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Added mass
About: Added mass is a research topic. Over the lifetime, 2849 publications have been published within this topic receiving 47899 citations.
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TL;DR: In this paper, the authors investigated how the added mass, the hydrodynamic damping and the drag coefficient of a Wave Energy Converter (WEC) can be calculated using DualSPHysics, a software application that applies the Smoothed Particle Hydrodynamics (SPH) method.
Abstract: In this paper, we investigated how the added mass, the hydrodynamic damping and the drag coefficient of a Wave Energy Converter (WEC) can be calculated using DualSPHysics DualSPHysics is a software application that applies the Smoothed Particle Hydrodynamics (SPH) method, a Lagrangian meshless method used in a growing range of applications within the field of Computational Fluid Dynamics (CFD) Furthermore, the effect of the drag force on the WEC’s motion and average absorbed power is analyzed Particularly under controlled conditions and in the resonance region, the drag force becomes significant and can greatly reduce the average absorbed power of a heaving point absorber Once the drag coefficient has been determined, it is used in a modified equation of motion in the frequency domain, taking into account the effect of the drag force Three different methods were compared for the calculation of the average absorbed power: linear potential flow theory, linear potential flow theory modified to take the drag force into account and DualSPHysics This comparison showed the considerable effect of the drag force in the resonance region Calculations of the drag coefficient were carried out for three point absorber WECs: one spherical WEC and two cylindrical WECs Simulations in regular waves were performed for one cylindrical WEC with two different power take-off (PTO) systems: a linear damping and a Coulomb damping PTO system The Coulomb damping PTO system was added in the numerical coupling between DualSPHysics and Project Chrono Furthermore, we considered the optimal PTO system damping coefficient taking the effect of the drag force into account
17 citations
TL;DR: In this paper, the translational motion and oscillations of the radius of a spherical gas bubble in a spherical flask filled with a weakly compressible liquid are considered when there is forced radial perturbation of the flask wall.
17 citations
TL;DR: In this article, a potential theory is presented for the problem of two moving circular cylinders, with possibly different radii, large motions, immersed in an perfect stagnant fluid, and the fluid force is the superposition of an added mass term, related to the time variations of the potential, and a quadratic term related to its spatial variations.
17 citations
TL;DR: In this paper, the dispersion equation for a fluid-loaded sandwich plate is derived and the convergence rate of an approximate solution based on the modal composition of the Green matrix is estimated.
17 citations
01 Jan 2010
TL;DR: In this article, the effect of sloshing on the ship motion in oblique seas is quantified using a linear diffraction method and a time-domain simulation of the ship motions.
Abstract: Ships with partially filled liquid tanks, such as LNG carriers or FPSOs, are sensitive to sloshing in case they are exposed to waves. The effect of sloshing can have a pronounced effect on the ship motions, in particular roll in oblique seas. In this paper several methods are described which can be used to quantify this effect. The first is a linear diffraction method in which the effect of the liquid in the tank is modeled as a solid inertia of the fluid mass, an added mass and damping of the sloshing fluid and a hydrostatic free-surface correction to the GM. The response is easily computed in the frequency domain. The second is a time domain method in which the sloshing liquid in the tank is modeled with the CFD code ComFLOW. The forces exerted by the liquid on the tank walls is included in a time-domain simulation of the ship motions, based on linear potential flow for the outer domain (ship hull and ocean). The computed ship motions are again input for the motions of the liquid tank, generating a 2-way coupling between the dynamics of the tank and the ship. Both methods are applied to sloshing model tests, published by Molin (2008). In these tests, the response of a barge was measured with a completely filled and partially filled tank in beam seas. The results of the linear diffraction method agree reasonably well, but some differences in the roll response near the first sloshing mode are observed. The coupled time-domain method gives very good results for both low and high sea states.
17 citations