Experimental Investigation of Tsunami Bore Forces on Vertical Walls

2013 ◽  
Vol 135 (2) ◽  
Author(s):  
I. N. Robertson ◽  
K. Paczkowski ◽  
H. R. Riggs ◽  
A. Mohamed
Keyword(s):  
Vertical Wall ◽  
State University ◽  
Flat Bottom ◽  
Large Wave ◽  
Wave Flume ◽  
Pressure Distributions ◽  
Vertical Walls ◽  
Series Of Experiments ◽  
Maximum Impact Force ◽  
Sloping Beach

A series of experiments have been carried out in the large wave flume (LWF) at Oregon State University to quantify tsunami bore forces on structures. These tests included “offshore” solitary waves, with heights up to 1.3 m, that traveled over a flat bottom, up a sloping beach, and breaking onto a flat reef. Standing water depths on the reef varied from 0.05 m to 0.3 m. Resulting bores on the reef measured up to approximately 0.8 m. After propagating along the reef, the bores struck a vertical wall. The resulting forces and pressures on the wall were measured. The test setup in the LWF is described, and the experimental results are reported. The results include forces and pressure distributions. Results show that the bores propagated with a Froude number of approximately 2 and that the forces follow Froude scaling. Finally, a design formula for the maximum impact force is given. The formula is shown to be an improvement over existing formulas found in the literature.

Tsunami Bore Forces on Walls

2011 ◽  
Author(s):  
I. N. Robertson ◽  
K. Paczkowski ◽  
H. R. Riggs ◽  
A. Mohamed
Keyword(s):  
Phase Ii ◽  
Phase 1 ◽  
Vertical Wall ◽  
Lateral Loads ◽  
Flat Bottom ◽  
Large Wave ◽  
Wave Flume ◽  
Pressure Distributions ◽  
Wave Basin ◽  
Maximum Impact Force

A series of experiments have been carried out at Oregon State University to quantify tsunami bore forces on structures. Phase 1 of the tests was carried out in the Tsunami Wave Basin (TWB), while Phase II of the tests were carried out in the Large Wave Flume (LWF) at approximately twice the scale of the Phase I tests. These latter tests included ‘offshore’ solitary waves, with heights up to 1.3 m, that traveled over a flat bottom, up a sloping beach and breaking onto a flat ‘fringing reef’. Standing water depths on the reef varied from 0.05 m to 0.3 m. Resulting bores on the reef measured up to approximately 0.8 m. After propagating along the reef, the bores struck a vertical wall. The resulting forces and pressures on the wall were measured. The test setup for the Phase II tests in the LWF is described and the experimental results are reported. The results include forces and pressure distributions. Results show that the bores propagated with a Froude number of approximately 2, and that the forces follow Froude scaling. Finally, a design formula for the maximum impact force is given. The formula is shown to be an improvement over existing formulas found in the literature. The lateral forces are shown to be quite significant compared to traditional lateral loads on vertical wall elements.

Reynolds Averaged Navier-Stokes Computational Solution for Experimentally Generated High Velocity Bore Impact on Vertical Walls

2014 ◽  
Author(s):  
K. W. Paczkowski ◽  
H. R. Riggs ◽  
I. N. Robertson ◽  
M. H. Kobayashi
Keyword(s):  
High Velocity ◽  
Vertical Wall ◽  
Experimental Tests ◽  
Navier Stokes ◽  
Computational Domain ◽  
Flat Bottom ◽  
Large Wave ◽  
Wave Flume ◽  
Constant Height ◽  
Wave Research

A set of computational model tests was carried out to simulate high velocity bore impact on a vertical wall. The results were compared to a series of experimental tests conducted at the O.H. Hinsdale Wave Research Laboratory, large wave flume (LWF) at Oregon State University (OSU) [1]. Experimental tests included scaled tsunami experimental bores that traveled over a flat bottom [2]. The experimental bores were generated by solitary waves propagating over a sloping beach and breaking onto a flat reef [3]. After traveling through the reef portion, the generated bore impacted a vertical wall. In the experiments the resulting forces and pressures on the wall were measured. The aim of the study was to computationally regenerate the experimental bore flow and its impact on the vertical wall. Two computational domain setups were tested: 1) a dam break [3–8,10–16] and 2) a new approach, in which constant height and velocity water inflow was defined at the inlet to the domain. The two numerical approaches were compared to the LWF experimental data [3].

