scholarly journals Wave length and celerity downstream from a hydraulic jump

RBRH ◽  
2019 ◽  
Vol 24 ◽  
Author(s):  
Ana Paula Gomes ◽  
Eduardo Pivatto Marzec ◽  
Luiz Augusto Magalhães Endres
Keyword(s):  
Dispersion Equation ◽  
Hydraulic Jump ◽  
Wave Length ◽  
Vortex Formation ◽  
Wave Period ◽  
Time Interval ◽  
Significant Wave ◽  
Wave Characteristics ◽  
Wave Celerity

ABSTRACT The wave period, i. e., the time interval which corresponds to a complete oscillation, is an important parameter of wave characterization. It allows the estimation of other important wave characteristics such as the length and celerity. This study aims at describing the results of a relationship among the significant, mean, and peak periods of waves generated downstream from a hydraulic jump. The frequency of vortex formation in the roller region within the hydraulic jump was used. Besides those relationships, wave lengths were also determined by the dispersion equation by considering the wave-current overlapping effect in order to identify the wave celerity. Estimated results of wave celerity were compared to their experimental results. Our findings allowed us to identify that the significant wave period was the most representative period for the characterization of a wave downstream from a hydraulic jump.

Potential Changes in the Joint Probabilistic Description of the North Atlantic Wave Climate

2018 ◽  
Author(s):  
Elzbieta M. Bitner-Gregersen ◽  
Odin Gramstad
Keyword(s):  
Wave Height ◽  
21St Century ◽  
North Atlantic ◽  
Significant Wave Height ◽  
Wave Climate ◽  
Wave Period ◽  
Simultaneous Occurrence ◽  
Significant Wave ◽  
The Past ◽  
Wave Characteristics

Climate changes include natural climate variability and anthropogenic climate change. The latter is leading to global warming and causes changes in metocean conditions. For most marine structures waves represent the dominant environmental load. Therefore, projections of changes of wave characteristics in the 21st century are crucial with respect to design and marine operations. The study investigates potential changes in simultaneous occurrence of significant wave height and spectral wave period in twelve North Atlantic locations by comparing the past and future wave climate. Two IPCC emission scenarios, with radiative forcing of 4.5 and 8.5 W/m2 by the end of the 21st century, have been selected to project future wave conditions. The third generation (3G) wave model WAM with a resolution of 50 km is used to simulate waves. The model has been forced with winds obtained from six CMIP5 climate models for the historical period 1971–2000 and the future period 2071–2100 for the two emissions scenarios. Wave climate projections obtained from one climate model and one ensemble member are presented herein to indicate potential changes in extreme wave characteristics derived from the long-term joint probabilistic model of significant wave height and spectral wave period. Deviations between the past and future wave climate are shown, given attention to the shape of the joint distribution and wave steepness. Uncertainties associated with the presented results are discussed.

Characterization of Flood Waves by Rating Curves

1997 ◽  
Vol 28 (1) ◽  
pp. 51-64 ◽  
Author(s):  
S.K. Mishra ◽  
M.K. Jain ◽  
S.M. Seth
Keyword(s):  
Phase Difference ◽  
Central India ◽  
Wave Number ◽  
Wave Characteristics ◽  
Travel Wave ◽  
Frame Work ◽  
Rating Curves ◽  
Exact Relationship ◽  
Flood Waves

The flood waves are characterized within the frame-work of loop (or hysteresis) of rating curves. The National Weather Service's Dam Break Flood Forecasting Model is used to generate the flood waves in the downstream valley of the Bargi dam located in Central India. The quantified hystereses, η, of non-dimensional rating curves are related with the corresponding flood wave characteristics, viz., speed of travel, wave number, phase difference, and attenuation. The analysis has led to the development of an exact relationship between η and phase difference. Using the concept of wave zoning, the better performance of the hysteresis based criteria compared with the available criteria is verified using Convex and Muskingum-Cunge routing in the wave zones. η limits are specified for the applicability of these simplified routing models. Furthermore, the envisaged applications of the based analysis are introduced.

Characterization of Structural Properties in High Reynolds Hydraulic Jump Based on CFD and Physical Modeling Approaches

2020 ◽  
Vol 146 (12) ◽  
pp. 04020079 ◽  
Author(s):  
Juan Francisco Macián-Pérez ◽  
Arnau Bayón ◽  
Rafael García-Bartual ◽  
P. Amparo López-Jiménez ◽  
Francisco José Vallés-Morán
Keyword(s):  
Structural Properties ◽  
Physical Modeling ◽  
Hydraulic Jump ◽  
Modeling Approaches ◽  
High Reynolds

scholarly journals Physical Modelling of the Effect on the Wave Field of the WaveCat Wave Energy Converter

