Bibliographies thématiques / Wave loading models

Littérature scientifique sur le sujet « Wave loading models »

Auteur : Grafiati
Publié le 10 mars 2023

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Articles de revues sur le sujet "Wave loading models"

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Mockutė, Agota, Enzo Marino, Claudio Lugni et Claudio Borri. « Comparison of Nonlinear Wave-Loading Models on Rigid Cylinders in Regular Waves ». Energies 12, no 21 (23 octobre 2019) : 4022. http://dx.doi.org/10.3390/en12214022.

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Monopiles able to support very large offshore wind turbines are slender structures susceptible to nonlinear resonant phenomena. With the aim to better understand and model the wave-loading on these structures in very steep waves where ringing occurs and the numerical wave-loading models tend to lose validity, this study investigates the distinct influences of nonlinearities in the wave kinematics and in the hydrodynamic loading models. Six wave kinematics from linear to fully nonlinear are modelled in combination with four hydrodynamic loading models from three theories, assessing the effects of both types of nonlinearities and the wave conditions where each type has stronger influence. The main findings include that the nonlinearities in the wave kinematics have stronger influence in the intermediate water depth, while the choice of the hydrodynamic loading model has larger influence in deep water. Moreover, finite-depth FNV theory captures the loading in the widest range of wave and cylinder conditions. The areas of worst prediction by the numerical models were found to be the largest steepness and wave numbers for second harmonic, as well as the vicinity of the wave-breaking limit, especially for the third harmonic. The main cause is the non-monotonic growth of the experimental loading with increasing steepness due to flow separation, which leads to increasing numerical overpredictions since the numerical wave-loading models increase monotonically.
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Pitchforth, D. J., T. J. Rogers, U. T. Tygesen et E. J. Cross. « Grey-box models for wave loading prediction ». Mechanical Systems and Signal Processing 159 (octobre 2021) : 107741. http://dx.doi.org/10.1016/j.ymssp.2021.107741.

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Ahmad, Sayyid Zainal Abidin Syed, Mohd Khairi Abu Husain, Noor Irza Mohd Zaki, Mohd Hairil Mohd et Gholamhossein Najafian. « Comparison of Various Spectral Models for the Prediction of the 100-Year Design Wave Height ». MATEC Web of Conferences 203 (2018) : 01020. http://dx.doi.org/10.1051/matecconf/201820301020.

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Offshore structures are exposed to random wave loading in the ocean environment, and hence the probability distribution of the extreme values of their response to wave loading is required for their safe and economical design. In most cases, the dominant load on offshore structures is due to wind-generated random waves where the ocean surface elevation is defined using appropriate ocean wave energy spectra. Several spectral models have been proposed to describe a particular sea state that is used in the design of offshore structures. These models are derived from analysis of observed ocean waves and are thus empirical in nature. The spectral models popular in the offshore industry include Pierson-Moskowitz spectrum and JONSWAP spectrum. While the offshore industry recognizes that different methods of simulating ocean surface elevation lead to different estimation of design wave height, no systematic investigation has been conducted. Hence, the aim of this study is to investigate the effects of predicting the 100-year responses from various wave spectrum models. In this paper, the Monte Carlo time simulation (MCTS) procedure has been used to compare the magnitude of the 100-year extreme responses derived from different spectral models. Additionally, the linear random wave theory (LRWT) was implemented to simulate the offshore structural responses due to random wave loading. The models have been tested for three different environmental conditions represented by Hs = 15m, 10m and 5m respectively. The accuracy of the predictions of the 100-year responses from Pierson-Moskowitz and JONSWAP spectrums will then be investigated.
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Lindt, John W. van de, Rakesh Gupta, Daniel T. Cox et Jebediah S. Wilson. « Wave Impact Study on a Residential Building ». Journal of Disaster Research 4, no 6 (1 décembre 2009) : 419–26. http://dx.doi.org/10.20965/jdr.2009.p0419.

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Recent natural disasters around the world including both tsunamis and hurricanes, have highlighted the inability of wood buildings to withstand wave and surge loading during these extreme events. Little is known about the interaction between coastal residential light-frame wood buildings and wave and surge loading because often little is left of the buildings. This leaves minimal opportunity for forensic investigations. This paper summarizes the results of a study whose objective was to begin to better understand the interaction between North American style residential structures and wave loading. To do this, one-sixth scale residential building models typical of North American coastal construction, were subjected to tsunami wave bores generated from waves of heights varying from 10 cm to 60 cm. The lateral force produced by the wave bores were, as expected, found to vary nonlinearly with parent wave height.
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Raovic, Nevena, Otto Anker Nielsen et Carlo Giacomo Prato Carlo Giacomo Prato. « DYNAMIC QUEUING TRANSMISSION MODEL FOR DYNAMIC NETWORK LOADING ». Transport 32, no 2 (13 juillet 2015) : 146–59. http://dx.doi.org/10.3846/16484142.2015.1062417.

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This paper presents a new macroscopic multi-class dynamic network loading model called Dynamic Queuing Transmission Model (DQTM). The model utilizes ‘good’ properties of the Dynamic Queuing Model (DQM) and the Link Transmission Model (LTM) by offering a DQM consistent with the kinematic wave theory and allowing for the representation of multiple vehicle classes, queue spillbacks and shock waves. The model assumes that a link is split into a moving part plus a queuing part, and p that traffic dynamics are given by a triangular fundamental diagram. A case-study is investigated and the DQTM is compared with single-class LTM, single-class DQM and multi-class DQM. Under the model assumptions, single-class models indicate that the LTM and the DQTM give similar results and that the shock wave property is properly included in the DQTM, while the multi-class models show substantially different travel times for two vehicle classes. Moreover, the results show that the travel time will be underestimated without considering the shock wave property.
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Fox, Colin, et Tim G. Haskell. « Ocean wave speed in the Antarctic marginal ice zone ». Annals of Glaciology 33 (2001) : 350–54. http://dx.doi.org/10.3189/172756401781818941.

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AbstractThe propagation of ocean waves in the marginal ice zone (MIZ) is investigated with the aim of determining whether the loading and scattering of waves by ice floes is significant. Measurements made using instrumented ice floes in the MIZ north of the Ross Sea, Antarctica, during June 1998 are used to determine the frequency-wavelength relationship for propagating ocean waves in that region. This measured-dispersion equation is related to the effective large-scale properties of the MIZ that occur in models for wave propagation and scattering. We present the measured wave speeds to enable estimation of the parameters in these models.
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Robertson, Amy, et Lu Wang. « OC6 Phase Ib : Floating Wind Component Experiment for Difference-Frequency Hydrodynamic Load Validation ». Energies 14, no 19 (8 octobre 2021) : 6417. http://dx.doi.org/10.3390/en14196417.

