Hostname: page-component-7479d7b7d-q6k6v Total loading time: 0 Render date: 2024-07-12T20:42:45.191Z Has data issue: false hasContentIssue false

An experimental study on stationary history effects in high-frequency Stokes flows

Published online by Cambridge University Press:  16 April 2004

C. F. M. COIMBRA
Affiliation:
Department of Mechanical Engineering, University of Hawaii–Manoa, Honolulu, HI 96822, USA
D. L'ESPERANCE
Affiliation:
MetroLaser Incorporated, 2572 White Road, Irvine, CA 92614, USA
R. A. LAMBERT
Affiliation:
Department of Mechanical and Aerospace Engineering, University of California, Irvine, CA 92826, USA
J. D. TROLINGER
Affiliation:
MetroLaser Incorporated, 2572 White Road, Irvine, CA 92614, USA
R. H. RANGEL
Affiliation:
Department of Mechanical and Aerospace Engineering, University of California, Irvine, CA 92826, USA

Abstract

We report results of a series of detailed experiments designed to unveil the dynamics of a particle of radius $a$ moving in high-frequency, low-Reynolds-number oscillatory flow. The fundamental parameters in the problem are the Strouhal ($\hbox{\it Sl}$) and the particle Reynolds numbers ($\hbox{\it Re}_p$), as well as the fluid-to-particle density ratio $\alpha$. The experiments were designed to cover a range of $\hbox{\it Sl} \hbox{\it Re}_p$ from 0.015 to 5 while keeping $\hbox{\it Re}_p < 0.5$ and $\hbox{\it Sl} > 1$. The primary objective of the experiments is to investigate stationary history effects associated with the Basset drag, which are maximized when the viscous time scale $a^2/\nu$ is of the same order of the flow time scale $9/\Omega$, where $9$ is a geometrical factor for the sphere, $\nu$ is the kinematic viscosity and $\Omega$ is the angular frequency of the background flow. The theoretically determined behaviour of stationary history effects is confirmed unequivocally by the experiments, which also validate the fractional derivative behaviour (of order $1/2$) of the history drag for the range of parameters under study.

Type
Papers
Copyright
© 2004 Cambridge University Press

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)