.. _R4.07.03:

**r4.07.03** Mass matrix calculation added on a modal basis
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**Summary:**

This document presents an aspect of fluid/structure coupling: when a vibrating structure is surrounded by a fluid that is assumed to be flowless, incompressible and non-viscous, it experiences pressure forces whose resultant is proportional to the acceleration of the structure in the fluid: the coefficient of proportionality is homogeneous to a mass: it is called **added mass**. Here we specify the means of constructing an added mass matrix for one (or more) structures with several degrees of freedom on the modal basis of the structure (s) established beforehand in the absence of fluid. This matrix of added mass is obtained under the hypothesis of small movements for both the structure and the fluid.




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    Notations
    Introduction
    Rappels_des__quations_du_probl_me
    Mise_en__uvre_num_rique
    Mise_en__uvre_dans_Code_Aster
    Bibliographie
    Description_des_versions_du_document