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A new validation campaign was conducted at the W2 Harold Alfond Ocean Engineering Laboratory at the University of Maine to investigate the hydrodynamic loading on floating offshore wind substructures, with a focus on the low-frequency contributions that tend to drive extreme and fatigue loading in semisubmersible designs. A component-level approach was taken to examine the hydrodynamic loads on individual parts of the semisubmersible in isolation and then in the presence of other members to assess the change in hydrodynamic loading. A variety of wave conditions were investigated, including bichromatic waves, to provide a direct assessment of difference-frequency wave loading. An assessment of the impact of wave uncertainty on the loading was performed, with the goal of enabling validation with this dataset of numerical models with different levels of fidelity. The dataset is openly available for public use and can be downloaded from the U.S. Department of Energy Data Archive and Portal.
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Bouyssy, V., et R. Rackwitz. « Polynomial Approximation of Morison Wave Loading ». Journal of Offshore Mechanics and Arctic Engineering 119, no 1 (1 février 1997) : 30–36. http://dx.doi.org/10.1115/1.2829042.

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For offshore structures with slender elements, the modeling of random wave loads by the Morison equation yields an equation of motion which has no analytical solution for response moments except in a few limiting cases. If polynomial approximations of the Morison drag loads are introduced, some procedures are available to obtain the stationary moments of the approximate response. If the response process is fitted by non-Gaussian models such as proposed by Winterstein (1988), the first four statistical moments of the response are necessary. The paper investigates how many terms should be included in the polynomial approximation of the Morison drag loading to accurately estimate the first four response moments. It is shown that a cubic approximation of the drag loading is necessary to accurately predict the response variance for any excitation. For the fit of the first four response moments, at least a fifth-order approximation appears necessary.
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Beltman, W. M., E. N. Burcsu, J. E. Shepherd et L. Zuhal. « The Structural Response of Cylindrical Shells to Internal Shock Loading ». Journal of Pressure Vessel Technology 121, no 3 (1 août 1999) : 315–22. http://dx.doi.org/10.1115/1.2883709.

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The internal shock loading of cylindrical shells can be represented as a step load advancing at constant speed. Several analytical models are available to calculate the structural response of shells to this type of loading. These models show that the speed of the shock wave is an important parameter. In fact, for a linear model of a shell of infinite length, the amplitude of the radial deflection becomes unbounded when the speed of the shock wave is equal to a critical velocity. It is evident that simple (static) design formulas are no longer accurate in this case. The present paper deals with a numerical and experimental study on the structural response of a thin aluminum cylindrical shell to shock loading. Transient finite element calculations were carried out for a range of shock speeds. The results were compared to experimental results obtained with the GALCIT 6-in. shock tube facility. Both the experimental and the numerical results show an increase in amplitude near the critical velocity, as predicted by simple steady-state models for shells of infinite length. However, the finite length of the shell results in some transient phenomena. These phenomena are related to the reflection of structural waves and the development of the deflection profile when the shock wave enters the shell.
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Bloom, Frederick. « Constitutive Models for Wave Propagation in Soils ». Applied Mechanics Reviews 59, no 3 (1 mai 2006) : 146–75. http://dx.doi.org/10.1115/1.2177685.

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A survey is provided of the various constitutive models that have been used to study the phenomena of wave propagation in soils. While different material models have been proposed for the response of soils, it is now generally understood that no single model may be used over the entire range of pressures which are typically studied. The constitutive models reviewed in this paper include a number of effective stress and multiphase models, the volume distribution function model, and various versions of the P−α model. Also discussed are classical elastic-plastic models, models possessing different elastic constants in loading and unloading, variable modulus models, and capped elastic-plastic models.
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Thèses sur le sujet "Wave loading models"

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Mockutė, Agota [Verfasser]. « Suitability of Wave Loading Models for Offshore Wind Turbine Monopiles in Rough Seas / Agota Mockute ». Düren : Shaker, 2020. http://nbn-resolving.de/urn:nbn:de:101:1-2020090605232739927321.

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Mockute, Agota [Verfasser]. « Suitability of Wave Loading Models for Offshore Wind Turbine Monopiles in Rough Seas / Agota Mockute ». Düren : Shaker, 2020. http://d-nb.info/1217164081/34.

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Jain, Jayesh R. « Homogenization Based Damage Models for Monotonic and Cyclic Loading in 3D Composite Materials ». The Ohio State University, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=osu1230431496.

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Kitchen, Ryan L. « Improving Steering Module Efficiency for Incremental Loading Finite Element Numeric Models ». Diss., CLICK HERE for online access, 2006. http://contentdm.lib.byu.edu/ETD/image/etd1248.pdf.

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Kowalczyk, Piotr Jozef. « Validation and application of advanced soil constitutive models in numerical modelling of soil and soil-structure interaction under seismic loading ». Doctoral thesis, Università ; degli studi di Trento, 2020. http://hdl.handle.net/11572/275675.

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This thesis presents validation and application of advanced soil constitutive models in cases of seismic loading conditions. Firstly, results of three advanced soil constitutive models are compared with examples of shear stack experimental data for free field response in dry sand for shear and compression wave propagation. Higher harmonic generation in acceleration records, observed in experimental works, is shown to be possibly the result of soil nonlinearity and fast elastic unloading waves. This finding is shown to have high importance on structural response, real earthquake records and reliability of conventionally employed numerical tools. Finally, short study of free field response in saturated soil reveals similar findings on higher harmonic generation. Secondly, two advanced soil constitutive models are used, and their performance is assessed based on examples of experimental data on piles in dry sand in order to validate the ability of the constitutive models to simulate seismic soil-structure interaction. The validation includes various experimental configurations and input motions. The discussion on the results focuses on constitutive and numerical modelling aspects. Some improvements in the formulations of the models are suggested based on the detailed investigation. Finally, the application of one of the advanced soil constitutive models is shown in regard to temporary natural frequency wandering observed in structures subjected to earthquakes. Results show that pore pressure generated during seismic events causes changes in soil stiffness, thus affecting the natural frequency of the structure during and just after the seismic event. Parametric studies present how soil permeability, soil density, input motion or a type of structure may affect the structural natural frequency and time for its return to the initial value. In addition, a time history with an aftershock is analysed to investigate the difference in structural response during the earthquake and the aftershock.
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Bailey, J. S. L. « Experimentally verified fluid loading models for slender horizontal cylinders in waves ». Thesis, University of Sussex, 2000. http://sro.sussex.ac.uk/id/eprint/737/.

