Inner harbour wave agitation using boussinesq wave model (original) (raw)
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Assessment of a Boussinesq wave model for the design of a harbour
1995
Over the years, a number of numerical models have been implemented with the original or equivalent forms of the Boussinesq wave equations. Their veri cations however, have been carried out mainly for one dimensional conditions and with experiments of speci c wave phenomena. Two dimensional model veri cations of real wourld problems are rare and usually done for simple conditions. In this paper a Boussinesq wave model under development at the Institute of Fluid Mechanics in Hannover was veri ed with physical model measurements carried out for a complex harbour entrance in northern Germany with shallow and deep water regions and steep bottom slopes. The domain of interest was described by nite di erence grids with up to 500,000 nodes. The results of the simulations showed that the model is capable of capturing the wave transformation phenomena and suggest that applications of Boussinesq wave models for the design of harbours are within reach. In the simulations, the discrepancies between computed and measured wave heights are more signi cant in locations close to the highly irregular boundaries near the marina and ferry terminal. The smoothing approach applied to damp out the numerical noise in that vicinity, the grid resolution which cannot properly account for all the irregularities and the uncertainties regarding the re ection coe cients are the reasons for the lack of agreement.
The ambitious Sagarmala project initiated by Govt of India (GOI) envisages development of water borne transport facilities owing to its affordability compared to other modes of transport system. As a part of Sagarmala project developing small tourist harbours at the inlets along the East coast of India is under consideration. East coast of India has steep sea bed slope, severe wave climate, heavy littoral drift and rivers debouch into Bay of Bengal with high source of sediment. Mouths may choke up due to sediment. Hence to evolve the layout of the harbour, comprehensive studies of wave transformation and tranquility, hydrodynamics, sedimentation are required. The present paper proposes a method to study effects of wave induced processes on the shore, in the inlet and mouth. Comprehensive study to assess the feasibility of developing a tourist harbour in the inlet on the east coast of India is reported. The mathematical model study consisted of transforming the offshore wave climate to obtain the near shore wave condition, estimating radiation stresses and longshore sediment transport. The method is explained with a case study of typical harbour on the east coast of India. The wave hydrodynamics studies were carried for existing condition and with two layouts, PRO1 layout with the channel (5.0 m depth) and turning circle (5.5 m depth) and PRO2 layout is modified from PRO1 by adding, sand pits (6.5 m depth) adjacent to the inlet on south and north sides. MIKE 21-SW model was used for the wave transformation studies with 69 x 70km area. Deepwater wave data was analysed to obtain the input wave parameters for the transformation studies. The littoral drift was calculated at three locations with different shoreline orientation near the inlet, with LITPACK model.
SIMULATION OF LONG WAVE AGITATION IN PORTS AND HARBOURS USING A TIME-DOMAIN BOUSSINESQ MODEL
2000
A time-domain Boussinesq type model including wave breaking is used to simulate long wave agitation in two different harbour configurations. The substantial seiche in the exposed Torsminde fishery harbour, Denmark is modelled, and the results are discussed and evaluated against measurements. The second case is a model application to modelling seiche in the Port of Long Beach, CA where low-frequency
Numerical analysis of wave hazards in a harbor
Science China Earth Sciences, 2012
Resonance may occur when the periods of incoming waves are close to the eigen-periods of harbor basin. The amplified waves by resonance in harbor will induce serious wave hazards to harbor structures and vehicles in it. Through traditional theoretical approaches, the eigen-periods of harbor basin with regular shapes can be obtained. In our study, we proposed a numerical model to simulate the behavior characteristics of the harbor waves. A finite difference numerical model based on the shallow water equations (SWE) is developed to simulate incoming tsunami and tidal waves. By analyzing the time series data of water surface wave amplitude variations at selected synthetic observation locations, we estimate the wave height and arrival time in coastal area. Furthermore, we use frequency spectrum analysis to investigate the natural frequencies from the data recorded at the synthetic observation stations.
