scholarly journals WAVE OVERTOPPIMG EQUATION

1976 ◽  
Vol 1 (15) ◽  
pp. 156 ◽  
Author(s):  
J. Richard Weggel
Keyword(s):  
Scale Effects ◽  
Beach Erosion ◽  
Scale Model ◽  
Lake Okeechobee ◽  
Wave Runup ◽  
Large Wave ◽  
Engineering Research ◽  
Test Conditions ◽  
Model Wave ◽  
Wave Heights

In the early 1950's the Corps of Engineers' Jacksonville District initiated a series of laboratory tests to investigate the overtopping of proposed levee sections for Lake Okeechobee, Florida. For economic reasons, the alternative to build levees with crest elevations that were at times below the limit of wave runup was investigated and the quantities of water carried over the structures for various freeboard allowances, structure slopes and wave conditions determined. The initial tests were conducted at the Waterways Experiment Station (WES) in Vieksburg, Mississippi for the Jacksonville District at what was taken to be a 1 to 30 model scale. Model wave heights varied from 1+.05 cm to 12.2 cm (0.133 to 0.^0 ft). In order to expand the range of test conditions investigated, the Beach Erosion Board, currently the Coastal Engineering Research Center (CERC), commissioned an expanded series of tests that considered the overtopping of riprap faced, curved and stepped seawalls as well as the overtopping of "smooth" slopes. These tests, also conducted at WES, were considered to be at a 1 to 17 scale with model wave heights ranging from 5-36 cm to 21.5 cm (0.176 to O.706 ft). A number of tests were subsequently conducted in CERC's large wave tank to determine the influence scale effects might have on overtopping. These tests are referred to as 1 to 2 1/2 scale tests. The model wave heights investigated ranged from U8.8 cm to 11*0.2 cm. (1.60 to h.6o ft).

scholarly journals Focusing of long waves with finite crest over constant depth

2013 ◽  
Vol 469 (2153) ◽  
pp. 20130015 ◽  
Author(s):  
Utku Kânoğlu ◽  
Vasily V. Titov ◽  
Baran Aydın ◽  
Christopher Moore ◽  
Themistoklis S. Stefanakis ◽  
...  
Keyword(s):  
Source Region ◽  
Wave Theory ◽  
Long Waves ◽  
Constant Depth ◽  
Large Wave ◽  
Weakly Nonlinear ◽  
Scaling Relationships ◽  
2011 Japan Tsunami ◽  
Wave Heights ◽  
Run Up

Tsunamis are long waves that evolve substantially, through spatial and temporal spreading from their source region. Here, we introduce a new analytical solution to study the propagation of a finite strip source over constant depth using linear shallow-water wave theory. This solution is not only exact, but also general and allows the use of realistic initial waveforms such as N -waves. We show the existence of focusing points for N -wave-type initial displacements, i.e. points where unexpectedly large wave heights may be observed. We explain the effect of focusing from a strip source analytically, and explore it numerically. We observe focusing points using linear non-dispersive and linear dispersive theories, analytically; and nonlinear non-dispersive and weakly nonlinear weakly dispersive theories, numerically. We discuss geophysical implications of our solutions using the 17 July 1998 Papua New Guinea and the 17 July 2006 Java tsunamis as examples. Our results may also help to explain high run-up values observed during the 11 March 2011 Japan tsunami, which are otherwise not consistent with existing scaling relationships. We conclude that N -waves generated by tectonic displacements feature focusing points, which may significantly amplify run-up beyond what is often assumed from widely used scaling relationships.

scholarly journals ON THE IMPORTANCE OF CONSIDERING MULTIPLE SEASTATE REALIZATIONS WHEN ESTIMATING DESIGN LOADS IN MULTI-DIRECTIONAL SHALLOW-WATER WAVES