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This thesis reports on research work aimed at improving methods for predicting the fluid loading on fixed- and compliant offshore structures in waves. In focusing on slender member fluid-interaction models, the limitations and uncertainties associated with the widely-used Morison equation are examined. An improved empirical model has been developed and tested extensively alongside the Morison equation, using real experimental data. This improved model gives a better representation of the frequency dependency of the fluid-loading coefficients: this is particularly important in compliant motion conditions where the so-called relative velocity concept still needs to be verified under carefully controlled experimental conditions. The model is based entirely on the use of linear wave kinematics, thus simplifying calibration in irregular conditions and avoiding the need for a consistent non-linear wave theory (which is still lacking). By appropriate adaptation the improved model can also be extended to include amplitude dependency in the loading coefficients. The Improved Model has been developed through an analysis of experimental data. For this purpose the experimental work was focused on a horizontal cylinder, at model scale, located in a wave tank at the University of Sussex. The fluid loading experienced by a fixed cylinder, in both regular and irregular waves conditions, was measured and examined in detail. In addition, a comprehensive study of the loading on compliant cylinders, in both regular and irregular waves, was undertaken. Extensive use was made of appropriate parameter estimation techniques with initial attention (using simulated data) given to their accuracy for use with noisy experimental measurements. The effects of subtle (but undesirable) tank characteristics were also carefully taken into account. The study shows that, for fixed horizontal cylinders, benefits can be clearly identified in using the improved model, with frequency dependent coefficients, over the frequency dependent Morison equation. Moreover, the study shows that the relative velocity concept is more appropriate for use with the improved model than with the Morison model.
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Matemu, Christian Hillary. « Development of a One-Way Coupled Diffraction/Trapped Air Model for Predicting Wave Loading on Bridge Superstructure Under Water Wave Attack ». UNF Digital Commons, 2018. https://digitalcommons.unf.edu/etd/823.

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In recent years, a number of researchers have applied various computational methods to study wind wave and tsunami forcing on bridge superstructure problems. Usually, these computational analyses rely upon application of computational fluid dynamic (CFD) codes. While CFD models may provide reasonable results, their disadvantage is that they tend to be computationally expensive. During this study, an alternative computational method was explored in which a previously-developed diffraction model was combined with a previously-developed trapped air model under worst-case wave loading conditions (i.e. when the water surface was at the same elevation as the bottom bridge chord elevation). The governing equations were solved using a finite difference algorithm in MATLAB for the case where the bridge was impacted by a single wave in two dimensions. Resultant inertial and drag water forces were computed by integrating water pressure contacting the bridge superstructure in the horizontal and vertical directions, while resultant trapped air forces (high-frequency oscillatory forces or sometimes called “slamming forces” in the literature) were computed by integrating air pressure along the bottom of the bridge deck in the vertical direction. The trapped air model was also used to compute the buoyancy force on the bridge due to trapped air. Results were compared with data from experiments that were conducted at the University of Florida in 2009. Results were in good agreement when a length-scale coefficient associated with the trapped air model was properly calibrated. The computational time associated with the model was only approximately one hour per bridge configuration, which would appear to be a significant improvement when compared with other computational technique
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Douglas, Steven. « Numerical Modeling of Extreme Hydrodynamic Loading and Pneumatic Long Wave Generation : Application of a Multiphase Fluid Model ». Thesis, Université d'Ottawa / University of Ottawa, 2015. http://hdl.handle.net/10393/34076.

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In this study, a three-dimensional two-phase (air and water) numerical solver is applied to investigate free surface flows. The first component aims to improve the overall understanding of the underlying physical mechanisms that occur during the interaction between turbulent hydraulic bores and simple structures. Data collected during large-scale physical experiments based on generating dam-break waves in a horizontal rectangular channel is used for comparing to the numerical results. An extensive sensitivity analysis on numerical parameters including spatial discretization and turbulence models is presented. Quantitative comparisons of numerical and experimental time series of water surface elevations, pressure, and net streamwise force exerted on the structure are used to validate the model. In the in-depth analysis, it is demonstrated that the model is able to simulate the pertinent aspects of the flow behaviour that occur during the interaction with good agreement. The numerical impulsive force generated at initial impact shows excellent agreement with the experimental results, particularly for the larger magnitudes bores considered. Since the numerical model treats the air as an incompressible media, the level of agreement observed between the experimental and numerical results suggests that the compressibility of the air in the leading edge of the bore during the physical testing had no significant effect on the measured impulsive force. The two-phase model was also able to capture the occurrence of a second transient spike in the force exerted on the structure when the initial runup collapsed back onto the incoming flow, trapping a pocket of air in the process. The model was further applied to investigate the effect of an initially quiescent layer of water in the downstream channel section on bore propagation characteristics and the subsequent interaction with the structure. It is demonstrated that for small nonzero values of initial downstream depth a substantial increase in bore depth occurs. However, further increases in the downstream depth did not appear have any significant effects. For the greatest downstream depth simulated, a considerable reduction in the hydrodynamic force is observed as a result of a more rapid closing of the wake that develops on the leeside of the structure. The second component of the study applies the same numerical solver to investigate a novel long wave generation technique for producing laboratory-scale tsunami waves. The concept is based on removing the air from the inside of a tank with a submerged outlet at the upstream end of the basin and releasing the water in a controlled manner. A similar procedure as described above was used to calibrate the numerical parameters to experimentally-measured wave heights and periods. To model the influence of the pneumatic valves mounted on top of the upstream chamber, time-varying pressure boundary conditions are developed to regulate and control the pressure inside the tank. Quantitative and qualitative comparisons of the numerical and experimental results show good agreement and a high potential for the solver to be used for similar investigations. An analysis is performed to improve the existing understanding of the wave formation process. The model is also applied to modify test configurations that influence the waveform for which the results may be used to aid in making operating decisions for future tests or in the design of similar wave generating devices.
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Storhaug, Gaute. « Experimental investigation of wave induced vibrations and their effect on the fatigue loading of ships ». Doctoral thesis, Norwegian University of Science and Technology, Faculty of Engineering Science and Technology, 2007. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-1521.

