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Title: An experimental and numerical investigation into the vertical dependence of Taylor-columns generated by a rotating disc
Author: Vlaskamp, Jozef H. A.
ISNI:       0000 0004 2725 3905
Awarding Body: University of Warwick
Current Institution: University of Warwick
Date of Award: 2011
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The presence of strong background rotation changes the dynamics of the fluid dramatically. The Taylor-Proudman theorem states that no variation in the velocity field may exist parallel to the axis of rotation when geostrophy applies. One of the most important implications of the Taylor- Proudman theorem is the presence of Taylor-Columns around solid objects moving in the fluid. The study presented here considers the Taylor- Columns generated by a differentially rotating disc located on the axis of rotation of a rotating fluid. The Taylor-Column rotates at an angular velocity intermediate to the disc and the tank, and is bounded by a vertical free shear layer. The large turntable at the University of Warwick allows a series of unique experiments to be performed in very deep water at high h/r, with h the water depth and r the disc radius. A direct numerical simulation has been performed in spherical geometry, at h/r of 5,10 and 20 and Ekman numbers of 10-5 < E < 10-2. The results show the classic solution with no vertical dependence as predicted by the Taylor-Proudman theorem. For the experimental investigation, a fully automated, traverse mounted stereo-PIV system has been developed which provides data-acquisition at different heights in the Taylor-Column. This allows investigation of the vertical dependence of the flow. Experiments have been performed with E~10-3 and h/r = 80. For positive differential disc rotation, a vertical dependence in the angular velocity was found, contradicting the Taylor- Proudman theorem and the numerical predictions. For negative differential rotation, this vertical dependence was not found. Stratification due to temperature gradients in the flow are suggested as a possible cause for the observed discrepancy.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available
Keywords: QA Mathematics ; TA Engineering (General). Civil engineering (General)