2020 ◽  
pp. 46
Author(s):  
Andrew Cornett ◽  
Scott Baker
Keyword(s):  
Shallow Water ◽  
Water Waves ◽  
Offshore Structures ◽  
Scale Model ◽  
Offshore Structure ◽  
Wave Condition ◽  
Directional Waves ◽  
Wave Heights ◽  
Design Loads ◽  
Peak Pressures

The objectives of this work are to close some of the knowledge gaps facing designers tasked with designing new offshore structures or upgrading older structures located in shallow waters and exposed to energetic multi-directional waves generated by passing hurricanes or cyclones. This will be accomplished by first investigating and characterizing the natural variability of the maximum wave heights and crest elevations found in multiple 2-hour long realizations of several short-crested shallow-water near-breaking seastates. Following this, the variability and repeatability of peak pressures and peak loads exerted on a 1/35 scale model of a gravity-based offshore structure are explored. The analysis focuses on establishing extreme value distributions for each realization, quantifying their variability, and exploring how the variability is diminished when results from multiple seastate realizations and repeated tests are combined. The importance of considering multiple realizations of a design wave condition when estimating peak values for use in design is investigated and highlighted.Recorded Presentation from the vICCE (YouTube Link): https://youtu.be/16bCsMd0OMc

scholarly journals Computational Analyses of the Effects of Wind Tunnel Ground Simulation and Blockage Ratio on the Aerodynamic Prediction of Flow over a Passenger Vehicle

Vehicles ◽  
2020 ◽  
Vol 2 (2) ◽  
pp. 318-341
Author(s):  
Chen Fu ◽  
Mesbah Uddin ◽  
Chunhui Zhang
Keyword(s):  
Wind Tunnel ◽  
Boundary Conditions ◽  
Physical Simulation ◽  
Cost Effective ◽  
Aerodynamic Characteristics ◽  
Operating Conditions ◽  
Scale Model ◽  
Blockage Ratio ◽  
Road Tunnel ◽  
Test Conditions

With the fast-paced growth of computational horsepower and its affordability, computational fluid dynamics (CFD) has been rapidly evolving as a popular and effective tool for aerodynamic design and analysis in the automotive industry. In the real world, a road vehicle is subject to varying wind and operating conditions that affect its aerodynamic characteristics, and are difficult to reproduce in a traditional wind tunnel. CFD has the potential of becoming a cost-effective way of achieving this, through the application of different boundary conditions. Additionally, one can view wind tunnel testing, be it a fixed-floor or rolling road tunnel, as a physical simulation of actual on-road driving. The use of on-road track testing, and static-floor, and rolling-road wind tunnel measurements are common practices in industry. Subsequently, we investigated the influences of these test conditions and the related boundary conditions on the predictions of the aerodynamic characteristics of the flow field around a vehicle using CFD. A detailed full-scale model of Hyundai Veloster with two vehicle configurations, one with the original and the other with an improved spoiler, were tested using a commercial CFD code STAR-CCM+ from Siemens. Both vehicle configurations were simulated using four different test conditions, providing overall eight different sets of simulation settings. The CFD methodology was validated with experimental data from the Hyundai Aero-acoustic Wind Tunnel (HAWT), by accurately reproducing the test section with static floor boundary conditions. In order to investigate the effect of the blockage ratio on the aerodynamic predictions, the vehicle models were then tested with moving ground plus rotating wheel boundary conditions, using a total of four virtual wind tunnel configurations, with tunnel solid blockage ratios ranging from 1.25%, which corresponds to the actual HAWT, to 0.04%, which presents an open air driving condition.