Nonlinear and Dissipative Characteristics of a Combined Random-Cnoidal Wave Field

2017 ◽  
Author(s):  
James M. Kaihatu ◽  
John T. Goertz ◽  
Samira Ardani ◽  
Alex Sheremet
Keyword(s):  
Wave Spectrum ◽  
Leading Edge ◽  
Dissipation Function ◽  
Indian Ocean Tsunami ◽  
Random Wave ◽  
Cnoidal Wave ◽  
State University ◽  
Large Wave ◽  
Wave Flume ◽  
Wave Trains

Images of the 2004 Indian Ocean tsunami at landfall shows a leading edge marked by short waves (“fission” waves). These waves appear to be cnoidal in shape and of a temporal and spatial scale in line with the longest swell present in the region, and may interact with the longer waves in the background random wave spectrum. As part of a comprehensive series of experiments, the Large Wave Flume at Oregon State University (USA) was used to generate and measure the properties of cnoidal, random, and combined cnoidal-random wave trains. Both the nonlinear energy transfer characteristics (via bispectral analysis) and dissipation characteristics (via a proxy dissipation function) are studied for all generated wave conditions. It is generally determined that the characteristics of the cnoidal wave dominate the combined cnoidal-random wave signals if the energy of the cnoidal wave is at least equal to that of the random wave.

The Fission Process of N-Waves Over a Mild Slope

2008 ◽  
Vol 24 (2) ◽  
pp. 205-214
Author(s):  
Y.-H. Lin ◽  
H.-H. Hwung
Keyword(s):  
Flow Field ◽  
Nonlinear Case ◽  
Fission Process ◽  
Breaking Effect ◽  
Wave Flume ◽  
The Third ◽  
Near Shore ◽  
Series Of Experiments ◽  
Hydraulics Laboratory ◽  
Sloping Beach

ABSTRACTThe aim of this paper is to investigate the mechanism of the fission process and the flow field of N-waves in the near-shore region. From the elaborate experimental analysis, a subsequence of a second soliton released during shoaling reigon is identified to realize the further evolution of N-waves over a sloping beach, in comparison with the non-fission case. The fission index is indicated by a dimensionless factor A0/d0, which is used to describe the nonlinearity as well. It is known that the reflecting wave and the breaking effect could easily initiate another soliton, especially for strong nonlinear case. A series of experiments were conducted in a super wave flume (300m × 5m × 5.2m) at Tainan Hydraulics Laboratory (THL), National Cheng Kung University (NCKU). The entire evolution of the leading and second solitons and the generation mechanism for the third soliton would be discussed in this paper.

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.

Experimental and Analytical Study of Water-Driven Debris Impact Forces on Structures1

2014 ◽  
Vol 136 (4) ◽  
Author(s):  
H. R. Riggs ◽  
D. T. Cox ◽  
C. J. Naito ◽  
M. H. Kobayashi ◽  
P. Piran Aghl ◽  
...  
Keyword(s):  
Full Scale ◽  
State University ◽  
Large Wave ◽  
Substantial Impact ◽  
Wave Flume ◽  
Shipping Container ◽  
Lehigh University ◽  
Impact Forces ◽  
Utility Pole ◽  
The Impact

Water-driven debris generated during tsunamis and hurricanes can impose substantial impact forces on structures that are often not designed for such loads. This paper presents the design and results of an experimental and analytical program to quantify these potential impact forces. Two types of prototypical debris are considered: a wood log and a shipping container. Full-scale impact tests at Lehigh University (LU) were carried out with a wooden utility pole and a shipping container. The tests were carried out in-air. The purpose of these tests was to provide baseline, full-scale results. Because of size limitations, a 1:5 scale shipping container model was used for in-water tests in the Oregon State University (OSU) large wave flume. These tests were used to quantify the effect of the fluid on the impact forces. Results from both experimental programs are presented and compared with analytical predictions. The predictions are found to be in sufficient agreement such that they can be used for design. A fundamental finding is that the impact forces are dominated by the structural impact, with a secondary effect provided by the fluid. Both forces are quantified in the paper.

scholarly journals FULL SCALE IMPACT TESTS OF AN OVERTOPPING BORE ON A VERTICAL WALL IN THE LARGE WAVE FLUME (GWK) IN HANNOVER

2012 ◽  
Vol 1 (33) ◽  
pp. 62 ◽  
Author(s):  
Julien De Rouck ◽  
Koen Van Doorslaer ◽  
Tom Versluys ◽  
Karunya Ramachandran ◽  
Stefan Schimmels ◽  
...  
Keyword(s):  
Return Period ◽  
Structural Design ◽  
Vertical Wall ◽  
Full Scale ◽  
Impact Loads ◽  
Flow Depth ◽  
Large Wave ◽  
Wave Flume ◽  
Hydraulic Process ◽  
The Impact

