scholarly journals WAVE HEIGHT DISTRIBUTION IN CONSTANT AND FINITE DEPTHS

2012 ◽  
Vol 1 (33) ◽  
pp. 15 ◽  
Author(s):  
Sofia Caires ◽  
Marcel R.A. Van Gent
Keyword(s):  
Shallow Water ◽  
Wave Height ◽  
Wave Breaking ◽  
Rayleigh Distribution ◽  
Height Distribution ◽  
High Wave ◽  
Wave Height Distribution ◽  
Individual Wave ◽  
Wave Heights

Several alternatives to the Rayleigh distribution have been proposed for describing individual wave heights in regions where depth-induced wave breaking occurs. The most widely used of these is the so-called Battjes and Groenendijk distribution. This distribution has been derived and validated in a context of a shallow water foreshore waves propagating over a gently sloping shallow region towards the shore. Its validity for waves propagating in regions with shallow flat bottoms is investigated here. It is concluded that the distribution on average underestimates (outside its range of validity) high wave height measurements in shallow flat bottoms by as much as 15%.

Dependence of Shape Parameter of Weibull Distribution on Wave Spectral Width and Nonlinearity

2008 ◽  
Author(s):  
Changliang Li ◽  
Bingchen Liang ◽  
Lin Zhao
Keyword(s):  
Weibull Distribution ◽  
Wave Height ◽  
Shape Parameter ◽  
Wave Train ◽  
Spectral Width ◽  
Rayleigh Distribution ◽  
Height Distribution ◽  
Irregular Wave ◽  
Wave Height Distribution ◽  
Ocean Environment

In practice, the wave height distribution associated with an irregular wave train is always mathematically modeled as a Rayleigh distribution. However, the realistic ocean wave height distribution might deviate from a Rayleigh distribution. The present study demonstrates that a better mathematical model for wave height distribution under realistic ocean environment is a Weibull distribution. In comparison with a Rayleigh distribution, a Weibull distribution has the flexibility on choosing its “shape parameter”. According to the nonlinear Monte Carlo simulations, this study investigates the nonlinearity and spectral width effects on the shape parameter for the Weibull wave height distribution. A new empirical formula for calculating the shape parameter is proposed, which can be used easily in application.

Wave height distribution in shallow water

1985 ◽  
Vol 12 (4) ◽  
pp. 309-319 ◽  
Author(s):  
T.S. Shahul Hameed ◽  
M. Baba
Keyword(s):  
Shallow Water ◽  
Wave Height ◽  
Height Distribution ◽  
Wave Height Distribution

Wave Distributions and Sampling Variability

2007 ◽  
Author(s):  
O̸istein Hagen
Keyword(s):  
Wave Height ◽  
Extreme Values ◽  
Height Distribution ◽  
Short Term ◽  
Sea State ◽  
Sampling Variability ◽  
Wave Statistics ◽  
Individual Wave ◽  
Wave Heights ◽  
Crest Height

The paper describes the effect of sampling variability on the predicted extreme individual wave height and the predicted extreme individual crests height for long return periods, such as for the 100-year maximum wave height and 100-year maximum crest height. We show that the effect of sampling variability is different for individual crest or wave height as compared to for significant wave height. The short term wave statistics is modeled by the Forristall crest height distribution and the Forristall wave height distribution [3,4]. Samples from the 3-hour Weibull distribution are simulated for 100.000 years period, and the 100-year extreme values for wave heights and crest heights determined for respectively 20 minute and 3 hour sea states. The simulations are compared to results obtained by probabilistic analysis. The paper shows that state of the art analysis approaches using the Forristall distributions give about unbiased estimates for extreme individual crest or wave height if implemented appropriately. Direct application of the Forristall distributions for 3-hour sea state parameters give long term extremes that are biased low, and it is shown how the short term distributions can be modified such that consistent results for 20 minute and 3 hour sea states are obtained. These modified distributions are expected applicable for predictions based on hindcast sea state statistics and for the environmental contour approach.

Wave Height Distribution in Mixed Sea States

2001 ◽  
Vol 124 (1) ◽  
pp. 34-40 ◽  
Author(s):  
German Rodriguez ◽  
C. Guedes Soares ◽  
Mercedes Pacheco ◽  
E. Pe´rez-Martell
Keyword(s):  
Wave Height ◽  
Probabilistic Models ◽  
Simulated Data ◽  
Peak Frequency ◽  
Frequency Separation ◽  
Height Distribution ◽  
Zero Crossing ◽  
Frequency Wave ◽  
Wave Height Distribution ◽  
Wave Heights

The statistical distribution of zero-crossing wave heights in Gaussian mixed sea states is examined by analyzing numerically simulated data. Nine different kinds of bimodal scalar spectra are used to study the effects of the relative energy ratio and the peak frequency separation between the low and high frequency wave fields on the wave height distribution. Observed results are compared with predictions of probabilistic models adopted in practice. Comparisons of the empirical data with relevant probabilistic models reveals that the Rayleigh model systematically overestimates the number of observed wave heights larger than the mean wave height, except for one of the cases analyzed. None of the models used to predict the observed exceedance probabilities is able to characterize adequately all cases of bimodal sea states examined here.