Centerwell Water Motions and Hydrodynamic Loading Using Viscous Flow Calculations

2008 ◽  
Author(s):  
Samuel Holmes ◽  
Joseph Gebara ◽  
Allan Magee
Keyword(s):  
Scale Effects ◽  
Vertical Motion ◽  
Scale Model ◽  
Navier Stokes ◽  
Open Area ◽  
Flow Models ◽  
Free Surface Waves ◽  
Natural Response ◽  
Termination Point

Most Spar platforms have a wet centerwell which provides a termination point for umbilicals and risers. The column of water in the centerwell is a dynamic system which can be excited by the wave action around the Spar as well as the platform’s own motions. When the exciting frequencies are close to the natural frequency of the water column, the vertical motion of the water in the centerwell can become large in large seastates. This might damage structures within the centerwell. A natural response to this problem is to restrict the fluid flow at the bottom of the centerwell by adding a plated structure to partially close the opening. The remaining open area in the centerwell determines the amount of damping as well as the loads on the plating which can be quite large in heavy seas. The problem addressed in this paper is the determination of the appropriate open area in the centerwell plate that will control the fluid vertical motion without requiring expensive reinforcements to the plating beyond the riser guide structure already present. Traditional design tools based on potential flow models appear to perform poorly for this problem because they do not model the viscous damping in the flow correctly. In this paper we use a Navier-Stokes solver to study the centerwell motions and centerwell plate loads for three centerwell plate geometries. It is found that the Spar motions and the free surface waves need to be included in these simulations. The centerwell water motions and centerwell plate loads are compared with those measured in a scale model experiment. Full-scale calculations are also carried out to determine the corresponding centerwell plate loads and centerwell water motions to assess scale effects.

Numerical Simulation of Nonlinear Wave Propagation and Breaking Over Constant-Slope Bottom

2006 ◽  
Author(s):  
Aggelos S. Dimakopoulos ◽  
Athanassios A. Dimas
Keyword(s):  
Numerical Simulation ◽  
Free Surface ◽  
Free Surface Flow ◽  
Surface Flow ◽  
Surface Boundary ◽  
Nonlinear Wave Propagation ◽  
Large Wave ◽  
Slope Bottom ◽  
Wave Heights ◽  
Constant Slope

The numerical simulation of the two-dimensional free-surface flow resulting from the propagation of nonlinear gravity waves over constant-slope bottom is presented. The simulation is based on the numerical solution of the Euler equations subject to the fully nonlinear free-surface boundary conditions and the appropriate bottom, inflow and outflow conditions using a hybrid finite-differences and spectral-method scheme. Wave breaking is accounted for by a surface roller model. The formulation includes a boundary-fitted transformation and is suitable for future extension to incorporate large-eddy and large-wave simulation terms. Results are presented for the simulation of the free-surface flow over two different bottom topographies, with constant slope values of 1:10 and 1:50, and three different inflow wave heights. Over the bottom slope, waves of small wave heights are modified according to linear theory. For nonlinear waves, wavelengths are becoming shorter, the free surface elevation deviates from its initial sinusoidal shape and wave heights increase with decreasing depth. Breaking is observed for the cases with the larger initial wave height and the smaller outflow depth.

LARGE SCALE EXPERIMENTS ON EVOLUTION AND RUN-UP OF BREAKING SOLITARY WAVES

2007 ◽  
Vol 01 (03) ◽  
pp. 257-272 ◽  
Author(s):  
KAO-SHU HWANG ◽  
YU-HSUAN CHANG ◽  
HWUNG-HWENG HWUNG ◽  
YI-SYUAN LI
Keyword(s):  
Solitary Wave ◽  
Wave Height ◽  
Solitary Waves ◽  
Water Depth ◽  
Large Scale ◽  
Scale Effects ◽  
Wave Heights ◽  
Run Up ◽  
Hydraulics Laboratory ◽  
The Waves

The evolution and run-up of breaking solitary waves on plane beaches are investigated in this paper. A series of large-scale experiments were conducted in the SUPER TANK of Tainan Hydraulics Laboratory with three plane beaches of slope 0.05, 0.025 and 0.017 (1:20, 1:40 and 1:60). Solitary waves of which relative wave heights, H/h0, ranged from 0.03 to 0.31 were generated by two types of wave-board displacement trajectory: the ramp-trajectory and the solitary-wave trajectory proposed by Goring (1979). Experimental results show that under the same relative wave height, the waveforms produced by the two generation procedures becomes noticeably different as the waves propagate prior to the breaking point. Meanwhile, under the same relative wave height, the larger the constant water depth is, the larger the dimensionless run-up heights would be. Scale effects associated with the breaking process are discussed.