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This thesis represents an attempt to reveal and explain the mysterious excitation sources which cause global wave induced vibrations of ships. The wave induced vibrations of the hull girder are referred to as springing when they are associated with a resonance phenomenon, and whipping when they are caused by a transient impact loading. Both phenomena excite the governing vertical 2-node mode and possibly higher order modes, and consequently increase the fatigue and extreme loading of the hull girder. These effects are currently disregarded in conventional ship design. The thesis focuses on the additional fatigue damage on large blunt ships.

The study was initiated by conducting an extensive literature study and by organizing an international workshop. The literature indicated that wave induced vibrations should be expected on any ship type, but full scale documentation (and model tests) was mainly related to blunt ships. While the theoretical investigation of whipping mostly focused on slender vessels with pronounced bow flare, full scale measurements indicated that whipping could be just as important for blunt as for slender ships. Moreover, all estimates dealing with the fatigue damage due to wave induced vibration based on full scale measurements before the year of 2000 were nonconservative due to crude simplifications. The literature on the actual importance of the additional fatigue contribution is therefore scarce.

The workshop was devoted to the wave induced vibrations measured onboard a 300m iron ore carrier. Full scale measurements in ballast condition were compared with numerical predictions from four state-of-the-art hydroelastic programs. The predicted response was unreliable, and the programs in general underestimated the vibration level. The excitation source was either inaccurately described or lacking. The prediction of sea state parameters and high frequency tail behavior of the wave spectra based on wave radars without proper setting and calibration was also questioned. The measurements showed that vibrations in ballast condition were larger than in the cargo condition, the vibration was more correlated with wind speed than wave height, head seas caused higher vibration levels than following seas, the vibration level towards beam seas decayed only slightly, and the damping ratio was apparently linear and about 0.5%. The additional vibration damage constituted 44% of the total measured fatigue loading in deck amidships in the North Atlantic iron ore trade, with prevailing head seas encountered in ballast condition.

Four hypotheses, which may contribute to explain the high vibration levels, were formulated. They include the effect of the steady wave field and the interaction with the unsteady wave field, amplification of short incident waves due to bow reflection, bow impacts including the exit phase and sum frequency excitation due to the bow reflection. The first three features were included in a simplified program to get an idea of the relative importance. The estimates indicated that the stem flare whipping was insignificant in ballast condition, but contributed in cargo condition. The whipping was found to be sensitive to speed. Simplified theory was employed to predict the speed reduction, which was about 5kn in 5m significant wave height. The estimated speed reduction was in fair agreement with full scale measurements of the iron ore carrier.

Extensive model tests of a large 4-segmented model of an iron ore carrier were carried out. Two loading conditions with three bow shapes were considered in regular and irregular waves at different speeds. By increasing the forward trim, the increased stem flare whipping was again confirmed to be of less importance than the reduced bottom forces in ballast condition. The bow reflection, causing sum frequency excitation, was confirmed to be important both in ballast and cargo condition. It was less sensitive to speed than linear springing. The second order transfer function amplitude displayed a bichromatic sum frequency springing (at resonance), which was almost constant independent of the frequency difference. The nondimensional monochromatic sum frequency springing response was even higher. The sum frequency pressure was mainly confined to the bow area. Surprisingly, for the sharp triangular bow with vertical stem designed to remove the sum frequency effect, the effect was still pronounced, although smaller. The reflection of incident waves did still occur.

In irregular head sea states in ballast condition whipping occurred often due to bottom bilge (flare) impacts, starting with the first vibration cycle in hogging. This was also observed in cargo condition, and evident in full scale. This confirmed that the exit phase, which was often inaccurately represented or lacking in numerical codes, was rather important. Flat bottom slamming was observed at realistic speeds, but the vibratory response was not significantly increased. Stern slamming did not give any significant vibration at realistic forward speeds.

The fatigue assessment showed that the relative importance of the vibration damage was reduced for increasing peak period, and secondly that it increased for increasing wave heights due to nonlinearities. All three bows displayed a similar behavior. For the sharp bow, the additional fatigue damage was reduced significantly in steep and moderate to small sea states, but the long term vibration damage was less affected. The effect of the bulb appeared to be small. The contribution of the vibration damage was reduced significantly with speed. For a representative North Atlantic iron ore trade with head sea in ballast and following sea in cargo condition the vibration damage reduced from 51% at full speed to 19% at realistic speeds. This was less than measured in full scale, but the damping ratio of 1-3.5% in model tests was too high, and the wave damage in following seas in cargo condition was represented by head sea states (to high wave damage due to too high encounter frequency). Furthermore, the contribution from vibration damage was observed to increase in less harsh environment from 19% in the North Atlantic to 26% in similarWorld Wide trade. This may also be representative for the effect of routing. The dominating wave and vibration damage came from sea states with a significant wave height of 5m. This was in agreement with full scale results. In ballast condition, the nonlinear sum frequency springing appeared to be more important than the linear springing, and the total springing seemed to be of equivalent importance as the whipping process, which was mainly caused by bottom bilge (flare) impacts. All three effects should be incorporated in numerical tools.

In full scale, the vibration response reached an apparently constant level as a function of wave height in both ballast and cargo condition in head seas. This behaviour could be explained by the speed reduction in higher sea states. The vibration level in cargo condition was 60-70% of the level in ballast condition. Although common knowledge implies that larger ships may experience higher springing levels due to a lower eigenfrequency, a slightly smaller ore carrier displayed a higher contribution from the vibration damage (57%) in the same trade, explained by about 1m smaller draft. Moreover, the strengthening of the larger ship resulted in a 10% increase of the 2-node eigenfrequency. The subsequent measurements confirmed that an increased hull girder stiffness was not an effective means to reduce the relative importance of the vibration damage.

The relative importance of the excitation sources causing wave induced vibration may differ considerably for a slender compared to a blunt vessel. Therefore, full scale measurements on a 300m container vessel were briefly evaluated. The damping ratio was almost twice as high as for several blunt ships, possibly due to significant contribution from the container stacks. The reduced relative importance of the vibration damage with increasing wave height for the iron ore carrier in full scale was opposite to the trend obtained for the container vessel. Less speed reduction in higher sea states was confirmed, and the whipping process was apparently relatively more important for the container vessel. Both for the blunt and slender ship of roughly 300m length, the total fatigue damage due to vibration was of similar importance as the conventional wave frequency damage. The contribution to fatigue damage from wave induced vibrations should be accounted for, for ships operating in harsh environment with limited effect of routing, especially when they are optimized with respect to minium steel weight.