2021 ◽  
Vol 9 (3) ◽  
pp. 309
Author(s):  
James Allen ◽  
Gregorio Iglesias ◽  
Deborah Greaves ◽  
Jon Miles
Keyword(s):  
Wave Height ◽  
Wave Energy ◽  
Significant Wave Height ◽  
Wedge Angle ◽  
Wave Energy Converter ◽  
Wave Period ◽  
Surface Elevation ◽  
Energy Converter ◽  
Significant Wave ◽  
Model Scale

The WaveCat is a moored Wave Energy Converter design which uses wave overtopping discharge into a variable v-shaped hull, to generate electricity through low head turbines. Physical model tests of WaveCat WEC were carried out to determine the device reflection, transmission, absorption and capture coefficients based on selected wave conditions. The model scale was 1:30, with hulls of 3 m in length, 0.4 m in height and a freeboard of 0.2 m. Wave gauges monitored the surface elevation at discrete points around the experimental area, and level sensors and flowmeters recorded the amount of water captured and released by the model. Random waves of significant wave height between 0.03 m and 0.12 m and peak wave periods of 0.91 s to 2.37 s at model scale were tested. The wedge angle of the device was set to 60°. A reflection analysis was carried out using a revised three probe method and spectral analysis of the surface elevation to determine the incident, reflected and transmitted energy. The results show that the reflection coefficient is highest (0.79) at low significant wave height and low peak wave period, the transmission coefficient is highest (0.98) at low significant wave height and high peak wave period, and absorption coefficient is highest (0.78) when significant wave height is high and peak wave period is low. The model also shows the highest Capture Width Ratio (0.015) at wavelengths on the order of model length. The results have particular implications for wave energy conversion prediction potential using this design of device.

scholarly journals COMPARISON BETWEEN THE RESULTS OF LITTORAL-DRIFT COMPUTATIONS AND CUBATURE OF DEPOSITS IN A DREDGED CHANNEL

1974 ◽  
Vol 1 (14) ◽  
pp. 42
Author(s):  
V.F. Motta ◽  
J.V. Bandeira
Keyword(s):  
Time Interval ◽  
Littoral Drift ◽  
Monthly Basis ◽  
Wave Characteristics ◽  
Order Of Magnitude ◽  
Annual Volume ◽  
Offshore Oil ◽  
Remarkable Agreement

The total annual volume of littoral drift on either side of the mouth of Sergipe estuary, in the Northeast of Brazil, has been de_ termined by applying Caldwell's, Castanho's and Bijker's methods to the wave characteristics that had been recorded at a twenty-metre depth of water, over a whole year, for the design of an offshore oil terminal. The three computation methods yielded the same order of maj> nitude which was found to amount to about 80000Om^/year. The dominant drift is s outhwes tward, and its predicted amount is 660000m-*/year. It was also found that although the three methods lead to total re suits of the same order of magnitude, they do not agree as to the vari^ ation of littoral drift over the year for the s ame waves. An eight-metre deep shipping channe 1 has been dredgedaccross the bar. The channel was surveyed in December 1971, August and Decem ber 1972, and a cubature of the deposits was made after the littoraldrift computations had been carried out. As the latter had been per formed on a monthly basis, a comparison became possible between pre dieted and actual volumes of deposits for the same lengths of time. The predicted volumes for the whole year were found to be from 34 to 46% greater than the actual results. However, for the time interval August-December 1972 a remarkable agreement was found be^ tween predicted and actual results.

Comparison of Bivariate Models of the Distribution of Significant Wave Height and Peak Wave Period

2007 ◽  
Author(s):  
Catarina S. Soares ◽  
C. Guedes Soares
Keyword(s):  
Wave Height ◽  
Significant Wave Height ◽  
Bivariate Normal Distribution ◽  
Wave Period ◽  
Peak Period ◽  
Data Set ◽  
Significant Wave ◽  
The North ◽  
Bivariate Models ◽  
The North Sea

This paper presents the results of a comparison of the fit of three bivariate models to a set of 14 years of significant wave height and peak wave period data from the North Sea. One of the methods defines the joint distribution from a marginal distribution of significant wave height and a set of distributions of peak period conditional on significant wave height. Other method applies the Plackett model to the data and the third one applies the Box-Cox transformation to the data in order to make it approximately normal and then fits a bivariate normal distribution to the transformed data set. It is shown that all methods provide a good fit but each one have its own strengths and weaknesses, being the choice dependent on the data available and applications in mind.

Final characterization of InLambda delay standards for supplementary time interval comparison

2018 ◽  
Author(s):  
Albin Czubla ◽  
Piotr Szterk ◽  
Roman Osmyk ◽  
Borut Pinter ◽  
Rado Lapuh ◽  
...  
Keyword(s):  
Time Interval ◽  
Interval Comparison
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