Experiments on surface deformation arising from a subsurface fracture

1995 ◽  
Vol 32 (6) ◽  
pp. 1024-1034 ◽  
Author(s):  
Gang Wang ◽  
Maurice B. Dusseault ◽  
Jerzy T. Pindera
Keyword(s):  
Large Scale ◽  
Surface Deformation ◽  
Scale Effects ◽  
Model Simulation ◽  
Laboratory Data ◽  
Nonlinear Problems ◽  
Laboratory Simulation ◽  
Scale Model ◽  
Laboratory Model ◽  
Hydraulic Fractures

Laboratory model simulation of large-scale earth processes is rarely undertaken because of scale effects, nonlinearity, and questions of representativeness with respect to the real case. Hydraulic fractures generate distortion fields that can be measured with high precision both in the laboratory and in the field. A combination of field and laboratory data allows us to test our ability to measure displacements, make forward predictions, and invert real measurements; thus it is important to have some means of simulation, other than purely numerical simulation. This paper contains the results of a set of experiments on the surface deformation arising from a pressurized fracture, using laser holography and Fizeau interferometry of noncontacting techniques to precisely sample the displacement field above a scale model. The results are remarkably accurate and consistent, and compare reasonably well with analytical and numerical model predictions. The techniques have potential applications in geomechanics and geotechnical engineering for laboratory study of various linear and nonlinear problems. Key words : laboratory simulation, holographic, Fizeau interferometry, hydrofractures.

Hydrodynamic Performance of a Novel Free Surface Pitching Breakwater

2014 ◽  
Author(s):  
Vengatesan Venugopal ◽  
Stefan Zlatev
Keyword(s):  
Body Shape ◽  
Hydrodynamic Performance ◽  
Irregular Waves ◽  
Scale Model ◽  
Reflected Waves ◽  
Irregular Wave ◽  
Wave Flume ◽  
Floating Breakwater ◽  
Wave Heights ◽  
Transmission Ct

A new concept floating breakwater was developed and tested to evaluate its hydrodynamic performance in this paper. This innovative floating breakwater has a rocking body shape which could also be used as a wave power device. A scale model was tested in a wave flume under regular and irregular wave conditions for various combinations of wave frequencies and wave heights. The breakwater has been tested for three immersion depths of 0.05 m, 0.09 m and 0.13 m from still water level. The measured transmitted and reflected waves were used to evaluate the coefficients of transmission (CT), reflection (CR) and dissipation (CL). The results illustrated that the breakwater model performed at its best when submerged at 0.13m, as this immersion depth produced lower coefficients of transmission (CT), lower reflection coefficients (CR) and higher energy dissipation (CL) coefficients. The comparison between regular and irregular waves produced similar ranges of transmission, reflection and energy coefficients.

Ship Movements’ Analysis in a Physical Scale Model

2017 ◽  
Vol 372 ◽  
pp. 132-141
Author(s):  
Liliana Pinheiro ◽  
Joana Simão ◽  
João Alfredo Santos ◽  
Conceição Juana Fortes
Keyword(s):  
Physical Model ◽  
Fiber Optic ◽  
Transfer Functions ◽  
Model Tests ◽  
Scale Model ◽  
Physical Model Tests ◽  
Physical Scale ◽  
Wave Heights ◽  
Wave Conditions ◽  
The Waves

A set of physical model tests was run in to characterize the ship’s response to different wave conditions going from frequently-occurring conditions up to extreme ones. Several wave heights, periods and directions were generated. The waves around the ship were measured with probes and the movements of the ship were measured with a fiber-optic gyrocompass. Transfer functions are established and compared with numerical ones obtained with the WAMIT model.

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