The axisymmetric laminar boundary-layer flow along a circular cylinder under an accelerated free-stream is investigated. Considering flow past a slender cylinder, the boundary-layer equations are developed with a linear velocity-slip and temperature-jump boundary condition imposed near the cylinder wall. For small and large axial distances, series solutions are obtained for the Bingham and Nusselt numbers; these take account of prescribed values of momentum and temperature-slip coefficients and the index of acceleration; at intermediate axial distances, exact and interpolated numerical solutions are obtained. In addition, the flow past a Rankine half-body is considered. Given a prescribed Reynolds number, asymptotic series solutions for the non-dimensional drag coefficient for flow close to the forward stagnation point and downstream are obtained; for intermediate flow) the solution is obtained by interpolation. The unsteady case is then investigated. in which the boundary-layer flow along a cylinder of infinite extent moves impulsively from rest with both uniform velocity and acceleration under velocity-slip. Consideration is then given to the case in which an infinite stationary cylinder is impulsively heated in still-air having a fixed temperature, while a temperature-jump boundary condition is imposed. In relation to non-dimensional time, the Bingham and Nusselt numbers are derived analytically by means of Laplace transform techniques. Finally, the amplitude of a disturbance caused by an air draught acting on a part of the fibre in the melt-spinning process is investigated.. The flow, modeled as a wave propagating on a moving string, takes account of the influence of air drag and variable tension. Using the method of characteristics, the disturbance amplitude is analytically obtained along the leading characteristics that emanate from the boundaries of the localised. initial disturbance while the general solution of the damped disturbance is numerically evaluated. The magnitude of the disturbance is determined for the region close to the orifice where the extruded polymer is molten and thus, susceptible to disturbances.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:601331 |
| Date | January 2011 |
| Creators | McVeigh, Anthony G. |
| Publisher | University of Buckingham |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
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