Experimental study of expansion and compression effects on the stability of Taylor vortex flow

• Published in: Fluid dynamics research Vol. 48; no. 4; pp. 45502 - 45516
• Main Authors: Mansour, M, Ali, M H, El-Maksoud, R M Abd
• Format: Journal Article
• Language: English
• Published: IOP Publishing 01.08.2016
• Subjects: Compressing; Cylinders; End plates; Fluid dynamics; Fluid flow; Laminar flow; rotating flow; Stability; Taylor vortex flow; Taylor-Couette instability; Time dependence
• ISSN: 0169-5983; 1873-7005
• DOI: 10.1088/0169-5983/48/4/045502

The aim of the present experimental work is to determine the stability limits of Taylor cells by expanding and compressing the cells. The investigation was performed under laminar flow condition with a wide gap between an inner rotating cylinder and outer stationary cylinder. In order to allow the expansion and compression of the cells, the test rig was designed with a sliding upper end plate and a fixed lower end plate. The objectives are to determine the maximum and minimum size limits of each number of cells as well as the stability margin of them. Since, unstable cells have various oscillations and time dependent structures which change the behavior of the flow; the investigations of the stability limits is quite necessary to avoid the possible generation of unstable cells. In addition, the results are used to detect the number of cells that can be generated in the gap at different fluid column lengths. A stability map, locating the stability state of all possible numbers of cells, is assigned in the results. The map provides overlap zones between stable cells, in which the operating conditions will always lead to stable cells, even if the number of cells is changed by changing the initial conditions. Moreover, a rare phenomenon was observed during the compression process when the cells jumps unusually from six to two cells without passing through the four-cell mode.