◽  
Regular Waves ◽  
Large Wave ◽  
Wave Channel ◽  
Sand Particles ◽  
Using Data

In the presented paper some peculiarities of suspending and distribution of sand particles under influence of the regular waves in time interval less than the wave period are discussed using data from laboratory experiment “Hannover 2008”. The experiment was carried out in the Large Wave Channel (GWK). The presented data show that fluctuations of suspended sediment concentration are very largely initiated by individual waves.

The Influences of Centre Bow Length on Slamming Loads and Motions of Large Wave-Piercing Catamarans

2018 ◽  
Vol Vol 160 (A1) ◽  
Author(s):  
J R Shahraki ◽  
G A Thomas ◽  
M R Davis
Keyword(s):  
Wave Height ◽  
Full Scale ◽  
Bending Moments ◽  
Regular Waves ◽  
Large Wave ◽  
Towing Tank ◽  
Segmented Model ◽  
Model Experiments ◽  
Slamming Load ◽  
Wave Induced

The effect of various centre bow lengths on the motions and wave-induced slamming loads on wave-piercing catamarans is investigated. A 2.5 m hydroelastic segmented model was tested with three different centre bow lengths and towed in regular waves in a towing tank. Measurements were made of the model motions, slam loads and vertical bending moments in the model demi-hulls. The model experiments were carried out for a test condition equivalent to a wave height of 2.68 m and a speed of 20 knots at full scale. Bow accelerations and vertical bending moments due to slamming showed significant changes with the change in centre bow, the longest centre bow having the highest wave-induced loads and accelerations. The increased volume of displaced water which is constrained beneath the bow archways is identified as the reason for this increase in the slamming load. In contrast it was found that the length of centre bow has a relatively small effect on the heave and pitch motions in slamming conditions.

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