Correlation Analysis between Wave Parameters using Wave Data Observed in HeMOSU-1&2

Abstract. The performance of two methods for quantifying whitecapping dissipation incorporated in the SWAN wave model is evaluated for waves generated along and off the U.S. East Coast under energetic winter storms with a predominantly westerly wind. Parameterizing the whitecapping effect can be done using the Komen-type schemes, which are based on mean spectral parameters, or the saturation-based (SB) approach of van der Westhuysen (2007), which is based on local wave parameters and the saturation level concept of the wave spectrum (we use Komen and Westhuysen to denote these two approaches). Observations of wave parameters and frequency spectra at four NDBC buoys are used to evaluate simulation results. Model-data comparisons show that when using the default parameters in SWAN, both Komen and Westhuysen methods underestimate wave height. Simulations of mean wave period using the Komen method agree with observations, but those using the Westhuysen method are substantially lower. Examination of source terms shows that the Westhuysen method underestimates the total energy transferred into the wave action equations, especially in the lower frequency bands that contain higher spectral energy. Several causes for this underestimation are identified. The primary reason is the difference between the wave growth conditions along the East Coast during winter storms and the conditions used for the original whitecapping formula calibration. In addition, some deficiencies in simulation results are caused along the coast by the slanting fetch effect that adds low-frequency components to the 2-D wave spectra. These components cannot be simulated partly or entirely by available wind input formulations. Further, the effect of boundary layer instability that is not considered in the Komen and Westhuysen whitecapping wind input formulas may cause additional underestimation.

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Gap-Filling and Predicting Wave Parameters Using Support Vector Regression Method

Volume 6: Ocean Engineering ◽

10.1115/omae2011-49814 ◽

2011 ◽

Author(s):

Maziar Golestani ◽

Mostafa Zeinoddini

Keyword(s):

Support Vector Regression ◽

Wave Height ◽

Significant Wave Height ◽

Rational Design ◽

Wave Spectrum ◽

Support Vector ◽

Wave Spectra ◽

Significant Wave ◽

Wave Parameters ◽

Data Gaps

Knowledge of relevant oceanographic parameters is of utmost importance in the rational design of coastal structures and ports. Therefore, an accurate prediction of wave parameters is especially important for safety and economic reasons. Recently, statistical learning methods, such as Support Vector Regression (SVR) have been successfully employed by researchers in problems such as lake water level predictions, and significant wave height prediction. The current study reports potential application of a SVR approach to predict the wave spectra and significant wave height. Also the capability of the model to fill data gaps was tested using different approaches. Concurrent wind and wave records (standard meteorological and spectral density data) from 4 stations in 2003, 2007, 2008 and 2009 were used both for the training the SVR system and its verification. The choice of these four locations facilitated the comparison of model performances in different geographical areas. The SVR model was then used to obtain predictions for the wave spectra and also time series of wave parameters (separately for each station) such as its Hs and Tp from spectra and wind records. New approach was used to predict wave spectra comparing to similar studies. Reasonably well correlation was found between the predicted and measured wave parameters. The SVR model was first trained and tested using various methods for selecting training data. Also different values for SVM parameters (e.g. tolerance of termination criterion, cost, and gamma in kernel function) were tested. The best possible results were obtained using a Unix shell script (in Linux) which automatically implements different values for different input parameters and finds the best regression by calculating statistical scores like correlation of coefficient, RMSE, bias and scatter index. Finally for a better understanding of the results, Quantile-Quantile plots were produced. The results show that SVR can be successfully used for prediction of Hs and wave spectrum out of a series of wind and spectral wave parameters inputs. Also it was noticed that SVR is an efficient tool to be used when data gaps are present in the data.

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Wave directional measurement in Patos Lagoon, RS, Brazil

RBRH ◽

10.1590/2318-0331.011716053 ◽

2017 ◽

Vol 22 (0) ◽

Author(s):

Natália Lemke ◽

◽

Lauro Julio Calliari ◽

José Antônio Scotti Fontoura ◽

Déborah Fonseca Aguiar

Keyword(s):

