No description available.

No description available.

No description available.

No description available.

No description available.

No description available.

This thesis concerns incompressible, planar, two-dimensional flow past impervious and porous bluff membranes as well as impervious streamlined membranes or planar sails. Each membrane was held by two supports which were thin relative to the distance between them. The angle between the flow direction and the line joining the supports was set at right angles for the bluff membranes and at small angles for the streamlined membranes. Experiments were made for various membrane lengths as a proportion of the distance between the supports. Materials of different density and porosity were used for the bluff membranes. A theory, based on Bearman-Fackrell's numerical solution of Parkinson-Jandali's wake-source model for bluff bodies, was developed for the impervious and porous bluff membranes and found to give good prediction of the drag coefficient. Previous theoretical solutions for the planar sail showed serious disagreement with the experimental results mainly because of flow separation.

The nature of flow in stratified reservoirs has been studied and a method developed, based on a laboratory model study, to predict the quality of the water discharged from the reservoir. The experimental data has been evaluated in dimensionless form, so that the results may be applied to actual reservoirs. The model was designed to simulate a relatively high head dam impounding a stratified reservoir in which the density gradient is approximately linear. The extent and magnitude of internal density currents can be determined, and the properties of the discharged water can be predicted from measurements of flow rate, density gradient, and depth. The temperature of the discharged water, effect on downstream environment, and change in the thermal structure of the reservoir are among the quantities which may be forecast. Illustrations have been provided to show the degree of control of water quality available by regulation of the reservoir water discharge. / Graduation date: 1966

Thesis (Ph. D.)--University of Hawaii at Manoa, 1995. / Includes bibliographical references (leaves 147-152). / Microfiche. / xviii, 152 leaves, bound ill. 29 cm

The purpose of this thesis is to study the problem of a low Reynolds number swimmer that is in very close proximity to a wall or solid boundary in a non- Newtonian fluid. We assume that it moves by propagating waves down its length in one direction, creating a thrust and therefore propelling it in the opposite direction. We model the swimmer as an infinite, inextensible waving sheet. We consider two main cases of this swimming sheet problem. In the first case, the type of wave being propagated down the length of the swimmer is specified. We compare the swimming speeds of viscoelastic shear thinning, shear thickening and Newtonian fluids for a fixed propagating wave speed. We then compare the swimming speeds of these same fluids for a fixed rate of work per wavelength. In the latter situation, we find that a shear thinning fluid always yields the fastest swimming speed regardless of the amplitude of the propagating waves. We conclude that a shear thinning fluid is optimal for the swimmer. Analytical results are obtained for various limiting cases. Next, we consider the problem with a Bingham fluid. Yield surfaces and flow profiles are obtained. In the second case, the forcing along the length of the swimmer is specified, but the shape of the swimmer is unknown. First, we solve this problem for a Newtonian fluid. Large amplitude forcing yields a swimmer shape that has a plateau region following by a large spike region. It is found that there exists an optimal forcing that will yield a maximum swimming speed. Next, we solve the problem for moderate forcing amplitudes for viscoelastic shear thickening and shear thinning fluids. For a given forcing, it is found that a shear thinning fluid yields the fastest swimming speed when compared to a shear thickening fluid and a Newtonian fluid. The difference in swimming speeds decreases as the bending stiffness of the swimmer increases.