Hydrodynamic force and wave run-up due to diffraction of ocean water waves by a surface-piercing bottom-mounted compound partial-porous cylinder

2021 ◽  
Vol 53 (1) ◽  
pp. 015508
Author(s):  
Abhijit Sarkar ◽  
Swaroop Nandan Bora
2020 ◽  
Vol 2020 (1) ◽  
Author(s):  
Marin Marin ◽  
M. M. Bhatti

AbstractThe present study deals with the head-on collision process between capillary–gravity solitary waves in a finite channel. The present mathematical modeling is based on Nwogu’s Boussinesq model. This model is suitable for both shallow and deep water waves. We have considered the surface tension effects. To examine the asymptotic behavior, we employed the Poincaré–Lighthill–Kuo method. The resulting series solutions are given up to third-order approximation. The physical features are discussed for wave speed, head-on collision profile, maximum run-up, distortion profile, the velocity at the bottom, and phase shift profile, etc. A comparison is also given as a particular case in our study. According to the results, it is noticed that the free parameter and the surface tension tend to decline the solitary-wave profile significantly. However, the maximum run-up amplitude was affected in great measure due to the surface tension and the free parameter.


2021 ◽  
Vol 9 (7) ◽  
pp. 784
Author(s):  
Arnida Lailatul Latifah ◽  
Durra Handri ◽  
Ayu Shabrina ◽  
Henokh Hariyanto ◽  
E. van Groesen

This paper shows simulations of high waves over different bathymetries to collect statistical information, particularly kurtosis and crest exceedance, that quantifies the occurrence of exceptionally extreme waves. This knowledge is especially pertinent for the design and operation of marine structures, safe ship trafficking, and mooring strategies for ships near the coast. Taking advantage of the flexibility to perform numerical simulations with HAWASSI software, with the aim of investigating the physical and statistical properties for these cases, this paper investigates the change in wave statistics related to changes in depth, breaking and differences between long- and short-crested waves. Three different types of bathymetry are considered: run-up to the coast with slope 1/20, waves over a shoal, and deep open-water waves. Simulations show good agreement in the examined cases compared with the available experimental data and simulations. Then predictive simulations for cases with a higher significant wave height illustrate the changes that may occur during storm events.


Author(s):  
K. A. Belibassakis ◽  
G. A. Athanassoulis

A coupled-mode model is developed and applied to the transformation and run-up of dispersive water waves on plane beaches. The present work is based on the consistent coupled-mode theory for the propagation of water waves in variable bathymetry regions, developed by Athanassoulis & Belibassakis (1999) and extended to 3D by Belibassakis et al (2001), which is suitably modified to apply to a uniform plane beach. The key feature of the coupled-mode theory is a complete modal-type expansion of the wave potential, containing both propagating and evanescent modes, being able to consistently satisfy the Neumann boundary condition on the sloping bottom. Thus, the present approach extends previous works based on the modified mild-slope equation in conjunction with analytical solution of the linearised shallow water equations, see, e.g., Massel & Pelinovsky (2001). Numerical results concerning non-breaking waves on plane beaches are presented and compared with exact analytical solutions; see, e.g., Wehausen & Laitone (1960, Sec. 18). Also, numerical results are presented concerning the run-up of non-breaking solitary waves on plane beaches and compared with the ones obtained by the solution of the shallow-water wave equations, Synolakis (1987), Li & Raichlen (2002), and experimental data, Synolakis (1987).


Author(s):  
Pavel Evgenievich Burakovskiy

One of the most dangerous situations for seagoing ships is wave run-up in a head sea. In such a case, significant hydrodynamic forces appear resulting in stability loss or ship hull damage. The paper presents structural solutions that contribute towards navigation safety by means of decreasing probability of wave run-up of the ship bow in a head sea. A design has been developed of a ship stabilizer in the form of hinge-mounted stabilizing wings which deflect from the hull when the bow submerges in water and then cling to it when it emerges. The paper presents a new design of the bulwark with rotating sections able to rotate in the direction from the deck to the board. These designs can reduce dipping in a wave and reduce hydrodynamic impact on the bow. Apart from this, a hull structure has been proposed with a detachable bow to prevent capsizing of a ship. If the hydrodynamic force reaches a critical value, destruction of a permanent joint will happen in the proposed design, resulting in the situation when leak-proof aft and bow parts detach and remain afloat, which will allow the crew to evacuate. The proposed designs will increase navigation safety in storm conditions.