The four hypotheses were all relevant in relation to wave induced vibrations on blunt ships. Further numerical investigation should focus on the sum frequency springing caused by bow reflection and the whipping impacts at the bow quarter. The wave amplification, steady wave elevation and the exit phase must be properly incorporated. When it comes to design by testing, an optimized model size must be selected (wall interaction versus short wave quality). The speed must be selected in combination with sea state. The wave quality must be monitored, and a realistic damping ratio should be confirmed prior to testing. For the purpose of investigating sum frequency excitation, a large restrained bow model tested in higher waves may be utilized to reduce uncertainties in the small measured pressures.

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Liang, Zuodong. « Three-Dimensional Model for Seabed Instability around Offshore Pipelines under Combined Wave and Current Loadings ». Thesis, Griffith University, 2020. http://hdl.handle.net/10072/391522.

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Seabed stability near offshore pipelines is one of the main concerns in engineering practice, being potentially affected by waves and ocean currents. The traditional model used to analyse soil behaviour near the pipeline assumes a two-dimensional interaction between the seabed and the marine structure. In other words, it is generally believed that the waves travel in the direction of the pipe. However, the actual marine environment is three-dimensional, with waves and currents approaching the structure from all directions. Based on a wide review of the literature, it may be claimed that the simplified 2D model no longer simulates the complex layouts of environment where offshore pipelines can be built, which should be represented as an integrated system. Therefore, the main objective of this project is to study the mechanism of soil response and liquefaction caused by waves and currents in the porous seabed near the offshore pipeline from a three-dimensional perspective. A three-dimensional numerical model is developed based on the Finite Volume Method (FVM) to analyse the instantaneous soil behaviour under the combined loads from both ocean waves and currents. In this integrated model, the hydrodynamic model is governed by the VARANS (Volume-Averaged Reynods Averaged Navier-Stokes) equation for simulating the two-phase incompressible flow motion outside and inside the porous media. The Biot’s consolidation equations are then solved for the soil responses by linking the dynamic wave pressure on the interface between the wave and seabed. The seabed behaviour is considered to be linear elastic with inversely small deformations. Overall good agreement with laboratory experimental measurements validates this newly proposed 3-D model. The numerical results reveal that the flow obliquity between the incident waves and the ocean currents has a non-negligible effect on the instantaneous pore-water pressure around the submarine pipeline, a phenomenon that cannot be observed in two dimensional numerical model. Further, a parametric study is conducted to show that the instantaneous pore-water pressure around the pipeline increases with decreasing flow obliquity; such influence can significantly increase with the increasing current velocity. Moreover, the liquefaction zone is more easily observed near the inlet of the ocean currents. By adopting the established FVM model, a numerical study on the soil response caused by waves and ocean currents near the trench structure has been conducted. The numerical results show that an offshore pipeline positioned in a trench layer is more stable than one directly laid on the seafloor. The following ocean currents can increase the liquefaction depth below the pipeline, while the opposing ocean currents can reduce the liquefaction depth near the pipeline. Moreover, the lee-wake vortex can be avoided with enough backfill thickness, which also decreases the occurrence of the onset of scour around the pipeline. Also, the nonlinear wave-current-induced seabed response around a pipe-protective cover system was investigated using the 3-D integrated model developed in OpenFOAM®. It was shown that, with sufficient quantity of stone covers and protective mattresses, the stability of the system can be maintained even with large current velocities. At this point, valuable suggestions can be drawn from the numerical results and then applied to engineering applications: (i) different backfill materials can be used to maintain the stability of a trenched pipeline with critical backfill thickness;(ii) pipelines laid directly on the surface of the seabed can be protected by a full stone cover or protective mattress under the environmental loadings from both ocean waves and currents with different directions; (iii) the protective mattress can be economically constructed over the pipeline with critical spacing to avoid an increase in the engineering budget.
Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
School of Eng & Built Env
Science, Environment, Engineering and Technology
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Livres sur le sujet "Wave loading models"

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Pressure Vessels and Piping Conference (1989 Honolulu, Hawaii). Application of modal analysis techniques to seismic and dynamic loadings : Presented at the 1989 ASME Pressure Vessels and Piping Conference--JSME co-sponsorship, Honolulu, Hawaii, July 23-27, 1989. New York, N.Y : American Society of Mechanical Engineers, 1989.

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(Editor), Lee Davison, Y. Horie (Editor) et Mohsen Shahinpoor (Editor), dir. High-Pressure Shock Compression of Solids IV : Response of Highly Porous Solids to Shock Loading (Shock Wave and High Pressure Phenomena). Springer, 1997.

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Bailey, Jason S. L. Experimentally verified fluid loading models for slender horizontal cylinders in waves. 2000.

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Chapitres de livres sur le sujet "Wave loading models"

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Murray, J. J., R. G. Standing et L. M. Mak. « Wave Loading Model Tests on a Gravity Base Structure ». Dans Advances in Underwater Technology, Ocean Science and Offshore Engineering, 161–89. Dordrecht : Springer Netherlands, 1993. http://dx.doi.org/10.1007/978-94-017-3663-3_9.

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Thomas, Stephen D. « Finite Element Model of Wave Loading on a Soil Seabed Part II : Heterogeneous Gassy Soil Conditions ». Dans Lecture Notes in Civil Engineering, 114–22. Singapore : Springer Singapore, 2022. http://dx.doi.org/10.1007/978-981-16-7735-9_10.

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Thomas, Stephen D. « Finite Element Model of Wave Loading on a Soil Seabed Part I : Multi-layered Anisotropic Gassy Soil Conditions ». Dans Lecture Notes in Civil Engineering, 105–13. Singapore : Springer Singapore, 2022. http://dx.doi.org/10.1007/978-981-16-7735-9_9.

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Kinne, Marko, Ronald Schneider et Sebastian Thöns. « Reconstructing Stress Resultants in Wind Turbine Towers Based on Strain Measurements ». Dans Lecture Notes in Mechanical Engineering, 224–35. Cham : Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-77256-7_18.

