scholarly journals SCALE EFFECTS IN RUBBLE-MOUND BREAKWATERS

1972 ◽  
Vol 1 (13) ◽  
pp. 102
Author(s):  
Kenneth W. Wilson ◽  
Ralph H. Cross
Keyword(s):  
Boundary Layer ◽  
Scale Effects ◽  
Layer Growth ◽  
Effective Porosity ◽  
Model Tests ◽  
Experimental Results ◽  
Linear Wave ◽  
Reflection And Transmission ◽  
Rubble Mound ◽  
Rubble Mound Breakwaters

In conducting model tests of wave transmission through permeable rubble-mound breakwaters, it is impossible to satisfy simultaneously the Froude and Reynolds criteria for dynamic similarity. The common practice has been to scale the wave parameters and breakwater dimensions in accordance with the Froude Number, and to use large models. This study represents an attempt to develop theoretical expressions for the coefficients of reflection and transmission as functions of the effective porosity of the breakwater structure, as influenced by the Reynolds-dependent boundary layer growth an the pores. These expressions use linear wave theory and boundary layer theory to estimate the effective decrease in pore diameter due to growth of the displacement boundary layer thickness in the pore. The theoretical expressions were compared with experimental results from a series of three model tests with breakwaters having vertical faces and using gravel with diameters of 1.37 in., 0.762 in., and 0.324 in. respectively. The prototype to model ratios (using the largest model as the prototype) were 1/1.80 and 1/4.23 respectively. The experimental results show clearly the existence of scale effects in both coefficients of reflection and transmission. The theoretical expressions were found to overestimate the scale effect in reflection and to underestimate it in transmission.

scholarly journals CEOHYDRAULIC INVESTIGATIONS OF RUBBLE MOUND BREAKWATERS

1988 ◽  
Vol 1 (21) ◽  
pp. 166 ◽  
Author(s):  
W. Burger ◽  
H. Oumeraci ◽  
H.W. Partenscky
Keyword(s):  
Pore Pressure ◽  
Scale Effects ◽  
Numerical Models ◽  
Model Tests ◽  
Physical Models ◽  
Core Material ◽  
Scale Model ◽  
Small Scale ◽  
Rubble Mound ◽  
Rubble Mound Breakwaters

Due to the increase of ship sizes in recent decades a number of harbours and terminals have been built in deeper waters. Accordingly, the structures which have to provide protection against wave action become higher, too. In most cases, these protective structures are of the rubble mound type. Under such conditions the flow induced by waves within the breakwater and the related geotechnical behaviour of the rubble mound fill become more significant fcr the overall stability and should be considered in the design. In addition, it is known that the scales usually adopted in hydraulic models (1:30 to 1:60) for investigating the stability of large rubble mound breakwaters generally lead to scale effects with respect to the flow field inside the breakwater. This means that small-scale model tests are not appropriate for investigating the internal flow patterns or for evaluating the pore pressure field induced by the incident waves in,the core material. because of the uncontrolled conditions in the prototype, and since the actual permeability of the prototype rubble mound fill cannot be predicted (segregation, settlement, variation in grading, etc.), the use of large-scale physical models seems to be the most promising method for basic investigations of this kind. Moreover, the results of such largescale model tests may be used to validate the usual smaller scale models and to calibrate numerical models. Therefore, it is one of the objectives of our research programme on rubble mound breakwaters, which started in 1987, to concentrate on the evaluation of the wave-induced flow and pore pressure distribution within the breakwater.

scholarly journals STABILITY OF HIGH DENSITY CUBES IN RUBBLE MOUND BREAKWATERS

2020 ◽  
pp. 4
Author(s):  
Yalcin Yuksel ◽  
Marcel van Gent ◽  
Esin Cevik ◽  
H. Alper Kaya ◽  
Irem Gumuscu ◽  
...  
Keyword(s):  
Relative Density ◽  
Slope Angle ◽  
High Density ◽  
Experimental Results ◽  
Normal Density ◽  
Stability Number ◽  
Damage Initiation ◽  
Rubble Mound ◽  
The Stability ◽  
Rubble Mound Breakwaters

The stability number for rubble mound breakwaters is a function of several parameters and depends on unit shape, placing method, slope angle, relative density, etc. In this study two different densities for cubes in breakwater armour layers were tested to determine the influence of the density on the stability. The experimental results show that the stability of high density blocks were found to be more stable and the damage initiation for high density blocks started at higher stability numbers compared to normal density cubes.

scholarly journals Correction: Eldrup, M.R., et al. Stability of Rubble Mound Breakwaters—A Study of the Notional Permeability Factor, based on Physical Model Tests. Water 2019, 11, 934

Water ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 2483
Author(s):  
Mads Røge Eldrup ◽  
Thomas Lykke Andersen ◽  
Hans Falk Burcharth
Keyword(s):  
Physical Model ◽  
Model Tests ◽  
Permeability Factor ◽  
Physical Model Tests ◽  
Rubble Mound ◽  
Rubble Mound Breakwaters

The authors wish to make the following corrections to this paper [...]

scholarly journals TOE BERM DESIGN FOR RUBBLE-MOUND BREAKWATERS: EXAMPLE OF THE SAFI POWER PLANT PROJECT

2017 ◽  
pp. 34
Author(s):  
COUTOSTHEVENOT Marie ◽  
HONG Kyung-Wook
Keyword(s):  
Power Plant ◽  
Physical Model ◽  
Design Feature ◽  
Breaking Waves ◽  
Model Tests ◽  
Construction Methods ◽  
Physical Model Tests ◽  
Rubble Mound ◽  
Hydraulics Laboratory ◽  
Rubble Mound Breakwaters

