scholarly journals WAVE RUN-UP AT SEA DIKES UNDER OBLIQUE WAVE APPROACH

1982 ◽  
Vol 1 (18) ◽  
pp. 50
Author(s):  
E. Tautenhain ◽  
S. Kohlhase ◽  
H.W. Partenscky
Keyword(s):  
Irregular Waves ◽  
Wave Direction ◽  
Wave Runup ◽  
Natural Conditions ◽  
Wave Impact ◽  
Oblique Wave ◽  
Wave Flume ◽  
Wave Approach ◽  
Impact Forces ◽  
Run Up

Besides wave impact forces, erosion of the inner side of a sea dike is a serious cause of destruction. Therefore, wave run-up and overtopping effects have to be considered with respect to the safety of a dike. Strong relations were found between both these influences (TAUTENHAIN et.al., 1980, 1981, 1982), based on experiments in a wave flume and using an energy conservation concept. However, under natural conditions, an oblique wave approach has to be considered. This paper deals with the influence of wave direction on wave runup on a smooth dike slope in order to provide a basis for calculating the overtopping rates for both regular and irregular waves.

Non-Linear Wave Runup Along the Side of Ships Causing Green Water Problems: Experiments and First CFD Calculations

2014 ◽  
Author(s):  
Bas Buchner ◽  
Joris van den Berg ◽  
Joop Helder ◽  
Tim Bunnik
Keyword(s):  
Irregular Waves ◽  
Green Water ◽  
Linear Wave ◽  
Wave Direction ◽  
Wave Runup ◽  
Complex Processes ◽  
Non Linear ◽  
Run Up ◽  
Spilling Breakers ◽  
Water Problems

Large relative wave motions along the side of a ship can lead to green water on the deck. With a simplified test setup of a thin plate under an angle with the wave direction (to separate non-linear wave run up from motion effects), the non-linear wave reflection along the side of ships is studied in the present paper. These pilot tests with regular and irregular waves gave new insight in the process of non-linear wave run up with plunging and spilling breakers close to the plate. The complex processes observed made clear that linear or second order models will not be able to predict this behavior accurately. Previously [1] it was concluded that CFD methods that allow wave breaking are necessary for a prediction of these important effects. In the present paper a first pilot study is presented with an improved Volume of Fluid (VoF) Method. It is concluded that the method is in principle able to present these relative wave motions, but that a finer gridding is necessary to study the detailed flows.

scholarly journals REFLECTION OF IRREGULAR WAVES AT PARTIALLY REFLECTING STRUCTURES INCLUDING OBLIQUE WAVE APPROACH

1986 ◽  
Vol 1 (20) ◽  
pp. 162 ◽  
Author(s):  
Hans-Joachim Scheffer ◽  
Soren Kohlhase
Keyword(s):  
Reflection Coefficient ◽  
Three Dimensional ◽  
Diffraction Theory ◽  
Wave Pattern ◽  
Irregular Waves ◽  
Breaking Wave ◽  
Oblique Wave ◽  
Wave Flume ◽  
Wave Approach ◽  
Wave Basin

The reflection of irregular seas is increasingly considered in coastal engineering and harbour design as well with respect to wave pattern at the structure and energy dissipation as regarding the dimensioning of structures exposed to waves. It becomes evident that the three-dimensional sea state (oblique wave approach, irregularity of the waves) at partially-reflecting structures of a complex design cannot be described by means of a constant reflection coefficient alone, as is common practice. This is due to the fact that the coefficient is largely frequency-dependent and the physically effective reflection point of the structure cannot be clearly specified. In the light of this, basic investigations on wave reflection have been performed with different partially-reflecting structures, wave spectra and wave approach angles. In addition to laboratory experiments using both a wave flume and a wave basin, a theoretical solution based on diffraction theory was determined to describe the wave field in the reflection area of various structures. The investigations were restricted to non-breaking wave conditions. The reflection behaviour of structures is expressed by a complex reflection coefficient, containing two parameters, which have to be determined by model tests.

