Experimental and theoretical investigations of a supercavitating hydrofoil

An experimental investigation of the two-dimensional hydrodynamic characteristics of a thin, supercavitating hydrofoil is described. The effects of twist and vibration of the thin hydrofoil model are considered, and experimental techniques for investigating spanwise twist and leading edge vibration and data correction methods are described. The theory of Wu for the forces on fully cavitating hydrofoils was used to calculate the forces on this profile. The calculated lift is in good agreement with the experimental results; however, the measured drag differs appreciably from the theoretical values

Cavity Shapes for Circular Disks at Angles of Attack

The shape of the cavity formed in ;·rater by a circular disk at an angle of attack is derived. The empirical evaluation is based on experimental data obtained with air cavities in the Free Surface Water Tunnel. The effects of model size, free stream velocity and cavitation number on cavity shape are presented. The profile shape of the cavity is assumed to be composed of two superposable phenomena: (1) the cavity shape without gravity effects (2) the displacement of the cavity due to gravity An empirical relation is obtained for the buoyant displacement of the cavity centerline. A quasi-elliptical equation is derived which accurately describes the shape of the cavity about its centerline for the disk at zero angle of attack. The equation is modified and applied to the profile shape of a cavity formed by a circular disk at angles of attack up to 30 degrees. All experimental data are presented in both graphic and analytic form

Terminal Sinking Velocities for a Series of Flat Nosed Bodies

Drag studies were made on a series of models having varying degrees of bluntness and varying length-to-diameter ratios. Using the drag coefficients obtained from the tests, terminal sinking velocities in sea water were calculated for various volumes and densities. It was found that the terminal sinking velocity of a blunt-nosed body could be increased 15 percent if the length-to-diameter ratio was increased from 7 to 14 for the same volume. The terminal sinking velocity of a fine-nosed body could be increased only 2 percent if the length-to-diameter ratio was increased from 6 to 12

Hydrodynamic Coefficients of the MK 13-2 Torpedo

Force measurement runs were made on a model MK 13-2 Torpedo to correct previously reported results for the discrepancies which were attributable to the interaction of pitching moment on the force measuring apparatus. The plain body, the body with fins, and the body with a shroud ring tail were tested at yaw angles of -10 degrees to +10 degrees. Drag-force coefficients, cross-force coefficients, and yawing moment coefficients were calculated and are presented in this report

Forces on Composite Bodies in Full Cavity Flow

Experimental force measurements on several truncated cone-cylinder bodies operating in full cavity flow are reported. Lift, drag and pitching moment coefficients and the center of pressure are presented as functions of angle of attack for cavitation numbers from 0.02 to 0.06. The lift and drag coefficients are compared with predicted results which are based on the summation of the forces on individual body components. Discrepancies between the experimental and the predicted results are discussed

Water Tunnel Investigation of Two-Dimensional Cavities

The results of drag measurements on a flat lamina, wedges, a circular cylinder and a scoop channel in two- dimensional cavitating flow in the High Speed Water Tunnel are presented. Cavity geometry data are also included. The results are compared with available theoretical drag coefficients and cavity dimensions

A Scale Model Investigation of the Effect of Jet Configuration on Skin Friction for the MK-40 Torpedo

An analytical study, combining jet diffusion patterns and jet velocities, indicates that there are four methods of eliminating the clinging jet phenomenon which occurs on the Mk-40 Torpedo Test Vehicle. It is shown that extension of the nozzles along the existing nozzle axis appears to present the simplest method of design improvement. Experiments were conducted on a modified model of the Mk-40 to verify the analysis. It was found that for the operational jet-to-model velocity ratio, (U/V) of 2, a nozzle extension of 6 nozzle diameters is the minimum required to provide cling-free performance. All experiments and calculations were made for the case of a body without exhaust ports or gas discharge

A Model Study of the Effect of Jet and Exhaust Flow on Drag of the Torpedo Test Vehicle MK 40 X-1

Experimental investigations of the effects of jets and exhaust on a model of the TTV Mk 40 X-1 are discussed. Photographs of the model jet and exhaust flow patterns are presented. Model pressure distribution data and afterbody drag coefficients are shown for numerous flow conditions. Many correlations among the observed phenomena are discussed. Several estimates of prototype jet- and exhaust-induced drag forces are presented. The susceptibility of the configuration to cavitation is discussed. Detailed analyses of the model results as they pertain to the prototype external flow phenomena are presented. Possible fields of study are suggested which could lead to improved prototype performance characteristics

Water Tunnel Investigation of Two-Dimensional Cavities

The results of drag measurements on a flat lamina, wedges, a circular cylinder and a scoop channel in two- dimensional cavitating flow in the High Speed Water Tunnel are presented. Cavity geometry data are also included. The results are compared with available theoretical drag coefficients and cavity dimensions

Estimates of average energy requirements in Bangladesh: Adult Male Equivalent values for use in analyzing household consumption and expenditure surveys.

This dataset contains Adult Male Equivalent (AME) values for use in Bangladesh. These were constructed using prescriptive nutritional constructs adapted to the actual growth and weight pattern seen in Bangladesh. This dataset provides a common base to facilitate for future work with household consumption and expenditure data in Bangladesh while updating the average energy requirements for infants and young children for the WHO 2006 growth standards and 2007 growth reference curves