Spectral Density Analysis for Wave Characteristics in Pohang New Harbor
Pure and Applied Geophysics, 2013
The Pohang New Harbor (PNH), located at the Yongil bay in the northeastern part of Pohang city, South Korea, has experienced extreme wave hazards of about 3.0-5.0 m in elevation due to the seasonal swell from the far ocean. In this paper, both analytical and numerical studies are performed to investigate the wave-induced oscillations in an arbitrary shaped harbor with corner point consideration. By taking the consideration of the actual topography and bathymetry data, the boundary of PNH is constructed. Our theoretical model is based on the assumptions of inviscid, irrotational fluid, infinitesimal wave amplitude, and finally, the Helmholtz equation and its Weber's solution. The numerical simulations are conducted to analyze the spectral density of the standing waves in PNH at eight respective synthetic record points. The simulation results are validated with real-time measurement data, which is obtained by wave heights and tide gauges at the specified record points within and outside the PNH. To improve the harbor's design, a tactic such as building the breakwater at the entrance of the harbor is implemented and then spectral density is estimated in the modified geometry of the PNH. The consequential effects are proposed at the same time, suggesting the feasibility of the improvement measures.
An analytical investigation of wave-induced oscillations of water in a rectangular harbour
Indian Journal of Engineering and Materials Sciences, 1997
The wave-induced oscillations of water in a rectangular harbour have been studied on the basis of the linear potential wave theory. Mathematical expressions for the problem of oscillations of water and the amplification factor for the rectangular harbour have been derived. Based on these expressions, a number of computer programmes have been developed in FORTRAN 77 and executed on the IBM 4332 LO2 System at the Computer Centre of Bangladesh University of Engineering and Technology. The computational results have been plotted and then physically interpreted with a view to predicting the hydrodynamic response characteristics of the rectangular harbour.
Numerical Modeling of Wave Penetration in Ostend Harbour
Coastal Engineering Proceedings, 2011
The initial Ostend harbour entrance at the North Sea coast of Belgium is being modified and extended with two new rubble-mound breakwaters. Through an integrated study of the wave penetration in Ostend harbour, the waves are being acquired by prototype measurements and physical and numerical modelling is carried out. Two numerical models are used. SimWave is a numerical model based on Nwogu’s extended Boussinesq equations. The second numerical model is MILDwave, a mild-slope wave propagation model based on the equations of Radder and Dingemans. The present study concentrates on applications of the numerical models, throughout the different design stages and construction phases of the new breakwaters.
Wave modelling at the entrance of ports
Ocean Engineering, 2011
The objective of the present work was to develop and validate a flexible wave prediction system able to provide information about the wave conditions at the entrance of ports. Although the method is general, the present application addresses the major Portuguese ports, namely Leixões and Sines that are located in the northern and in the central part, respectively, of the Portuguese continental coast. A multilevel system for modelling the wave transformation (SWAN based) is implemented in the entire west Iberian nearshore and validated with buoy data. The ocean forcing is provided by WAM model simulations in an implementation over the entire North Atlantic basin. Both hindcast, nowcast and forecast schemes are evaluated and discussed. Focusing then on the two target areas, an analysis of some coastal processes such as diffraction and triad wave-wave interactions, as they are reflected in the simulations based on spectral models, is also performed. Finally, some average energetic and storm scenarios were also considered for the two harbours.
Simulation of wave action on a moored container carrier inside Sines’ Harbour
Maritime Technology and Engineering, 2014
The integrated numerical tool SWAMS (Simulation of Wave Action on Moored Ships) is used to simulate the behavior of a moored container carrier inside Sines' Harbour. Wave, wind, currents, floating ship and moorings interaction is discussed. Several case scenarios are compared differing in the layout of the harbour and wind and wave conditions. The several harbour layouts correspond to proposed alternatives for the future expansion of Sines' terminal XXI that include the extension of the East breakwater and of the quay. Additionally, the influence of wind on the behavior of the ship moored and the introduction of pre tensioning the mooring lines was analyzed. Hydrodynamic forces acting on the ship are determined using a modified version of the WAMIT model. This modified model utilizes the Haskind relations and the non-linear wave field inside the harbour obtained with finite element numerical model, BOUSS-WMH (Boussinesq Wave Model for Harbors) to get the wave forces on the ship. The time series of the moored ship motions and forces on moorings are obtained using BAS solver.