Wave Run-Up at Sea Dikes under Oblique Wave Approach

1982 ◽  
Author(s):  
E. Tautenhain ◽  
S. Kohlhase ◽  
H. W. Partenscky
Keyword(s):  
Oblique Wave ◽  
Wave Approach ◽  
Run Up ◽  
Sea Dikes

scholarly journals Nonlinear run-ups of regular waves on sloping structures

2012 ◽  
Vol 12 (12) ◽  
pp. 3811-3820 ◽  
Author(s):  
T.-W. Hsu ◽  
S.-J. Liang ◽  
B.-D. Young ◽  
S.-H. Ou
Keyword(s):  
Boussinesq Equations ◽  
Irregular Waves ◽  
Coastal Structures ◽  
Regular Waves ◽  
Wave Flume ◽  
Coastal Risk ◽  
Run Up ◽  
Two Parameters ◽  
Prediction Capability ◽  
Good Agreement

Abstract. For coastal risk mapping, it is extremely important to accurately predict wave run-ups since they influence overtopping calculations; however, nonlinear run-ups of regular waves on sloping structures are still not accurately modeled. We report the development of a high-order numerical model for regular waves based on the second-order nonlinear Boussinesq equations (BEs) derived by Wei et al. (1995). We calculated 160 cases of wave run-ups of nonlinear regular waves over various slope structures. Laboratory experiments were conducted in a wave flume for regular waves propagating over three plane slopes: tan α =1/5, 1/4, and 1/3. The numerical results, laboratory observations, as well as previous datasets were in good agreement. We have also proposed an empirical formula of the relative run-up in terms of two parameters: the Iribarren number ξ and sloping structures tan α. The prediction capability of the proposed formula was tested using previous data covering the range ξ ≤ 3 and 1/5 ≤ tan α ≤ 1/2 and found to be acceptable. Our study serves as a stepping stone to investigate run-up predictions for irregular waves and more complex geometries of coastal structures.

A Vertical Axis Wave Turbine With Cup Blades

2015 ◽  
Author(s):  
Yingchen Yang ◽  
Isaiah Diaz ◽  
Misael Morales ◽  
Pablo Obregon
Keyword(s):  
Vertical Axis ◽  
Ocean Waves ◽  
Irregular Waves ◽  
Wave Direction ◽  
Experimental Conditions ◽  
Water Motion ◽  
Wave Flume ◽  
Simple Waves ◽  
Alignment Angle ◽  
Local Water

A new wave energy converter (WEC) design and some test results are discussed in this work. Among a variety of WEC technologies being explored to date, a huge majority employs wave-driven reciprocating motion (e.g., heave, pitch, sway, reciprocating bending or curving, etc.) to harness energy. It is well known that reciprocating WECs only work well at or near a predefined wave frequency, in a preferred alignment angle with the wave direction (except for the heave type), and in organized waves. But real ocean waves are chaotic and have daily changing frequencies and propagation directions. To circumvent those issues of the reciprocating WECs, a new unidirectional WEC concept — a vertical axis wave turbine — is explored in this research. The key component of the wave turbine is a rotor, which has a number of uniquely arranged hemispherical shells as blades. When the rotor is exposed in waves with its shaft vertically oriented, local water motion in any spatial directions (due to waves) can always drive the rotor for unidirectional rotation regardless of the wave type and propagation direction. In other words, the rotor can rely on omnidirectional water motion to realize its unidirectional rotation. A model wave turbine employing this rotor design has been tested in a wave flume. Upon a successful demonstration in simulated irregular waves, the rotor’s unidirectional performance was systematically characterized under various experimental conditions in simple waves.

Physical and Numerical Investigations on Wave Run-Up and Dissipation under Breakwater with Fence Revetment

2021 ◽  
Vol 9 (12) ◽  
pp. 1355
Author(s):  
Enjin Zhao ◽  
Lin Mu ◽  
Zhaoyang Hu ◽  
Xinqiang Wang ◽  
Junkai Sun ◽  
...  
Keyword(s):  
Wave Height ◽  
Water Depth ◽  
Significant Wave Height ◽  
Irregular Waves ◽  
Structure Stability ◽  
Wave Impact ◽  
Significant Wave ◽  
Tide Level ◽  
Run Up ◽  
The Impact

Revetment elements and protective facilities on a breakwater can effectively weaken the impact of waves. In order to resist storm surges, there is a plan to build a breakwater on the northern shore of Meizhou Bay in Putian City, China. To better design it, considering different environmental conditions, physical and numerical experiments were carried out to accurately study the effects of the breakwater and its auxiliary structures on wave propagation. In the experiments, the influence of the wave type, initial water depth, and the structure of the fence plate are considered. The wave run-up and dissipation, the wave overtopping volume, and the structure stability are analyzed. The results indicate that the breakwater can effectively resist the wave impact, reduce the wave run-up and overtopping, and protect the rear buildings. In addition, under the same still water depth and significant wave height, the amount of overtopped water under regular waves is larger than that under irregular waves. With the increase of the still water depth and significant wave height, the overtopped water increases, which means that when the storm surge occurs, damage on the breakwater under the high tide level is greater than that under the low tide level. Besides, the fence plate can effectively dissipate energy and reduce the overtopping volume by generating eddy current in the cavity. Considering the stability and the energy dissipation capacity of the fence plate, it is suggested that a gap ratio of 50% is reasonable.

