Rapid Reliable Solution
of the Parametrized Partial Differential Equations
of Continuum Mechanics and Transport

Overview

The "addedmass" Problem in Hydrodynamics
Forward Problem

Authors: G Rozza & AT Patera
in collaboration with DBP Huynh & NC Nguyen


 

Engineering Motivation

In this Worked Problem we provide a simple model to compute the added mass of a parametrized rectangular body in order to get added mass calculations not yet available in the literature. This is a simple hydrodynamics problem. Its applications are well known and important not only in marine hydrodynamics and relatedly in naval architecture and ocean engineering (including oil drilling platforms), but also in more general fields studying floating and buoyancy effects.

Physical Principles

In this Worked Problem we consider bodies floating into inviscid and incompressible flows using a potential flow model.
In fluid mechanics, added mass is the inertia added to a system because an accelerating or decelerating body must move some volume of surrounding fluid as it moves through it, since the object and fluid cannot occupy the same physical space simultaneously. For simplicity this can be modeled as some volume of fluid moving with the object, though in reality ``all" the fluid will be accelerated, to various degrees. ...

All bodies accelerating in a fluid will be affected by added mass, but since the added mass is dependent on the density of the fluid, the effect is often neglected for dense bodies falling in much less dense fluids. For situations where the density of the fluid is comparable to or greater than the density of the body, the added mass can often be greater than the mass of the body and neglecting it can introduce significant errors into a calculation.
... from Wikipedia accessed on 19 June 2008.
Also see, for example, JN Newman, Marine Hydrodynamics, MIT Press, 1977.
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