To meet up with the requirements of the Flemish Government, the Belgian coastline needs a protection to a storm with a return period of 1000 years. At well-chosen locations, storm walls will be built, and for the structural design of these walls the impact loadings need to be known. Tests have been carried out at full scale in the Grosser Wellen Kanal, to determine the impact loads by overtopping bores. Wave overtopping over the crest of the dike occurs, and the overtopping bore progresses along the horizontal crest of the dike before impacting the storm wall. It is of major importance that such a wall can withstand the impacts. This paper describes the hydraulic process on the crest of the dike, expressed with parameters such as flow depth and flow velocity, and links them to the impact measured on the storm wall. Both pressures and forces are measured, and compared to each other.

Water-Driven Debris Impact Forces on Structures: Experimental and Theoretical Program

2013 ◽  
Author(s):  
H. R. Riggs ◽  
D. T. Cox ◽  
C. J. Naito ◽  
M. H. Kobayashi ◽  
P. Piran Aghl ◽  
...  
Keyword(s):  
Full Scale ◽  
State University ◽  
Large Wave ◽  
Substantial Impact ◽  
Wave Flume ◽  
Shipping Container ◽  
Lehigh University ◽  
Impact Forces ◽  
Theoretical Predictions ◽  
The Impact

Water-driven debris generated during tsunamis and hurricanes can impose substantial impact forces on structures that are often not designed for such loads. This paper presents the design and results of an experimental and theoretical program to quantify these potential impact forces. Two types of prototypical debris are considered: a wood log and a shipping container. Full-scale impact tests at Lehigh University were carried out with a wooden utility pole and a shipping container. The tests were carried out in-air, and were designed to provide baseline, full-scale results. A 1:5 scale shipping container model was used for in-water tests in the Oregon State University large wave flume. These tests were used to quantify the effect of the fluid on the impact forces. Results from both experimental programs are presented and compared with theoretical predictions. The analytical predictions are found to be in sufficient agreement such that they can be used for design. A fundamental takeaway is that the impact forces are dominated by the structural impact, with a secondary affect provided by the fluid. Both forces are quantified in the paper.

scholarly journals Microelectrode Velocity Effects and Aquatic Eddy Covariance Measurements under Waves

2016 ◽  
Vol 33 (2) ◽  
pp. 263-282 ◽  
Author(s):  
Clare E. Reimers ◽  
H. Tuba Özkan-Haller ◽  
Andrea T. Albright ◽  
Peter Berg
Keyword(s):  
Eddy Covariance ◽  
Irregular Waves ◽  
Velocity Measurements ◽  
Large Wave ◽  
Wave Flume ◽  
Eddy Covariance Measurements ◽  
Average Flux ◽  
Series Of Experiments ◽  
Wave Induced ◽  
Oxygen Measurements

AbstractInterest in validating the eddy covariance (EC) technique under wave-induced flows led to a series of experiments in a 104-m-long large wave flume (LWF) using an acoustic Doppler velocimeter (ADV) and two oxygen microelectrodes (tips ~2 mm apart) mounted on a sturdy tripod. Four additional ADVs positioned within the flume provided comparative near-bed velocity measurements during experiments with irregular waves over a sand bed. These measurements revealed that modifications of local turbulence by the tripod frame were insignificant. However, errors in velocity measurements were at times observed for setups where the microelectrode tips protruded into the ADV’s measurement volume. Disparate oxygen microelectrode velocity effects (stirring sensitivities) combined with response time offsets were also identified as problems, adding biases to EC flux derivations. Microelectrode velocity effects were further investigated through modeling designed to mimic the LWF data, and through examination of a 12-h dataset from the Oregon shelf. The modeling showed that under progressive waves, an artificial EC flux, or bias, arises most severely when the velocity sensitivity of the microelectrode is unequal in opposing flow directions or augmented by horizontal currents, and the velocity and oxygen data are not perfectly aligned in time. Sensitivities to wave motions were seen in the oxygen measurements from the Oregon shelf, contributing to an average flux of +2.7 ± 0.6 mmol m−2 day−1 (SE, n = 22) at wave frequencies. Since overall EC fluxes equaled only −4.1 ± 1.8 mmol m−2 day−1 (SE, n = 22), sources of EC biasing coupled to waves cannot be ruled out as potential problems for estimating exact benthic oxygen fluxes under common continental shelf field conditions.

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.

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