Publication Date:
2004-04-10
Description:
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 (SI) and the particle Reynolds numbers (Rep), as well as the fluid-to-particle density ratio α. The experiments were designed to cover a range of S/Rep from 0.015 to 5 while keeping Rep 〈 0.5 and S1 〉 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 a2/v is of the same order of the flow time scale 9/Ω where 9 is a geometrical factor for the sphere, v is the kinematic viscosity and Ω 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. © 2004 Cambridge University Press.
Print ISSN:
0022-1120
Electronic ISSN:
1469-7645
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
,
Physics
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