DAEWOO E&C (Engineering & Construction) is in charge constructing a new 1320 MW coal-fired power plant located approximately 15 km south-west of the city of Safi in Morocco. ARTELIA Eau & Environnement was appointed by the Contractor to perform the hydraulic design review of the rubble-mound breakwaters protecting the intake and outfall. The toe berm is a key design feature of rubble-mound breakwaters built in breaking conditions, since it helps to support the armour layer and protect the structure from potential scour-induced damage. The initial toe berm design was based on Van Der Meer’s empirical formula (1998). Due to the very shallow water conditions, the toe design was verified through physical model tests (2D and 3D) in ARTELIA’s hydraulics laboratory located in Pont-de-Claix, near Grenoble (France). The physical model tests demonstrated that the toe berm (6t rocks, 3:1 slope) was not stable at key singular locations, namely roundheads and roots, where direct impacts of breaking waves caused severe damage. Given the site conditions and the construction methods, the usual solutions consisting in increasing the rock size and/or placing the toe berm in a trench had to be ruled out. It was hence decided to reinforce the toe with artificial blocks and to use rectangular concrete blocks with holes. These blocks reduced the anti-stabilizing pressure difference between the top and bottom of the blocks (Tanimoto et al., 1996) and drag force due to the considerable current. They are more usually used at the toe of vertical caissons.

SCALE EFFECTS IN RUBBLE MOUND BREAKWATERS CONSIDERING WAVE ENERGY BALANCE

2007 ◽  
Author(s):  
Damiano Scarcella ◽  
M. Izaskun Benedicto ◽  
Antonio Moñino ◽  
Miguel A. Losada
Keyword(s):  
Energy Balance ◽  
Wave Energy ◽  
Scale Effects ◽  
Rubble Mound ◽  
Rubble Mound Breakwaters

scholarly journals WAVE OVERTOPPING ON RUBBLE MOUND BREAKWATERS

1988 ◽  
Vol 1 (21) ◽  
pp. 57 ◽  
Author(s):  
Pierliugi Aminti ◽  
Leopoldo Franco
Keyword(s):  
Hydraulic Model ◽  
Model Tests ◽  
Geometric Parameters ◽  
Random Wave ◽  
Wave Overtopping ◽  
Wave Flume ◽  
Rubble Mound ◽  
Rubble Mound Breakwaters

The paper gives the results of an extensive series of hydraulic model tests carried out in a random wave flume, in order to study the effects on wave overtopping of the main geometric parameters of a typical rubble mound breakwater with crown wall. The results have been compared with those from other studies and analyzed with different methods. Generalized design diagrams and formulae for the prediction of overtopping discharges are finally given for a large number of popular breakwater configurations.

Artificial Intelligence and Rubble-Mound Breakwater Stability

2012 ◽  
pp. 1499-1506
Author(s):  
Gregorio Iglesias Rodriguez ◽  
Alberte Castro Ponte ◽  
Rodrigo Carballo Sanchez ◽  
Miguel Ángel Losada Rodriguez
Keyword(s):  
Physical Model ◽  
Model Tests ◽  
Wave Action ◽  
Ann Model ◽  
Climate Conditions ◽  
Wave Flume ◽  
Physical Model Tests ◽  
Rubble Mound ◽  
The Stability ◽  
Rubble Mound Breakwaters

Breakwaters are coastal structures constructed to shelter a harbour basin from waves. There are two main types: rubble-mound breakwaters, consisting of various layers of stones or concrete pieces of different sizes (weights), making up a porous mound; and vertical breakwaters, impermeable and monolythic, habitually composed of concrete caissons. This article deals with rubble-mound breakwaters. A typical rubble-mound breakwater consists of an armour layer, a filter layer and a core. For the breakwater to be stable, the armour layer units (stones or concrete pieces) must not be removed by wave action. Stability is basically achieved by weight. Certain types of concrete pieces are capable of achieving a high degree of interlocking, which contributes to stability by impeding the removal of a single unit. The forces that an armour unit must withstand under wave action depend on the hydrodynamics on the breakwater slope, which are extremely complex due to wave breaking and the porous nature of the structure. A detailed description of the flow has not been achieved until now, and it is unclear whether it will be in the future in view of the turbulent phenomena involved. Therefore the instantaneous force exerted on an armour unit is not, at least for the time being, amenable to determination by means of a numerical model of the flow. For this reason, empirical formulations are used in rubble-mound design, calibrated on the basis of laboratory tests of model structures. However, these formulations cannot take into account all the aspects affecting the stability, mainly because the inherent complexity of the problem does not lend itself to a simple treatment. Consequently the empirical formulations are used as a predesign tool, and physical model tests in a wave flume of the particular design in question under the pertinent sea climate conditions are de rigueur, except for minor structures. The physical model tests naturally integrate all the complexity of the problem. Their drawback lies in that they are expensive and time consuming. In this article, Artificial Neural Networks are trained and tested with the results of stability tests carried out on a model breakwater. They are shown to reproduce very closely the behaviour of the physical model in the wave flume. Thus an ANN model, if trained and tested with sufficient data, may be used in lieu of the physical model tests. A virtual laboratory of this kind will save time and money with respect to the conventional procedure.

Prototype measurements and small-scale model tests of wave overtopping at shallow rubble-mound breakwaters: the Ostia-Rome yacht harbour case

2009 ◽  
Vol 56 (2) ◽  
pp. 154-165 ◽  
Author(s):  
Leopoldo Franco ◽  
Jimmy Geeraerts ◽  
Riccardo Briganti ◽  
Marc Willems ◽  
Giorgio Bellotti ◽  
...  
Keyword(s):  
Model Tests ◽  
Scale Model ◽  
Small Scale ◽  
Wave Overtopping ◽  
Rubble Mound ◽  
Rubble Mound Breakwaters ◽  
Small Scale Model
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