Wave Height ◽

Significant Wave Height ◽

Wave Climate ◽

Coastal Protection ◽

Peak Period ◽

Patos Lagoon ◽

Significant Wave ◽

Wave Parameters ◽

Wave Heights ◽

Significant Wave Heights

ABSTRACT The wave climate characterization in coastal environments is essentially important to oceanography and coastal engineering professionals regarding coastal protection works. Thus, this study aims to determine the most frequent wave parameters (significant wave height, peak period and peak direction) in Patos Lagoon during the period of operation of a directional waverider buoy (from 01/27/2015 to 06/30/2015). The equipment was moored at approximately 14 km from the São Lourenço do Sul coast at the geographic coordinates of 31º29’06” S and 51º55’07” W, with local depth of six meters, registering significant wave height, peak period and peak direction time series. During the analyzed period, the greatest wave frequencies corresponded to short periods (between 2 and 3.5 seconds) and small values of significant wave heights (up to 0.6 meters), with east peak wave directions. The largest wave occurrences corresponded to east peak wave directions (33.3%); peak wave periods between 2.5 and 3 seconds (25.6%) and between 3 and 3.5 seconds (22.1%); and to significant wave heights of up to 0.3 meters (41.2%) and from 0.3 to 0.6 meters (38%). This research yielded unprecedented findings to Patos Lagoon by describing in detail the most occurring wave parameters during the analyzed period, establishing a consistent basis for several other studies that might still be conducted by the scientific community.

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Bayesian Estimation of Directional Wave-Spectrum Using Vessel Movements and Wave-Probes: Proposal and Preliminary Experimental Validation

Volume 1: Offshore Technology ◽

10.1115/omae2017-61241 ◽

2017 ◽

Author(s):

Felipe Lopes de Souza ◽

Eduardo Aoun Tannuri ◽

Pedro Cardozo de Mello ◽

Guilherme Franzini ◽

Jordi Mas-Soler ◽

...

Keyword(s):

Linear Model ◽

Wave Spectrum ◽

Estimation Method ◽

Scale Model ◽

Spectral Energy ◽

Peak Period ◽

Directional Wave Spectrum ◽

Wave Basin ◽

Directional Wave ◽

Probe Response

The measurement of the directional wave spectrum in oceans has been done by different approaches, mainly wave-buoys, satellite imagery and radar technologies; these methods, however, present some inherent drawbacks, e.g., difficult maintenance, low-resolution around areas of interest and high-cost. In order to overcome those problems, recent works in the area proposed a motion-based estimation procedure using the vessel, or the floating facility, as a wave sensor, what was called wave-buoy analogy. Despite of solving the issues, the solution is still incomplete, since it suffers from low estimation capabilities of the spectral energy below the cut-off period of the systems, around eight seconds, a frequency range that is responsible for the drift effects, that are critical for operation planning and dynamic positioning. This work studies the usage of wave-probes installed on the hull of a moored vessel to enhance the estimation capabilities of the motion-based strategy, using a high-order estimation method based on Bayesian statistics. The proposal is founded on the asymptotical response of the oceanic systems facing low period waves, which starts to behave like a wall, reflecting all the incoming energy, i.e., the worst the motion-based estimation is, the better the wave-elevation based estimation should be. Firstly, the measurements from the wave-probes are incorporated to the dynamic system of the vessel as new degrees-of-freedom, using a linear model extension, thus the Bayesian method can be expanded without additional reasoning. Secondly, the linear model hypothesis and the possible improvements are validated by experiments conducted in a wave-basin with a scale model of a moored FPSO-VLCC, concluding that the approach is able to improve not only the estimation of spectra with low peak period, but also the estimation in the entire range of expected spectra, mainly the significant height and the peak period properties. Lastly, some drawbacks are discussed, as the effect of the non-linear roll movement, which must be taken in account when calculating the wave-probe response; and the poor mean-direction estimation capability in some particular wave directions and low peak periods, in which even the vessel motions allied with the wave-probe response are not able to provide the proper direction discrimination.

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Task-Related Rogue Waves Embedded in Extreme Seas

21st International Conference on Offshore Mechanics and Arctic Engineering, Volume 4 ◽

10.1115/omae2002-28459 ◽

2002 ◽

Cited By ~ 5

Author(s):

Gu¨nther F. Clauss

Keyword(s):

Wave Height ◽

Wave Train ◽

Random Phase ◽

Rogue Waves ◽

Initial Guess ◽

New Technique ◽

Discrete Wavelet ◽

Peak Period ◽

Laboratory Conditions ◽

Starting Point

This paper describes a new technique for the generation of tailored design wave sequences in extreme seas which are simulated under laboratory conditions. The wave field is fitted to predetermined global and local target characteristics defined in terms of significant wave height, peak period as well as wave height, crest height, and period of individual waves. The generation procedure is based on two steps: Firstly, a linear approximation of the desired wave train is computed by a Sequential Quadratic Programming (SQP) method which optimises an initially random phase spectrum for a given variance spectrum. The wave board motion derived from this initial guess serves as starting point for directly fitting the physical wave train to the target parameters. The subplex method developed by Rowan (1990) is applied to improve systematically a certain time frame of the wave board motion which is responsible for the evolution of the design wave sequence. The discrete wavelet transformation is introduced to reduce significantly the number of free variables to be considered in the fitting problem. Wavelet analysis allows to localise efficiently the relevant information of the electrical control signal of the wave maker in time and frequency scale. Nonlinear free surface effects, even wave breaking are included in the fitting process since the simulation of the physical wave evolution under laboratory conditions is an integral part of the new technique. This feature is especially important for simulating experimentally wave/structure interactions in rogue waves and critical wave groups. As an illustration of this technique the Draupner “New Year Wave” is simulated and generated in a physical model wave tank. Also a “Three Sisters” wave sequence with succeeding wave heights Hs … 2Hs … Hs, embedded in an extreme sea, is synthesised.

