scholarly journals WAVE LOADS ON EXPOSED JETTIES: DESCRIPTION OF LARGE SCALE EXPERIMENTS AND PRELIMINARY RESULTS

2011 ◽  
Vol 1 (32) ◽  
pp. 18 ◽  
Author(s):  
Luca Martinelli ◽  
Alberto Lamberti ◽  
Maria Gabriella Gaeta ◽  
Matteo Tirindelli ◽  
John Alderson ◽  
...  
Keyword(s):  
Large Scale ◽  
Research Team ◽  
Scale Effects ◽  
Wave Loads ◽  
Large Wave ◽  
Preliminary Results ◽  
Wave Flume ◽  
Air Content ◽  
Wave Induced ◽  
The Impact

The large scale experiments described in this paper were carried out at the Large Wave Flume (GWK, Große Wellenkanal) in Hanover (Germany). The research team included Universities of Bologna (IT), Edinburgh (UK), Southampton (UK), Plymouth (UK), HR Wallingford (UK) and Coast & Harbor Engineering Inc (USA). Wave-induced loads on close-to-prototype scale jetties were measured, with particular attention to scale effects due to air content in water. The aim of the paper is to present the tests, describe the impact process and give preliminary results concerning uplift loads.

Small and Large Scale Experimental Investigations of Wave Loads on a Slender Pile Within Closely Spaced Neighbouring Piles

2014 ◽  
Author(s):  
Lisham Bonakdar ◽  
Hocine Oumeraci
Keyword(s):  
Laboratory Tests ◽  
Large Scale ◽  
Model Tests ◽  
Scale Model ◽  
Research Centre ◽  
Experimental Investigations ◽  
Small Scale ◽  
Wave Loads ◽  
Large Wave ◽  
Wave Flume

Wave loads on a slender pile within a group of piles are studied by means of (i) large-scale laboratory tests carried out in the Large Wave Flume (GWK) of the Coastal Research Centre (FZK) in Hannover, and (ii) small scale experiments performed in 2 m-wide wave flume of Leichtweiss-Institute for Hydraulic Engineering and Water Resources (LWI), in Braunschweig, Germany. The small scale model tests (LWI) were scaled down (1:6.5) by Froude law from the large scale model tests (GWK). Scale and model effects are examined by comparing the results of small and large scale laboratory tests.

scholarly journals BREAKING WAVE KINEMATICS, LOCAL PRESSURES, AND FORCES ON A TRIPOD STRUCTURE

2012 ◽  
Vol 1 (33) ◽  
pp. 71 ◽  
Author(s):  
Arndt Hildebrandt ◽  
Torsten Schlurmann
Keyword(s):  
Wave Front ◽  
Wave Breaking ◽  
Large Scale ◽  
Three Dimensional ◽  
Model Tests ◽  
Scale Model ◽  
Breaking Wave ◽  
Wave Loads ◽  
Large Wave ◽  
The Impact

This paper presents breaking wave loads on a tripod structure from physical model tests and numerical simulations. The large scale model tests (1:12) are described as well as the validation of the three dimensional numerical model by comparison of CFD wave gauge data and pressures with measurements in the large wave flume inside and outside the impact area. Subsequently, the impact areas due to a broken wave, a curled wave front as well as for wave breaking directly at the structure with a partly vertical wave front are compared to each other. Line forces in terms of slamming coefficients with variation in time and space are derived from CFD results and the velocity distribution is presented at the onset of wave breaking. Finally, the results are briefly discussed in comparison to other slamming studies.

scholarly journals BONDED POROUS REVETMENTS – EFFECT OF POROSITY ON WAVE-INDUCED LOADS AND HYDRAULIC PERFORMANCE

2012 ◽  
Vol 1 (33) ◽  
pp. 45 ◽  
Author(s):  
Sven Liebisch ◽  
Juan Carlos Alcérreca Huerta ◽  
Andreas Kortenhaus ◽  
Hocine Oumeraci
Keyword(s):  
Large Scale ◽  
Hydraulic Performance ◽  
Primary Objective ◽  
Scale Model ◽  
Large Wave ◽  
Wave Flume ◽  
Wide Range ◽  
First Results ◽  
The Stability ◽  
Wave Induced

