Thesis (M.S.)--University of Wisconsin--Madison, 1963. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaf 35).

Thesis (Ph. D.)--Lehigh University, 1997. / Includes vita. Bibliography: leaves 175-185.

Thesis (M.S. in Mechanical Engineering) Naval Postgraduate School, September 1999. / "September 1999." Thesis advisor(s): T. Sarpkaya. Includes bibliographical references (p. 77). Also Available online.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1975. / Typescript. Vita. Includes bibliographical references.

Thesis (M.S.)--University of Wisconsin--Madison, 1981. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 162-165).

Thesis (Ph. D.)--University of Wisconsin--Madison, 1982. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 125-129).

Thesis (MScIng)--University of Stellenbosch, 2006. / Bibliography. Also available via the Internet.

Friction factors have been determined experimentally for longitudinal flow of water and various aqueous solutions of polyethylene glycol between regular enclosed arrays of cylinders. Two different geometries were investigated: a 4 × 4 square array enclosed by a square duct and a 19-rod equilateral triangular array enclosed by a hexagonal duct. Four different pitch-to-diameter ratios were studied in each geometry. These covered a range of 1.07 to 2.00 in the square array and 1.11 to 2.06 in the triangular array. No spacers were used in the rod bundle. The Reynolds number range investigated was approximately 2.5 to 40,000 (equivalent diameter based on total wetted perimeter). The fully developed friction factors for all eight arrays were correlated by the Nikuradse equation for smooth round tubes when the Reynolds number exceeded 10,000 and when the equivalent diameter, used in both the Reynolds number and the friction factor, was taken as four times the hydraulic raduis based on total wetted perimeter. In laminar flow no equivalent diameter was found that would consolidate the results of all eight arrays. Deviations from the laminar flow theory of Sparrow and Loeffler for infinite arrays could be consistently accounted for by the wall effect in the present study. The critical Reynolds number for each array ranged between 90 and 450 (equivalent diameter based on total perimeter) and the transition from laminar to turbulent flow appeared to extend over a large Reynolds number range. Friction factors in both laminar and turbulent flow were apparently established in a very short distance from the entrance to the rod bundle, since no entrance effect was detected, even as close as 9.6 total equivalent diameters from the entrance. Local friction factors were also measured in the entrance and fully developed region of a round smooth tube with a sharp-edged entrance. The Reynolds number range covered was 394 to 77,000. The inside tube diameter, determined by forcing the fully developed laminar flow friction factors to fit Poiseuille's equation, was in excellent agreement with the measured diameter, and the fully developed turbulent flow friction factor results, based on the computed diameter, were in good agreement with Nikuradse's equation for a smooth round tube. The Newtonian behavior of the polyethylene glycol solutions over all rates of shear encountered in the present study was thus established. Good agreement was also obtained between the local laminar flow friction factors, measured in the entrance region of the tube, and those predicted theoretically by Langhaar for a rounded entrance. In turbulent flow, the friction factor became fully developed within 50 tube diameters of the entrance. / Applied Science, Faculty of / Chemical and Biological Engineering, Department of / Graduate

This thesis describes the investigation of hydrodynamic properties of pure superfluid flow in liquid helium II by observing the motion of suspended particles in a special experimental arrangement called 'Superfluid Wind Tunnel'. The flow properties of pure superfluid in different velocity regions have been investigated by using particles made with a suitable mixture of hydrogen and deuterium gases as indicators. Two critical velocities, Vp,c and Vs,c, corresponding to 0c and 0t of the oscillating sphere experiments (Benson and Hallett (1956)) have been found. Below Vp,c, the superfluid flow is a perfect potential flow of zero viscosity. Above Vp,c quantized vortex lines are created, therefore the pure superfluid flow breaks down. On the other hand in the vicinity of Ys,c, the starting point of fully developed turbulence, the magnitude of turbulent fluctuations has a maximum which confirms Feynman's prediction (1955) about critical velocity. A rough calculation shows that the velocities of a particle, which obtains energy from a segment of quantized vortex line, are of the same order as that of experimental values. This suggests that by this way, other than Vinen's (1961) vibrating wire experiment, the quantization of superfluid circulation in units of h/m might be verified by visual observations. / Science, Faculty of / Physics and Astronomy, Department of / Graduate

Friction factors have been determined experimentally for flow of water and various aqueous solutions of polyethylene glycol in four different concentric annuli. The annuli studied covered a diameter ratio range of 0.0406 to 0.6331. The annular entrance was sharp-edged and no spacers were used within the system. The Reynolds number range investigated was approximately 200 to 26,000, based on equivalent diameter equal to four times the hydraulic radius. The fully developed friction factors for all four diameter ratios were correlated by the Nikuradse equation for a smooth pipe when the Reynolds number exceeded 3500 and by the Knudsen and Kata theory for laminar flow when the Reynolds number was less than 2200. Deviations from the theory of Hanks for laminar - turbulent transition in the well-developed flow region of concentric annuli could be tentatively accounted for by the extra turbulence arising from the sharp-edged entrance in the present investigation. For well-developed flow the critical Reynolds numbers for the various diameter ratios ranged between 2650 and 3700, and the mode of transition was sharp. However, for low, intermediate and high values of entrance length, respectively, three different modes of transition were found to exist in the annuli studied. Local friction factors were based on pressure gradient, uncorrected for changes in kinetic energy due to the developing velocity profile. / Applied Science, Faculty of / Chemical and Biological Engineering, Department of / Graduate