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AbstractSupport structures of offshore wind turbines are subject to cyclic stresses generated by different time-variant random loadings such as wind, waves, and currents in combination with the excitation by the rotor. In the design phase, the cyclic demand on wind turbine support structure is calculated and forecasted with semi or fully probabilistic engineering models. In some cases, additional cyclic stresses may be induced by construction deviations, unbalanced rotor masses and structural dynamic phenomena such as, for example, the Sommerfeld effect. Both, the significant uncertainties in the design and a validation of absence of unforeseen adverse dynamic phenomena necessitate the employment of measurement systems on the support structures. The quality of the measurements of the cyclic demand on the support structures depends on (a) the precision of the measurement system consisting of sensors, amplifier and data normalization and (b) algorithms for analyzing and converting data to structural health information. This paper presents the probabilistic modelling and analysis of uncertainties in strain measurements performed for the purposes of reconstructing stress resultants in wind turbine towers. It is shown how the uncertainties in the strain measurements affect the uncertainty in the individual components of the reconstructed forces and moments. The analysis identifies the components of the vector of stress resultants that can be reconstructed with sufficient precision.
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Gibson, Richard, et Chris Swan. « Extreme Environmental Loading : Long-Term Distributions of Crests, Kinematics and Loads ». Dans Ageing and Life Extension of Offshore Facilities, 169–80. ASME, 2022. http://dx.doi.org/10.1115/1.885789_ch11.

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The prediction of extreme environmental loading is critical to the assessment of the structural integrity of all fixed offshore installations. In the last ten years significant improvements have been made both in our understanding of the applied loads and our ability to model them. In particular, the importance of the following processes has been highlighted: the effects of nonlinearities beyond second-order on wave crest elevations; and both the occurrence and the effects of wave breaking on kinematics high in the water column. These effects must be included in a long-term assessment of loading. The calculation of which requires the following: a long-term model for the metocean environment; short-term models for wave processes and wave loading; and an assessment of model uncertainty. This paper presents an efficient Monte Carlo methodology through which the long - term distributions can be defined. This has been developed within the LOADS JIP. It utilises the present best practice in long-term metocean modelling, short-term models that incorporate the latest knowledge, and a rigorous assessment of epistemic uncertainties. The paper provides the results of a long-term analysis of crest elevations, kinematics, and loading for a location within the North Sea. It contrasts the findings with historical calculations and discusses the implications.
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Cronin, D. S., C. Salisbury, M. J. Worswick, R. J. Pick, K. V. Williams et D. Bourget. « Appropriate material selection for surrogate leg models subjected to blast loading ». Dans Fundamental Issues and Applications of Shock-Wave and High-Strain-Rate Phenomena, 201–8. Elsevier, 2001. http://dx.doi.org/10.1016/b978-008043896-2/50118-2.

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Kent, John, David Randell, Stephen Rose, Graham Feld et Emmanuel Fakas. « A Probabilistic Structural Reliability Assessment of Existing North Sea Platforms ». Dans Ageing and Life Extension of Offshore Facilities, 215–24. ASME, 2022. http://dx.doi.org/10.1115/1.885789_ch15.

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There are four key areas in the SRA of fixed jackets that have been impacted by recent advances in our understanding of extreme offshore wave conditions. These are: the probability distribution of crest heights in extreme seas; the occurrence of breaking waves and their associated enhanced near-surface kinematics; the calculation of wave-in-deck loading where inundation occurs; and, the probabilistic incorporation of multiple structural failure modes. The authors have applied the new approaches for platforms in the Central and Northern North Sea to assess the impact on the estimated structural reliability. The paper describes the experience of using the new methods on one of these platforms in terms of: the sensitivities of the approach to various assumptions; the simplifying assumptions that were used to make the problem more tractable; the computational complexity associated with adopting the full probabilistic approach that is inherent within the new methods; and, the overall impact of using the methods on the calculated structural reliability.
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Marshall, Shelley. « Displacement of Traditional Labour Laws ». Dans Living Wage, 51–72. Oxford University Press, 2019. http://dx.doi.org/10.1093/oso/9780198830351.003.0004.

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This chapter tracks the creation of a highly successful model for regulating the performance of head-load work in the Indian state of Maharashtra. The work normally consists of loading, unloading, carrying, shifting, weighing, tapping, and stacking goods. This is harsh physical labour, often undertaken in extreme heat. Following a concerted campaign in the 1960s, a tripartite regulatory system was introduced to overcome many of the problems historically faced by the mathadi workers, such as a lack of job security and access to social security. The study is a fruitful site of regulatory learning because India’s legislatures have been more active in regulating informal work, particularly in the domain of providing social security, than perhaps anywhere else in the world. The Indian state has used various mechanism to do this, the best-documented of which are the Welfare Boards of Kerala. In contrast to the Welfare Boards, there is very little written about the Mathadi Boards of Maharashtra, which have a broader regulatory reach and have arguably been far more successful.
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Trajkovski, Jovan. « Validation of a Numerical Model of Detonation of Buried Charges in Soil ». Dans Monitoring and Protection of Critical Infrastructure by Unmanned Systems. IOS Press, 2023. http://dx.doi.org/10.3233/nicsp230014.

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Critical infrastructure, military or civil equipment, buildings, and Light Armored Vehicles (LAV) can be exposed to blast and ballistic loading during their lifetime. Such loads can cause large deformations and stresses within a very short period of time. For that purpose, it is necessary to examine and improve their response to these high-intensity and short-term loads. The analytical approaches are complex, the performance of large-scale experimental tests is extremely expensive since it involves a number of experts, special legal permits, and safety requirements which makes numerical analysis the most valuable examination tool. On the other side, a precise numerical analysis requires precise material properties, to describe the material behavior under various conditions. Before analyzing the response of structures under blast loads, the numerical model should be carefully validated first. This paper presents the validation results of the numerical model of small-scale explosion tests of charges laid on the ground or buried in the soil. The numerical results for time of arrival, maximum pressure, and specific impulse are compared with the experimental results showing a good correlation. The influence of depth of burial (DoB) on blast wave development and soil ejecta formation and loading parameters is investigated in detail.
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Tao, Yun, Rosti Lemdiasov, Arun Venkatasubramanian et Marshal Wong. « Segmented Coil Design Powering the Next Generation of High-efficiency Robust Micro-implants ». Dans Wireless Power Transfer - Perspectives and Application [Working Title]. IntechOpen, 2022. http://dx.doi.org/10.5772/intechopen.105789.