The porosity and roughness of bonded revetments are both crucial for the hydraulic performance and the wave loading of the revetment and its foundation, and thus for the stability and durability of the entire structure. This is briefly shown by the selected results of a tentative comparative analysis of two large-scale test series performed in the Large Wave Flume (GWK) Hanover with two significantly different revetments: a highly porous and rough polyurethane bonded aggregate (PBA) revetment and an almost impermeable and relatively smooth interlocked pattern placed block (IPPB) revetment. These results motivated the initiation of the three years research project BoPoRe (Bonded Porous Revetments) which has the primary objective to investigate more systematically and separately the relative importance of both porosity and roughness for different slope steepnesses. This project is briefly introduced and the first results of preliminary scale model tests using 9 configurations for the porosity and roughness of the revetment subject to a wide range of wave conditions (surf similarity parameters 0.93-7.21) are briefly discussed.

scholarly journals WAVE LOADS ON AND BENEATH BONDED PERMEABLE REVETMENTS

2011 ◽  
Vol 1 (32) ◽  
pp. 17
Author(s):  
Gisa Ludwigs ◽  
Hocine Oumeraci ◽  
Tijl Staal
Keyword(s):  
Large Scale ◽  
Water Structure ◽  
Scale Model ◽  
Research Centre ◽  
Wave Loads ◽  
Large Wave ◽  
Wave Flume ◽  
Large Scale Model ◽  
Wide Range ◽  
Coastal Research

Permeable revetments made of bonded mineral aggregates may increasingly be favoured compared to standard revetments. However, the physical processes associated with the water–structure–soil-interaction for a wide range of wave conditions are still not well understood. Therefore, systematic large-scale model tests have been performed in the Large Wave Flume (GWK) of the Coastal Research Centre (FZK) in Hannover, with the intention of improving the understanding of these processes.

scholarly journals Large-Scale Laboratory Experiments on Mussel Dropper Lines in Ocean Surface Waves

2020 ◽  
Vol 9 (1) ◽  
pp. 29
Author(s):  
Rebekka Gieschen ◽  
Christian Schwartpaul ◽  
Jannis Landmann ◽  
Lukas Fröhling ◽  
Arndt Hildebrandt ◽  
...  
Keyword(s):  
Large Scale ◽  
Laboratory Experiments ◽  
Blue Mussel ◽  
Farming Systems ◽  
Quality Parameter ◽  
Large Wave ◽  
Marine Aquaculture ◽  
Ocean Surface Waves ◽  
Wave Flume ◽  
Waves And Currents

The rapid growth of marine aquaculture around the world accentuates issues of sustainability and environmental impacts of large-scale farming systems. One potential mitigation strategy is to relocate to more energetic offshore locations. However, research regarding the forces which waves and currents impose on aquaculture structures in such conditions is still scarce. The present study aimed at extending the knowledge related to live blue mussels (Mytilus edulis), cultivated on dropper lines, by unique, large-scale laboratory experiments in the Large Wave Flume of the Coastal Research Center in Hannover, Germany. Nine-months-old live dropper lines and a surrogate of 2.0 m length each are exposed to regular waves with wave heights between 0.2 and 1.0 m and periods between 1.5 and 8.0 s. Force time histories are recorded to investigate the inertia and drag characteristics of live mussel and surrogate dropper lines. The surrogate dropper line was developed from 3D scans of blue mussel dropper lines, using the surface descriptor Abbott–Firestone Curve as quality parameter. Pull-off tests of individual mussels are conducted that reveal maximum attachment strength ranges of 0.48 to 10.55 N for mussels that had medium 3.04 cm length, 1.60 cm height and 1.25 cm width. Mean drag coefficients of CD = 3.9 were found for live blue mussel lines and CD = 3.4 for the surrogate model, for conditions of Keulegan–Carpenter number (KC) 10 to 380, using regular wave tests.

