Stability characteristics of suspension flow through wavy-walled channels

• Published in: Acta mechanica 2005-04, Vol.176 (1-2), p.1-26
• Main Authors: USHA, R, SENTHILKUMAR, S, TULAPURKARA, E. G
• Format: Article
• Language: English
• Subjects: Exact sciences and technology; Flow control; Flows in ducts, channels, nozzles, and conduits; Fluid dynamics; Fundamental areas of phenomenology (including applications); Multiphase and particle-laden flows; Nonhomogeneous flows; Numerical analysis; Physics; Reynolds number; Waveform analysis
• ISSN: 0001-5970; 1619-6937
• DOI: 10.1007/s00707-004-0195-x

A numerical study of the linear temporal stability characteristics of particulate suspension owthrough a converging-diverging symmetric wavy-walled channel is considered. The basic ow is a superposition of plane channel ow of particulate suspension and periodic ow components arising due to the small amplitude sinusoidal waviness of the channel walls. The disturbance equations are derived within the framework of Floquet theory and solved using the spectral collocation method. The eects of small amplitude sinusoidal waviness of the channel walls and those of the presence of particles on the initial growth of the disturbances are examined. Two-dimensional stability calculations for particulate suspensions indicate the presence of fast growing unstable modes that arise due to the waviness of the walls. Neutral stability calculations are performed in the disturbances wave number-Reynolds number (as Re) plane, for the wavy channel with representative values of wavenumber (k) and the wall amplitude to semichannel height ratio (w) for different values of volume fraction density of the particles (C). It is observed that the critical Reynolds number for transition decreases with increase of w and C. [PUBLICATION ABSTRACT]