Analysis of added mass in cavitating flow

• Published in: Journal of fluids and structures Vol. 31; pp. 30 - 48
• Main Authors: Benaouicha, Mustapha, Astolfi, Jacques-André
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01.05.2012; Elsevier; ELSEVIER
• Subjects: Added mass; Cavitation; Cavitation induced vibrations; Computational fluid dynamics; Computational methods in fluid dynamics; Damping; Density; Engineering Sciences; Exact sciences and technology; Fluid dynamics; Fluid flow; Fluids; Fluids mechanics; Fluid–structure interaction; Fundamental areas of phenomenology (including applications); Mathematical models; Mechanics; Nonhomogeneous flows; Operators; Physics; Solid mechanics; Structural and continuum mechanics; Structural mechanics; Vibration, mechanical wave, dynamic stability (aeroelasticity, vibration control...); Fluid–structure interaction; Added mass; Cavitation induced vibrations; Laplace equations; Fluid-structure interactions; Unsteady flow; Eigenfrequency; Density distribution; Cavitating flow; Cavitation; Fluid-structure interaction; Vibrations; Space-time; Vibration damping; Non viscous fluid; Modelling; Turbulence structure
• ISSN: 0889-9746; 1095-8622
• DOI: 10.1016/j.jfluidstructs.2012.03.003

The paper addresses a theoretical study of the added mass effect in cavitating flow. The cavitation is considered to induce a strong time–space variation of the fluid density at the interface between an inviscid fluid and a three-degree-of-freedom rigid section. The coupled problem is then simplified to a Laplace equation written for the pressure with a boundary condition at the fluid–structure interface depending on the acceleration, the velocity of the structure and on the rate of change of flow density. It is shown that contrary to the homogeneous flow, the added mass operator is not symmetrical and depends on the flow through fluid density variation. The added mass coefficients decrease as the cavitation increases which should induce an increase of the natural structural frequencies. The model shows also an added damping operator related to the rate of change of flow density. Added damping coefficients are found to be positive or negative according to the rate of change of the fluid density, indicating the possibility of instability development between flexible structures and unsteady cavitating flows.