scholarly journals Improvement of Drift Calculation in Mothy Operational Oil Spill Prediction System

2003 ◽  
Vol 2003 (1) ◽  
pp. 1067-1072 ◽  
Author(s):  
Pierre Daniel ◽  
Fabien Marty ◽  
Patrick Josse ◽  
Chafih Skandrani ◽  
Rachid Benshila
Keyword(s):  
Oil Spill ◽  
Large Scale ◽  
Stokes Drift ◽  
Vertical Shear ◽  
Transport Modelling ◽  
Meteorological Model ◽  
Drift Model ◽  
Linear Waves ◽  
Wave Induced ◽  
The Impact

ABSTRACT MOTHY (Modèle Océanique de Transport d'Hydrocarbures) is a pollutant drift model, developed and operated by Météo-France. MOTHY includes hydrodynamic coastal ocean modelling and real time atmospheric forcing from a global meteorological model. Pollutants can be oil or floating objects. To improve forecasts on the Mediterranean Sea, several methods were tested to inject large scale currents (permanent part) into the MOTHY system. The best results were obtained with monthly means of currents at 5 meters (from Mercator system). The addition of altimetric corrections improved the results. In addition the impact of wave (or swell) current, which is usually neglected in such models, is investigated. The literature has surprisingly little to say on the topic of wave-driven surface oil slicks. Earlier review on oil spill transport modelling includes wave driven transport among potential advection mechanisms. The discussion of wave-induced advection (mass transport) adopts a Lagrangian framework, focusing on the analyses of Stokes and Longuet-Higgins for the vertical profile of the Lagrangian velocity beneath waves. In our work, the action of a vertical shear due to waves is accounted for by including the Stokes drift due to weakly non linear waves. We evaluate this term and compare with observations of Erika pollution incident.

scholarly journals BREAKING AND WASH UP OF SOLITARY WAVES ON A COMPOSITE BEACH

2020 ◽  
pp. 29
Author(s):  
Hajo von Hafen ◽  
Jacob Stolle ◽  
Nils Goseberg ◽  
Ioan Nistor
Keyword(s):  
Solitary Waves ◽  
Horizontal Plane ◽  
Large Scale ◽  
Propagation Path ◽  
Rock Falls ◽  
Damage Potential ◽  
Large Wave ◽  
Beach Slope ◽  
Wave Flume ◽  
Run Up

Hazardous events, such as landslides, rock slides, rock falls or avalanches often generate extreme, impulsive waves when entering water bodies (Fuchs & Hager, 2015). These waves are approximated by solitary waves and researchers investigate their damage potential when inundating built environment. Deepening the understanding of solitary waves running up a uniform beach slope and propagating over a subsequent horizontal plane can help to reduce and mitigate damage and the number of casualties caused by such a hazardous event. So far, few authors addressed this specific setting near-shore (Fuchs & Hager, 2015; Zelt & Raichlen, 1991). In this study, large scale solitary waves propagate about 200 m in in the Large-Wave Flume (GWK, 307 m 5 m 7 m) at the Coastal Research Center in Hannover, Germany then they run up a beach slope and subsequently break, generating a bore which advances onto a subsequent, initially dry, horizontal surface. Unlike previous studies, the generated solitary waves broke close to the edge between the beach slope and the horizontal plane section. The overall aim of this study is to investigate the characteristics of the broken waves' dynamics. In addition, their surge profile and front celerity are compared to those of the non-breaking solitary waves. Subsequently, the differences between the velocity regimes along the bore propagation path are presented and linked to the fundamental physical processes behind.

scholarly journals LOADING OF VERTICAL WALLS BY OVERTOPPING BORES USING PRESSURE AND FORCE SENSORS - A LARGE SCALE MODEL STUDY

