Numerical Investigation of Centrifugal Instability Around a Circular Cylinder Rotated Impulsively

Prabhu, Akhilesh M and Shukla, Ratnesh K and Arakeri, Jaywant H (2016) Numerical Investigation of Centrifugal Instability Around a Circular Cylinder Rotated Impulsively. In: IUTAM Symposium on Advances in Computation, Modeling and Control of Transitional and Turbulent Flows, DEC 15-18, 2014, Goa, INDIA, pp. 146-154.

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Abstract

The inception and growth of centrifugally driven instabilities around an impulsively rotated cylinder is investigated through direct numerical simulations. Full three-dimensional simulation at a Reynolds number (Re) of 200, shows that the initial instability manifests as axisymmetric toroidal vortices stacked periodically along the cylinder axis. Based on this finding, two-dimensional axisymmetric simulations are performed for Reynolds numbers spanning seven orders of magnitude. A critical wavelength lambda(c), defined as the wavelength of the first unstable mode is calculated over a range of Reynolds numbers based on the cylinder radius and wall velocity. A critical boundary layer thickness delta(c) is defined based on vorticity and is found to scale as Re-2/3 at large Reynolds numbers. The critical wavelength.c exhibits a similar scaling, so that lambda(c) similar to delta(c) for Re >> 1. A Taylor number based on the wavelength of the instability as the characteristic length scale is defined and its variation with the Reynolds number is discussed.

Item Type:	Conference Proceedings
Publisher:	World Scientific
Additional Information:	Copyright for this article belongs to the WORLD SCIENTIFIC PUBL CO PTE LTD, PO BOX 128 FARRER RD, SINGAPORE 9128, SINGAPORE
Department/Centre:	Division of Mechanical Sciences > Mechanical Engineering
Date Deposited:	22 Oct 2016 09:33
Last Modified:	19 Jul 2019 17:33
URI:	http://eprints.iisc.ac.in/id/eprint/55046

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