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The Taming of the Shrew: Tailoring Freak Wave Sequences for Seakeeping Tests

Journal of Ship Research ◽

10.5957/jsr.2008.52.3.194 ◽

2008 ◽

Vol 52 (03) ◽

pp. 194-226

Author(s):

Günther F. Clauss

Keyword(s):

Wave Height ◽

Wave Train ◽

Random Phase ◽

Offshore Structures ◽

Green Water ◽

Discrete Wavelet ◽

Peak Period ◽

Worst Case ◽

Apparent Lack ◽

Starting Point

If you want to build a ship, don't drum up people together to collect woodand don't assign them tasks and work but rather teach them to long for the endless immensity of the sea.___Antoine de Saint-Exupery (1900–1944)___The basic law of the seaway is the apparent lack of any law.___Lord Rayleigh___Based on the wave focusing technique for the generation of task-related wave packets, a new technique is proposed for the synthesization of tailored design wave sequences in extreme seas. The physical wave field is fitted to predetermined global and local target characteristics designed in terms of significant wave height, peak period, as well as wave height, crest height, and period of individual waves. The generation procedure is based on two steps: First, a linear approximation of the desired wave train is computed by a sequential quadratic programming method that optimizes an initially random phase spectrum for a given variance spectrum. The wave board motion derived from this initial guess serves as a starting point for directly fitting the physical wave train to the target parameters. The subplex method is applied to improve systematically a certain time frame of the wave board motion, which is responsible for the evolution of the response-related design wave sequence. The discrete wavelet transform is introduced to reduce significantly the number of free variables to be considered in the fitting process. Wavelet analysis allows the efficient localization of the relevant information on the electrical control signal of the wave maker in time and frequency domain. As the presented technique permits the deterministic generation of design rogue wave sequences in extreme seas, it is well suited for investigating the mechanism of arbitrary wave-structure interactions, including capsizing, slamming, and green water as well as other survivability design aspects. Even worst case wave sequences, such as the Draupner New Year wave, can be modeled in the wave tank to analyze the evolution of these events and to evaluate the response of offshore structures under abnormal conditions. This procedure is illustrated by investigations of an offshore lift operation, of the behavior of a semisubmersible and an FPSO in tailored freak waves as well as the analysis of ship capsizing in deterministic wave sequences at selected target positions.

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Bayesian Estimation of Directional Wave-Spectrum Using Vessel Motions and Wave-Probes: Proposal and Preliminary Experimental Validation

Journal of Offshore Mechanics and Arctic Engineering ◽

10.1115/1.4039263 ◽

2018 ◽

Vol 140 (4) ◽

Cited By ~ 5

Author(s):

Felipe Lopes de Souza ◽

Eduardo Aoun Tannuri ◽

Pedro Cardozo de Mello ◽

Guilherme Franzini ◽

Jordi Mas-Soler ◽

...

Keyword(s):

Degrees Of Freedom ◽

Wave Spectrum ◽

Estimation Method ◽

Estimation Procedure ◽

Scale Model ◽

Spectral Energy ◽

Peak Period ◽

Directional Wave Spectrum ◽

Wave Basin ◽

Directional Wave

The measurement of the directional wave spectrum in oceans has been done by different approaches, mainly wave-buoys, satellite imagery and radar technologies; these methods, however, present some inherent drawbacks, e.g., difficult maintenance, low resolution around areas of interest and high cost. In order to overcome those problems, recent works proposed a motion-based estimation procedure using the vessel as a wave sensor; nevertheless, this strategy suffers from low-estimation capabilities of the spectral energy coming from periods lower than the cutoff period of the systems, which are important for the drift effect predictions. This work studies the usage of wave-probes installed on the hull of a moored vessel to enhance the estimation capabilities of the motion-based strategy, using a high-order estimation method based on Bayesian statistics. First, the measurements from the wave-probes are incorporated to the dynamic system of the vessel as new degrees-of-freedom (DOF); thus, the Bayesian method can be expanded without additional reasoning. Second, the proposal is validated by experiments conducted in a wave-basin with a scale model, concluding that the approach is able to improve not only the estimation of spectra with low peak period but also the estimation in the entire range of expected spectra. Finally, some drawbacks are discussed, as the effect of the nonlinear roll motion, which must be taken in account when calculating the wave-probe response; and the poor mean-direction estimation capability in some particular wave directions and low peak periods.