scholarly journals NUMERICAL STUDY OF WAVE RUN-UP AT PERMEABLE FIXED REVETMENT SLOPE

2017 ◽  
pp. 32
Author(s):  
Izmail Kantarzhi ◽  
Sergii Kivva ◽  
Natalia V Shunko
Keyword(s):  
Porous Medium ◽  
Numerical Model ◽  
Large Scale ◽  
Numerical Study ◽  
Water Filtration ◽  
Wave Surface ◽  
Natural Conditions ◽  
Wave Flume ◽  
Run Up ◽  
Large Scale Tests

The numerical model of wave surface elevation and water filtration in the saturated-unsaturated porous medium is developed. The model uses to define the parameters of the wave run-up at the slope protected by the permeable fixed layer. The model shows the wave surface in the different times, including the wave run-up height at the slope and wave run-down. Also, the velocities in the upper protected layer as well in the soil body of the slope are defined. Model is verified with using of the published large-scale tests with the slopes protected by Elastocoast technology layers. The tests were carried out in the wave flume of Technical University Braunschweig. The numerical model may be applied to calculate the maximal waves run-up at the protected engineering and beach slopes in natural conditions.

Probability Distributions for Wave Runup on Offshore Platform Columns

2009 ◽  
Author(s):  
Amir H. Izadparast ◽  
John M. Niedzwecki
Keyword(s):  
Probability Distribution ◽  
Weibull Distribution ◽  
Empirical Model ◽  
Offshore Structures ◽  
Distribution Model ◽  
Wave Runup ◽  
Wave Impact ◽  
Quadratic Transformation ◽  
L Moments ◽  
Run Up

For the design of offshore structures it is important to accurately predict wave runup and thus avoid topside inundation and minimize the wave impact on the underside of the deck structure. In this paper a three-parameter probability distribution function for nonlinear wave run-up amplitudes is presented. It builds upon previous studies and utilizes the quadratic transformation of incident waves. The parameters of this probability distribution are estimated from the data using method of L-moments and the explicit relation between the parameters and L-moments is presented. The L-moments themselves are linear combinations of ordered data and consequently they are less influenced by outliers and unexpectedly large values. Earlier theoretical models, based on simplified diffraction theory, are presented and compared with the L-moments model. A three-parameter Weibull distribution model that utilizes the method of L-moments is derived and discussed. Run-up measurements from a mini-TLP model test program are used as the basis for comparison of the three methods. This study demonstrates that the new empirical model and Weibull distribution are more robust in representing the probability distribution of nonlinear runup amplitudes especially for the weakly nonlinear cases with moderate steepness. Although the new empirical model and Weibull distribution have different probability structure their estimates are found to be fairly close.

scholarly journals Nonlinear Simulation of Wave Train Impact on a Vertical Seawall

Water ◽  
2018 ◽  
Vol 10 (8) ◽  
pp. 986 ◽  
Author(s):  
Dezhi Ning ◽  
Xiang Li ◽  
Chongwei Zhang
Keyword(s):  
Free Surface ◽  
Wave Train ◽  
Wave Load ◽  
Wave Impact ◽  
Nonlinear Simulation ◽  
Irregular Wave ◽  
Numerical Wave Flume ◽  
Wave Flume ◽  
Free Surface Oscillations ◽  
Run Up

A 2D nonlinear numerical wave flume is developed to investigate the wave train impact on a vertical seawall. Fully nonlinear kinematic and dynamic boundary conditions are satisfied on the instantaneous free surface. Cases of single-, double- and multi-crest wave trains are discussed. For single-crest wave train cases, the present nonlinear results are compared with the solution of the Serre-Green-Naghdi (SGN) model, showing good agreement. For double-crest wave train cases, the SGN model underestimates the maximum wave run-up along the vertical seawall. Compared with the linear results, the nonlinearity for double-crest cases can lead to an evident increase of the wave run-up and high-frequency free-surface oscillations. Through a fast Fourier analysis, evident nonlinear characteristics of the time series of the wave run-up and wave load during the wave impact process are confirmed. For multi-crest wave train cases, irregular wave run-ups can be observed. In some cases, the wave run-up along the vertical seawall can reach about 6 times that of the incident wave, which should be considered carefully in a practical design.

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