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Title: Semi-cylindrical structures in turbulent boundary layers
Author: Tahouri, Bahman
ISNI:       0000 0001 3495 9293
Awarding Body: University of Surrey
Current Institution: University of Surrey
Date of Award: 1993
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Mean surface pressure distributions on surface-mounted semi-cylindrical bodies, together with associated near wake flow regimes were investigated. The work was carried out by undertaking wind tunnel measurements on two and three-dimensional models. The effects of changes in the model cross sectional geometries and aspect ratio, approach flow conditions, model surface roughness and Reynolds number on the mean surface pressures were investigated. In particular, the Reynolds number dependency of the mean pressure distributions was analysed in depth and a post-critical Reynolds number flow was simulated by using artificial surface roughness at subcritical Reynolds numbers. Whilst qualitative flow visualisation studies identified the extent of the near wake region of each model, pulsed-wire measurements of mean velocities and turbulence intensities in the recirculation region of each model provided detailed information on the near wake flows. The separated shear layers associated with the three-dimensional semi-cylindrical models were found to be highly curved in contrast to those associated with two-dimensional blocks and steps. Measurements of surface pressures on semi-cylinders, sheltered by upstream model fences or identical semi-cylindrical bodies, identified the effects of the sheltering parameters in reducing the magnitude of the pressures on the sheltered body. During the course of the present work, the control circuitry of an existing instrument used for estimating the positions of flow separation and reattachment was designed and developed. The control software for this instrument together with those of the mean pressure measurement apparatus, the pulsed-wire anemometer and traversing mechanisms were also developed and utilised.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available
Keywords: Fluid mechanics