1974 ◽  
Vol 1 (14) ◽  
pp. 26 ◽  
Author(s):  
J.A. Battjes

This paper deals with the following aspects of periodic water waves breaking on a plane slope breaking criterion, breaker type, phase difference across the surfzone, breaker height-to-depth ratio, run-up and set-up, and reflection. It is shown that these are approximately governed by a single similarity parameter only, embodying both the effects of slope angle and incident wave steepness. Various physical interpretations of this similarity parameter are given, while its role is discussed m general terms from the viewpoint of model prototype similarity.


Volume 1 ◽  
2004 ◽  
Author(s):  
Remus Ciobotaru ◽  
Razvan Bidoae ◽  
Peter E. Raad

The generation of single large waves by a forced motion of solid bodies in a three-dimensional, rectangular channel is investigated. The moving bodies can have simple (idealized) or more complex shapes. The shape and characteristics of the imposed motion are shown to affect the dynamics of the resulting single wave. Waves generated by three different types of landslides are compared by recording the hydrodynamic force and run-up height on a solid plane wall. The three types of landslides investigated are: (i) bottom movement (submarine landslide), (ii) falling mass (partially submerged landslide), and (iii) sliding mass (subaerial landslide).


Author(s):  
John T. Imamura ◽  
Alaa Mansour

This paper proposes a design concept in the area of overtopping ocean wave energy devices. Current models of overtopping devices are limited to locations which experience large wave activity. The high energy associated with large waves enables the ocean water waves to overtop the device ramp into the collection reservoir which discharges through a power generating turbine. The ramp height is necessarily large to establish a sufficient collection reservoir head. The proposed design concept can utilize small waves by implementing a gearing system which can transfer water to the collection reservoir. This allows for greater access to the wave energy resource at more locations than currently possible. A simplified model of this design concept is presented and applied to varying wave conditions off the coast of California.


2020 ◽  
Author(s):  
Gayaz Khakimzyanov ◽  
Denys Dutykh ◽  
Dimitrios Mitsotakis ◽  
Nina Yu Shokina

In the present article, we describe a few simple and efficient finite volume type schemes on moving grids in one spatial dimension combined with an appropriate predictor–corrector method to achieve higher resolutions. The underlying finite volume scheme is conservative, and it is accurate up to the second order in space. The main novelty consists in the motion of the grid. This new dynamic aspect can be used to resolve better the areas with large solution gradients or any other special features. No interpolation procedure is employed; thus, unnecessary solution smearing is avoided, and therefore, our method enjoys excellent conservation properties. The resulting grid is completely redistributed according to the choice of the so-called monitor function. Several more or less universal choices of the monitor function are provided. Finally, the performance of the proposed algorithm is illustrated on several examples stemming from the simple linear advection to the simulation of complex shallow water waves. The exact well-balanced property is proven. We believe that the techniques described in our paper can be beneficially used to model tsunami wave propagation and run-up.


2007 ◽  
Vol 14 (4) ◽  
pp. 385-393 ◽  
Author(s):  
K. R. Bryan ◽  
G. Coco

Abstract. Natural geophysical timeseries bear the signature of a number of complex, possibly inseparable, and generally unknown combination of linear, stable non-linear and chaotic processes. Quantifying the relative contribution of, in particular, the non-linear components will allow improved modelling and prediction of natural systems, or at least define some limitations on predictability. However, difficulties arise; for example, in cases where the series are naturally cyclic (e.g. water waves), it is most unclear how this cyclic behaviour impacts on the techniques commonly used to detect the nonlinear behaviour in other fields. Here a non-linear autoregressive forecasting technique which has had success in demonstrating nonlinearity in non-cyclical geophysical timeseries, is applied to a timeseries generated by videoing the waterline on a natural beach (run-up), which has some irregular oscillatory behaviour that is in part induced by the incoming wave field. In such cases, the deterministic shape of each run-up cycle has a strong influence on forecasting results, causing questionable results at small (within a cycle) prediction distances. However, the technique can clearly differentiate between random surrogate series and natural timeseries at larger prediction distances (greater than one cycle). Therefore it was possible to clearly identify nonlinearity in the relationship between observed run-up cycles in that a local autoregressive model was more adept at predicting run-up cycles than a global one. Results suggest that despite forcing from waves impacting on the beach, each run-up cycle evolves somewhat independently, depending on a non-linear interaction with previous run-up cycles. More generally, a key outcome of the study is that oscillatory data provide a similar challenge to differentiating chaotic signals from correlated noise in that the deterministic shape causes an additional source of autocorrelation which in turn influences the predictability at small forecasting distances.


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