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The next generation of Micro Active Implantable Medical Devices (M-AIMD) are small (< 1 cc), wireless, as well as battery-less. They are located in different parts of the body ranging from brain computer interface electrode arrays (e.g., Blackrock Neurotech Utah Array) to multi-chamber cardiac pacemakers (e.g., Abbott dual chamber Nanostim device). These devices require efficient charging and powering solutions that are very challenging to design. Such solutions require the careful balancing of multiple design parameters such as size, separation distance, orientation, and regulatory limits for emission and tissue safety. In this article, we introduce unique optimisation metrics for designing efficient transmit and receive coils for near-field magnetics-based charging solutions. We elaborate on how the metrics need to be altered depending on the regulatory limits. We discuss the impact of body tissue loading on transmit and receive coil performance using circuit analysis. We introduce a novel “segmented” transmit coil arrangement. We discuss the physics of segmentation, and we build a full wave simulation model, with practical design procedure, which is verified with measurements. Finally, we compare the near fields with and without tissue loading to show that segmented coils offer significant improvement to the performance and robustness of a wireless power transfer system.
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Actes de conférences sur le sujet "Wave loading models"

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Zaman, M. H., et R. E. Baddour. « Wave-Current Loading on a Vertical Slender Cylinder by Two Different Numerical Models ». Dans 25th International Conference on Offshore Mechanics and Arctic Engineering. ASMEDC, 2006. http://dx.doi.org/10.1115/omae2006-92135.

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The study of the effects resulting from the interaction of a combined wave-current field with any ocean structure is important for the design and performance evaluation of that structure. The prudent computation of forces exerted by waves and currents is an essential task in the study of the stability of an offshore structure. A study on the loading of an oblique wave and a current field on a fixed vertical slender cylinder in a 3D flow frame is illustrated in Zaman and Baddour (2004). The three dimensional expressions describing the characteristics of the combined wave-current field in terms of mass, momentum and energy flux conservation equations are formulated. The parameters before the interaction of the oblique wave-free uniform current and current-free wave are used to formulate the kinematics of the flow field. These expressions are also employed to formulate and calculate the loads imparted by the wave-current fluid flow on a bottom mounted slender vertical cylinder. In this work a 2D version of the above 3D model called here Model-I has been used for the numerical computations presented in this paper. The second model denoted model-II in the present paper is based on Euler equations. This model is formulated through the vertical integration of the continuity equation and the equations of motions, Zaman et al (1997). A semi-implicit numerical technique is employed for the numerical solution. In the present paper comparisons are made between the results obtained from the 2D version of the above models in finite depth. Both models are then compared with some relevant experimental data. Morison et al equation (1950) is deployed for the load computations in all cases.
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Zaman, M. H., et R. E. Baddour. « Loading on a Fixed Vertical Slender Cylinder in an Oblique Wave-Current Field ». Dans ASME 2004 23rd International Conference on Offshore Mechanics and Arctic Engineering. ASMEDC, 2004. http://dx.doi.org/10.1115/omae2004-51062.

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A study of the loading of an oblique wave-current field on a slender cylinder in a 3D flow frame is reported in this paper. The three dimensional expressions describing the characteristics of the combined wave-current field in terms of mass, momentum and energy flux conservation equations are formulated. The parameters before the interaction of the oblique wave-free uniform current and current-free waves are used to formulate the kinematics of the flow field. These expressions are also employed to formulate and calculate the loads imparted by the wave-current fluid flow on a bottom mounted slender vertical cylinder. A comparison of the obtained results due to the present model to those obtained using three other models being used in the offshore industry is shown for a range of the normalized current parameters. One of these three models is proposed by the American Petroleum Institute (API), which is based on a superposition principle. Morison et al equation is deployed for the load computations in all cases. Comparisons among the obtained results in a normalized manner are shown and discussed.
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Scharnke, Jule, Rene Lindeboom et Bulent Duz. « Wave-in-Deck Impact Loads in Relation With Wave Kinematics ». Dans ASME 2017 36th International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/omae2017-61406.

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Breaking waves have been studied for many decades and are still of interest as these waves contribute significantly to the dynamics and loading of offshore structures. In current MARIN research this awareness has led to the setup of an experiment to determine the kinematics of breaking waves using Particle Image Velocimetry (PIV). The purpose of the measurement campaign is to determine the evolution of the kinematics of breaking focussed waves. In addition to the PIV measurements in waves, small scale wave-in-deck impact load measurements on a fixed deck box were carried out in the same wave conditions. To investigate the link between wave kinematics and wave-in-deck impact loads, simplified loading models for estimating horizontal deck impact loads were applied and compared to the measured impact loads. In this paper, the comparison of the model test data to estimated loads is presented.
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El Safti, Hisham, Lisham Bonakdar et Hocine Oumeraci. « A Hybrid 2D-3D CFD Model System for Offshore Pile Groups Subject to Wave Loading ». Dans ASME 2014 33rd International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/omae2014-23636.

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A hybrid 2D-3D CFD model is developed for studying water wave loads on a slender pile in a pile group. In the hybrid model approach, a one-way link is established between a model for the far-field and another for studying the fluid-structure interaction in the near field. In the far-field a 2D incompressible Navier-Stokes multiphase solver is considered for the proper reproduction of phase-focused (freak) waves produced in physical experiments. The near-field model is a multiphase 3D CFD model that utilizes compressible Navier-Stokes equations to enhance the simulation of entrapped air compressibility effects during breaking wave impact on structures. Both models use the Volume-Of-Fluid (VOF) method to capture the air-water interface and alternatively a RANS or LES turbulence model. An overlap zone is introduced to both models, in which fluid kinematics and surface elevation are sampled from the far-field model and introduced via a relaxation function to the overlap zone in the near-field model. In the 3D model, the use of a relaxation approach provides absorption for reflected waves from the structure. Further, a procedure is outlined to achieve/enhance the 3D model convergence. This is necessary in case of the development of artificial high velocities at water-air interface at the end of a short overlap (relaxation) zone for wave inlet (or near the boundary if only a wave inlet boundary condition is considered). The model system is developed using the OpenFOAM® framework. The overlap zone is implemented as an extension to the waves2Foam [1] toolbox.
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Najafian, G. « Comparison of three probability models for offshore structural response due to Morison wave loading ». Dans FLUID STRUCTURE INTERACTION/MOVING BOUNDARIES 2007. Southampton, UK : WIT Press, 2007. http://dx.doi.org/10.2495/fsi070041.

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Hennig, Janou, Jule Scharnke, Chris Swan, Øistein Hagen, Kevin Ewans, Peter Tromans et George Forristall. « Effect of Short-Crestedness on Extreme Wave Impact : A Summary of Findings From the Joint Industry Project “ShorTCresT” ». Dans ASME 2015 34th International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2015. http://dx.doi.org/10.1115/omae2015-41167.