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Application of Cross-correlation Analysis Method for Measurement of the Fluid Flow Rate Based on X-ray Radiation

Journal of Nano- and Electronic Physics ◽

10.21272/jnep.11(1).01025 ◽

2019 ◽

Vol 11 (1) ◽

pp. 01025-1-01025-5 ◽

Cited By ~ 1

Author(s):

N. A. Borodulya ◽

◽

R. O. Rezaev ◽

S. G. Chistyakov ◽

E. I. Smirnova ◽

...

Keyword(s):

Fluid Flow ◽

Correlation Analysis ◽

Flow Rate ◽

Cross Correlation ◽

Fluid Flow Rate ◽

Analysis Method ◽

X Ray ◽

Cross Correlation Analysis ◽

Correlation Analysis Method

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UNDERWATER BARRED BEACH PROFILE TRANSFORMATION UNDER DIFFERENT WAVES CONDITIONS

Proceedings of International Conference "Managinag risks to coastal regions and communities in a changinag world" (EMECS'11 - SeaCoasts XXVI) ◽

10.21610/conferencearticle_58b4315f60698 ◽

2017 ◽

Author(s):

Olga Kuznetsova ◽

Yana Saprykina ◽

Boris Divinsky ◽

...

Keyword(s):

Numerical Modelling ◽

Coastal Zone ◽

Wave Height ◽

Wave Energy ◽

Wave Period ◽

Beach Profile ◽

Infragravity Waves ◽

Wave Parameters ◽

Mean Wave Period

Based on numerical modelling evolution of beach under waves with height 1,0-1,5 m and period 7,5 and 10,6 sec as well as spectral wave parameters varying cross-shore analysed. The beach reformation of coastal zone relief is spatially uneven. It is established that upper part of underwater beach profile become terraced and width of the terrace is in direct pro-portion to wave height and period on the seaward boundary but inversely to angle of wave energy spreading. In addition it was ascertain that the greatest transfiguration of profile was accompanied by existence of bound infragravity waves, smaller part of its energy and shorter mean wave period as well as more significant roller energy.

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Chemometric Analysis for the Classification of some Groups of Drugs with Divergent Pharmacological Activity on the Basis of some Chromatographic and Molecular Modeling Parameters

Combinatorial Chemistry & High Throughput Screening ◽

10.2174/1386207321666180129102149 ◽

2018 ◽

Vol 21 (2) ◽

pp. 125-137

Author(s):

Jolanta Stasiak ◽

Marcin Koba ◽

Marcin Gackowski ◽

Tomasz Baczek

Keyword(s):

Correlation Analysis ◽

Pharmacological Activity ◽

Correlation Coefficients ◽

Principal Component ◽

Cardiovascular Drugs ◽

New Drugs ◽

Analgesic Drugs ◽

Starting Point ◽

Chromatographic Parameters

Aim and Objective: In this study, chemometric methods as correlation analysis, cluster analysis (CA), principal component analysis (PCA), and factor analysis (FA) have been used to reduce the number of chromatographic parameters (logk/logkw) and various (e.g., 0D, 1D, 2D, 3D) structural descriptors for three different groups of drugs, such as 12 analgesic drugs, 11 cardiovascular drugs and 36 “other” compounds and especially to choose the most important data of them. Material and Methods: All chemometric analyses have been carried out, graphically presented and also discussed for each group of drugs. At first, compounds’ structural and chromatographic parameters were correlated. The best results of correlation analysis were as follows: correlation coefficients like R = 0.93, R = 0.88, R = 0.91 for cardiac medications, analgesic drugs, and 36 “other” compounds, respectively. Next, part of molecular and HPLC experimental data from each group of drugs were submitted to FA/PCA and CA techniques. Results: Almost all results obtained by FA or PCA, and total data variance, from all analyzed parameters (experimental and calculated) were explained by first two/three factors: 84.28%, 76.38 %, 69.71% for cardiovascular drugs, for analgesic drugs and for 36 “other” compounds, respectively. Compounds clustering by CA method had similar characteristic as those obtained by FA/PCA. In our paper, statistical classification of mentioned drugs performed has been widely characterized and discussed in case of their molecular structure and pharmacological activity. Conclusion: Proposed QSAR strategy of reduced number of parameters could be useful starting point for further statistical analysis as well as support for designing new drugs and predicting their possible activity.

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