We present a numerical study of the impact of a two-dimensional plunging wave on a rigid vertical wall in the context of potential flow. The plunging wave impinging the wall is generated using a mixed-Eulerian-Lagrangian (MEL) boundary-integral scheme. The initial stage of the impact is characterized by an oblique impact of a liquid wedge on the wall and is solved using a similarity solution. Following the initial impact, the MEL simulation is continued to capture the transient impact process. The effect of an air cushion trapped between the plunger and the wall is considered. In addition to details such as temporal evolutions and surface profiles, the main interests are the maximum impact pressure on the wall and its rise time. To arrive at appropriate scaling laws for these, simulations are performed and correlations are explored for a broad range of local plunging wave kinematic and geometric parameters. To assess the present results, direct comparisons are made with the experiment of Chan & Melville (1988). Reasonable quantitative agreement is obtained and likely sources for discrepancies are identified and discussed.

Simulation of plunging wave impact on a vertical wall

In certain passive, future boiling water reactor concepts, during emergency cooling conditions, mixtures of steam and nitrogen are blown into a pool of water via a downward-facing open pipe; at its end, large gas bubbles form, break up, and rise in the water. We have developed a computer simulation program for the hydrodynamics of the process using an isothermal piecewise linear interface construction-volume of fluid method and carried out an experiment with flow rates up to 50 l/s into a tank of 1 m3 volume. Bubble frequencies and volumes can be predicted fairly well for the case of air injection. The experiments show that most of the condensation takes place before the bubble detaches from the pipe exit. The phenomena depend mainly on the volumetric flow rate of the gas and on a parameter measuring the shrinkage due to condensation. The rates of condensation were estimated to be very high.

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Numerical and Experimental Study of Large Steam-Air Bubbles Injected in a Water Pool

https://icce-ojs-tamu.tdl.org/icce/index.php/icce/article/download/4766/4447

Wave impact forces on mixed breakwaters

A 3-D time-domain numerical coupled model for nonlinear waves acting on a ship in a harbor has been developed in the present study. The whole domain is divided into the inner domain and the outer domain. The inner domain is the area around the ship, where the flow is expressed by the Laplace equation and numerically solved by the finite element method. The other area is the outer domain, where the flow is described by the higher-order Boussinesq equations and numerically solved by the finite difference method. The matching conditions on the interfaces between the inner domain and the outer domain, the procedure of coupled solution, the length of common domain and the mesh generation in the inner domain are discussed in detail. The other coupled model with the flow in the inner domain governed by the simplified linear Euler equations and relevant physical experiment are adopted to validate the present coupled model, and it is shown that the numerical results of the present model agree with the experimental data, so the present model can be used for the study on the effect of nonlinear waves acting on a fixed ship in a large area and provide a reference for the time-domain simulation of nonlinear wave forces on an arbitrary object in a large harbor and the 3-D district computation in the future.

A three-dimensional coupled numerical model of nonlinear waves in a harbor

In this paper, an improved volume of fluid (VOF) technique has been used to test numerical simulation of breaking waves against a vertical wall seated on a structural foundation. Laitone's second order solitary wave theory is used as the initial conditions. When no foundation is present, the run up of a solitary wave on a vertical wall for a range of H/d agrees well with the experimental data. The phenomena of wave breaking, such as wave steepening, overturning and formulation of bores, have been successfully simulated by an improved VOF method. Very high intensity shock pressure and wave impact force on the vertical wall are also obtained.

T C Su

Papers

Numerical Simulation Of Breaking Waves Against Vertical Wall