2012 ◽  
Vol 1 (33) ◽  
pp. 44 ◽  
Author(s):  
Karunya Ramachandran ◽  
Rebeca Roldan Genzalez ◽  
Hocine Oumeraci ◽  
Stefan Schimmels ◽  
Matthias Kudella ◽  
...  
Keyword(s):  
Large Scale ◽  
Vertical Wall ◽  
Pressure Sensors ◽  
Scale Model ◽  
Force Sensors ◽  
Research Project ◽  
Joint Research ◽  
Large Wave ◽  
Wave Flume ◽  
Joint Research Project

This study is based on the data obtained from tests carried out in the Large Wave Flume (Grosser Wellenkanal (GWK)) in Hannover in the frame of a joint research project of Ghent University (Belgium) and Forschungszentrum Küste (FZK, Germany). The goal of the research project is to determine the wave induced loads on vertical storm walls located at the end of overtopped dike, which are designed to protect coastal cities from overtopping and floods. The loads resulting from waves overtopping the dike and impacting the vertical wall as a bore are measured by means of both force and pressure sensors. This paper describes the results of pressure and force records at the vertical wall, including a comparative analysis of the overall forces obtained by pressure integration and force sensors for two different wall setups: Fully blocked wall and partially blocked wall.

Observations of wave attenuation, scour, and subsurface pore pressures acrossbthree marsh restoration sill structures on a sandy bed

Shore & Beach ◽  
2020 ◽  
pp. 14-30
Author(s):  
Jordan Converse ◽  
Meagan Wengrove ◽  
Pedro Lomonaco
Keyword(s):  
Sediment Transport ◽  
Large Scale ◽  
Wave Attenuation ◽  
Oyster Shell ◽  
Water Levels ◽  
Structure Stability ◽  
Large Wave ◽  
Sea Levels ◽  
Wave Flume ◽  
Living Shoreline

With rising sea levels and more frequent exposure to extreme storms, coastlines worldwide are vulnerable to increased erosion and loss of natural marsh lands. In an effort to lessen these impacts, there is a growing practice of adapting hard or “gray” coastline protection techniques to more nature-based features that promote habitat and ecosystem health. Living shoreline marsh restorations utilize natural and naturebased materials to protect marsh shores from erosion while also allowing intertidal flushing to promote the health and diversity of the marsh. Our study investigates three types of living shoreline sill designs exposed to average and storm-energy wave conditions at varying water levels. The sills were designed to mimic constructed sills in practice (rock, oyster shell, tree root wads), but more generally vary in structure porosity and material dissipation potential. Large-scale laboratory experiments were conducted in the large wave flume at the O.H. Hinsdale Wave Research Laboratory. Wave transmission and reflection are used to demonstrate wave attenuation capability of each sill structure. Scour of the sill, bedload sediment transport rates on the seaward and shoreward sides of the sill, and sediment pore-water vertical hydraulic gradients were used to demonstrate the potential for sediment transport and liquefaction. Results will contribute to understanding the effect of sill material porosity and mass on structure stability, and the effectiveness of using green living shoreline sill structures in the continued effort to establish design criteria for living shoreline implementation.

scholarly journals MEASUREMENTS OF THE STEADY CURRENTS OUTSIDE THE SURF ZONE

2011 ◽  
Vol 1 (32) ◽  
pp. 49 ◽  
Author(s):  
Pietro Scandura ◽  
Erminia Capodicasa ◽  
Enrico Foti
Keyword(s):  
Surf Zone ◽  
Scale Effects ◽  
Velocity Profiles ◽  
Sea Waves ◽  
Mean Velocity ◽  
Large Wave ◽  
Wave Flume ◽  
Wave Trough ◽  
Steady Current ◽  
The Mean

The results of an experimental study concerning with the measurements of the steady current induced by sea waves approaching the coast are reported. The experiments have been performed in a large wave flume in order to minimize the scale effects. The measurements have been carried out at four different stations along the wave flume by using Acoustic Doppler Velocimeters. The results show that the mean velocity profiles are significantly influenced by the wave period. In particular, when the period reduces the mean velocity gradient close to the wave trough increases. The trend of the velocity profiles is different from that predicted by the theory and mostly reported by other experiments. However, experimental results are reported in literature which are in a qualitative agreement with the present ones.

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