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Long-crested waves are typically used in the design of offshore structures. However, the corresponding statistics, kinematics and loading are significantly different in short-crested waves and up to date, there is no state-of-the-art methodology to apply short-crested models instead. The objective of the “ShortCresT” Joint Industry Project was to take into account short-crestedness in the design of offshore structures against extreme waves based on a good description of their spectral characteristics, statistics, kinematics, breaking and loading and to deliver (empirical) design recommendations and methods. This paper gives an overview of the findings of ShorTCresT regarding wave crest and height distributions, a comparison of basin and field data, the role of wave breaking, the most realistic directional model, hindcast models as well as the related platform loading.
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Laksari, Kaveh, Mehdi Shafieian, Kurosh Darvish et Keyanoush Sadeghipour. « Shock Wave Propagation as a Mechanism of Injury in Nonlinear Viscoelastic Soft Tissues ». Dans ASME 2011 International Mechanical Engineering Congress and Exposition. ASMEDC, 2011. http://dx.doi.org/10.1115/imece2011-64717.

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This study investigates the propagation of shock waves and self-preserving waves in soft tissues such as brain as a mechanism of injury in high rate loading conditions as seen in blast-induced neurotrauma (BINT). The derived mathematical models indicate that whereas linear viscoelastic models predict only decaying waves, instances of such phenomena as shock can be achieved in nonlinear media. In this study, a nonlinear viscoelastic material model for brain tissue was developed in compression. Furthermore, nonlinear viscoelastic wave propagation in brain tissue was studied and a criterion for the development of shock waves was formulated. It was shown that discontinuities in the acceleration that happen in blast loading conditions may evolve to shock waves, resulting in large discontinuities in strain and stress at the wave front leading to tissue injuries.
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Yu, H., et N. Srivastava. « Dynamic Response of a Floating Cylinder Subjected to Coupled Wave and Wind Loading ». Dans ASME 2012 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/imece2012-87926.

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The broad objective of the research presented herein is to analyze dynamical interactions in offshore structures under combined wind and wave loads for enhanced power delivery and reliability of hybrid wind-wave generation systems. As an offshore structure representative, a model for an inclined floating cylinder at finite depth is developed employing linear wave theory coupled with wind-induced effects. Although detailed wave models have often been incorporated while studying the dynamics of such cylinders, wind-induced effects have been mostly modeled as an axial drag term that affects the drift of the structure along the wind direction. In this article, the effects of not only wind-induced drag, but also lift and oscillations on the structure (i.e. the floating inclined cylinder) are studied. Further, the effects of vortex shedding are considered. Cross-flow principle is used to calculate the wind loads on the cylinder. Assuming small wave steepness and a large radius of cylinder (in comparison to the wavelength), linear wave diffraction and radiation theory coupled with wind-induced effects is employed to analyze the dynamic response of the inclined floating cylinder. Numerical results on the dynamic response of an inclined floating cylinder subjected to coupled wind-wave loading system are presented and discussed while highlighting the increasing relevance of such modeling strategies for hybrid wind-wave power generation systems and their control.
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Saladin, Tara, Young W. Kwon et Joseph T. Klamo. « Comparison of Different Modeling Techniques for Solid-Fluid Interface for Wave Loading ». Dans ASME 2021 40th International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2021. http://dx.doi.org/10.1115/omae2021-62083.

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Abstract Computational fluid dynamics (CFD) has been used to estimate the wave loading applied to a fully submerged body near the surface. The Navier-Stokes equations were used for the present study. In terms of modeling the fluid-solid interface, two different techniques are available in ANSYS CFX. One is the Rigid Body Method (RBM) and the other is the Immersed Solid Method (ISM). This paper compares the two modeling techniques in terms of accuracy and modeling flexibility. For this study, a CFD model of the NPS tow tank with wave generation and a submerged body was created to investigate different methods of solid body modeling. A comparison of the RBM and ISM was performed modeling a submerged rectangular body at different depths. The models produced similar results when the body was lower beneath the wave surface with limited fluid-solid interaction. As the amount of fluid-solid interaction increased, the RBM showed increased amounts of wave energy dissipation as compared to the ISM. This disruption of the wave energy resulted in the RBM showing smaller body forces and moments when compared to the ISM solid model. The increased wave energy dissipation in the RBM is likely caused by the different mechanism for modeling body-solid interaction. The numerical results were also compared to the experimental data.
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Spencer, Don, Stergios Liapis, Yiannis Constantinides, Mohammed Islam et Zachary Edwards. « Full-Scale Measurements of Wave and Current Loads on Splitter Fairings ». Dans ASME 2014 33rd International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/omae2014-24516.

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This paper presents measurements of the mechanical loads that splitter fairings on vertical and inclined risers will experience while in the wave zone or due to current drag. A 21″ pipe was utilized for the measurements, which corresponds to prototype size for a production riser and a 1:2.5 scaled model for a 54″ drilling riser. The program had three objectives, (a) to determine the nature of wave and current loading on a riser segment that was fitted with a fairing to provide sufficient internal strength and stiffening; (b) to determine the wave and current loading on the fairing connection system to assist in designing reliable latching systems, and (c) to investigate if the measured loading on the fairings from forced oscillation experiments can be used to simulate loading resulting from wave motion. Of primary interest was the effect of wave loading on the fairings in prototype or near prototype conditions. One significant impediment to conducting such experiments in a model wave basin was the very limited ability of the basin to generate full scale wave in terms of period or height. However the horizontal component of the oscillatory wave velocity can be simulated by oscillating the fairings at prototype wave periods and amplitudes to obtain the same relative flow condition. One of the fundamental questions that remained prior to the research was whether the novel forced oscillation technique could actually replicate the real world wave induced loads and some experiments were directed at confirming this. While exploratory in nature, these forced oscillation experiments demonstrated that the test apparatus and methodology were able to replicate the corresponding measurements from the wave experiments, thus providing reliable data to assist in predicting hydrodynamic loading on fairings due to current, forced oscillatory motion, and waves. The basin carriage was successfully used to force the fairings in a prescribed oscillatory motion. The analysis of the measurements of the forced oscillation experiments showed that the inertial force correlated well and was linearly proportional to acceleration while the viscous force was a linear function of velocity. It was demonstrated that the forced oscillation experiments could provide reasonably good estimates of the global loading resulting from wave action. This implies that the experimental technique of replacing wave motion with forced oscillation can be used for design. As a result, prototype or near prototype scale models of fairings can be tested in wave conditions well beyond the capability of model basins. While the global loads due to waves could be predicted from the forced experiments it appeared the latching load were about 70% higher while in waves relative to those recorded during the forced oscillation experiments. This discrepancy could be attributed to free surface effects.
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