Non-linear hydrodynamics of thin laminae undergoing large harmonic oscillations in a viscous fluid

• Published in: Journal of fluids and structures Vol. 52; pp. 101 - 117
• Main Authors: Tafuni, Angelantonio, Sahin, Iskender
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.01.2015
• Subjects: Added mass; Computational fluid dynamics; Fluid flow; Fluid–structure interaction; Harmonics; Hydrodynamic function; Hydrodynamics; Laminates; Mathematical analysis; Mathematical models; Non-linear damping; Oscillations; Smoothed Particle Hydrodynamics; Viscous fluid; Viscous fluids; Smoothed Particle Hydrodynamics; Added mass; Fluid–structure interaction; Non-linear damping; Viscous fluid; Hydrodynamic function
• ISSN: 0889-9746; 1095-8622
• DOI: 10.1016/j.jfluidstructs.2014.10.004

Smoothed Particle Hydrodynamics is implemented to study the motion of a thin rigid lamina undergoing large harmonic oscillations in a viscous fluid. Particularly, the flow physics in the proximity of the lamina is resolved and contours of non-dimensional velocity, vorticity and pressure are presented for selected oscillation regimes. The computation of the hydrodynamic load due to the fluid–structure interaction is carried out using Fourier decomposition to express the total fluid force in terms of a non-dimensional complex-valued hydrodynamic function, whose real and imaginary parts identify added mass and damping coefficients, respectively. For small oscillations, the hydrodynamic force reflects the harmonic nature of the displacement, whereas multiple harmonics are observed as both the amplitude and frequency of oscillation increase. We propose a novel formulation of hydrodynamic function that incorporates added mass and damping coefficients for a thin rigid lamina spanning large amplitudes in viscous fluids in a broad range of the oscillation frequencies. Results of the simulations are validated against numerical and experimental works available in the literature in addition to theoretical predictions for the limit case of zero-amplitude oscillations. •We investigate oscillations of thin rigid laminae in a viscous fluid using SPH.•Oscillation amplitudes are in the range [2–70%] of the lamina characteristic length.•We identify vorticity transport as the leading mechanism driving hydrodynamic damping.•Added mass does not vary substantially with the oscillation amplitude.•Hydrodynamic damping is strongly affected by the oscillation amplitude.