scholarly journals PREDICTION METHOD FOR THE WAVE HEIGHT DISTRIBUTION OEF THE WESTERN COAST OE TAIWAN

1984 ◽  
Vol 1 (19) ◽  
pp. 31 ◽  
Author(s):  
Frederick L.W. Tang ◽  
Jea-Tzyy Juang
Keyword(s):  
Wave Height ◽  
Prediction Method ◽  
Distribution Model ◽  
Western Coast ◽  
Height Distribution ◽  
North West ◽  
The North ◽  
Wave Height Distribution ◽  
Wave Heights ◽  
The Western Pacific

Taiwan Strait locates on the continental shelf of the western Pacific Ocean. The water depth is less than 100 meters. Furthermore, the bathemetry of the eastern side namely the offing of western coast of Taiwan shoals gradually. In consequence, in case of the wind "blows from the north to south, waves in the deeper part of the strait refract to he north west direction while they are approaching the shore and local waves directly generated by the wind still keep the same direction of the wind. The situation is shown in Figure 1. Erom September to April of the next year, anticyclones come from Mongolia causes monsoon in this area. The wind velocity in the monsoon sometimes exceeds 20 meters per second, but it is arround 10 meters per second in general. Howerer, the duration of winds over 5 meters per second has been recorded more than 50 days. Engineering works such as towing caissons for building breakwater as well as dredging offshore have to be done in these days. Furthermore, navigation operations should not be stopped unless the wind is too strong. Of course, waves are forecast every day, however, more precise information about the probability of the occurrence of certain wave height is of great significance. In last conference, the authors submitted a probability density function of wave heights in this area. This distribution model is to be remended by considering energy loss in this paper, and concrete forecasting procedure is submitted for engineering and navigation practice.

A Model for Long-Term Distribution of Wave Induced Loads in Steep and Breaking Shallow Water Waves

2012 ◽  
Author(s):  
Hans Fabricius Hansen ◽  
Iris Pernille Lohmann ◽  
Jacob Tornfeldt Sørensen ◽  
Flemming Schlütter
Keyword(s):  
Transfer Function ◽  
Shallow Water ◽  
Wave Height ◽  
Wave Breaking ◽  
Extreme Value Analysis ◽  
Offshore Wind Turbine ◽  
Height Distribution ◽  
Wave Load ◽  
Wave Induced

A new approach to determine the design wave load on bottom-fixed structures in shallow water breaking waves is presented here. The method takes into account the effects that wave breaking has on both the wave height distribution and the wave induced loads on the structure. The loads on offshore wind turbine foundations in irregular seas with a significant amount of wave breaking are modeled in a physical wave tank. The loads are related to wave characteristics as steepness and Ursell number, and a non-linear transfer function between wave height/period and wave load is established. Characteristic historical load events are now established by combining the transfer function with a record of the wave climate at the site. The latter is taken from a hindcast database, but could also come from site measurements. The long-term distribution of the load is estimated by adopting traditional extreme value analysis techniques to the historical characteristic loads.

scholarly journals WAVE HEIGHT DISTRIBUTION AROUND PERMEABLE BREAKWATERS

1978 ◽  
Vol 1 (16) ◽  
pp. 39 ◽  
Author(s):  
Shintaro Hotta
Keyword(s):  
Shallow Water ◽  
Wave Height ◽  
Water Depth ◽  
Height Distribution ◽  
Water Basin ◽  
Wave Height Distribution ◽  
Incident Waves

By superimposing solutions due to Sommerfeld, a calculation was made to obtain the wave height distribution around permeable breakwaters in a constant water depth. The cases dealt with were a semi-infinite breakwater, a single relatively large gap in a long breakwater and a single detached breakwater all with incident waves normal to the breakwater. Some cases were verified through experiments in a shallow water basin.

scholarly journals WAVE HEIGHT DISTRIBUTION AND WAVE GROUPING IN SURF ZONE

1982 ◽  
Vol 1 (18) ◽  
pp. 4 ◽  
Author(s):  
Hajime Mase ◽  
Yuichi Iwagaki
Keyword(s):  
Wave Height ◽  
Surf Zone ◽  
Irregular Waves ◽  
Wave Transformation ◽  
Height Distribution ◽  
Frequency Distributions ◽  
Irregular Wave ◽  
Wave Height Distribution ◽  
Wave Heights ◽  
Deep Water Wave

The main purpose of this paper is to propose a model for prediction of the spatial distributions of representative wave heights and the frequency distributions of wave heights of irregular waves in shallow-water including the surf zone. In order to examine the validity of the model, some experiments of irregular wave transformation have been made. In addition, an attempt has been made to clarify the spatial distribution of wave grouping experimentally. Especially the present paper focuses finding the effects of the bottom slope and the deep-water wave steepness on the wave height distribution and wave grouping.

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