Shape Optimization of Hydrofoils

In this thesis, a genetic algorithm: GA) is employed for shape optimization of hydrofoils for application in a sailing craft. The hydrofoil for a sailing craft should have high lift at lower speeds and low drag at higher speeds. Computations are performed for a hydrofoil in deep water as well as one close to the free surface. The commercially available software FLUENT is used for calculation of the flow field, and the software GAMBIT is used for the geometry and mesh generation. Volume of Fluid: VOF) method in FLUENT is employed to define the air/water interface. Genetic algorithm is implemented with GAMBIT and FLUENT for shape optimization of hydrofoils. Maximization of lift to drag ratio is used as the optimization criteria. Optimized shapes are obtained for a hydrofoil in deep water at Re = 10 x 106 and Re = 20 x 106 at angles of attack of 0, 2, 4, and 6 degrees. Optimized shapes are also obtained for a hydrofoil near a free surface at d/c = 0.5 where d is the depth under the free surface and c is the chord length of the hydrofoil. It is shown that GA optimization technique is capable of accurately and efficiently finding the globally optimum hydrofoils

Properties of the redshift

Central to any analysis of dynamical systems, or large scale motion, is the interpretation of redshifts of galaxies as classical Doppler velocity shifts. This is a testable assumption and for many years evidence has accumulated that is inconsistent with the assumption. Here, the authors review recent evidence suggesting systematic radial dependence and temporal variation of redshifts

On groups with few subgroups not in the Chermak-Delgado lattice

We investigate the question of how many subgroups of a finite group are not in its Chermak-Delgado lattice. The Chermak-Delgado lattice for a finite group is a self-dual lattice of subgroups with many intriguing properties. Fasol\u{a} and T\u{a}rn\u{a}uceanu asked how many subgroups are not in the Chermak-Delgado lattice and classified all groups with two or less subgroups not in the Chermak-Delgado lattice. We extend their work by classifying all groups with less than five subgroups not in the Chermak-Delgado lattice. In addition, we show that a group with less than five subgroups not in the Chermak--Delgado lattice is nilpotent. In this vein we also show that the only non-nilpotent group with five or fewer subgroups in the Chermak-Delgado lattice is S_3

Data from Tests of a 1/5-Scale Model of a Proposed High-Speed Submarine in the Langley Full-Scale Tunnel

Tests of a 1/5 scale model of a proposed 153-foot high-speed submarine have been conducted in the Langley full-scale tunnel at the request of the Bureau of Ships, Department of the Navy. The test program included: (1) force tests to determine the drag, control effectiveness, and static stability characteristics for a number of model configurations, both in pitch and in yaw, (2) pressure measurements to determine the boundary-layer conditions and flow characteristics in the region of the propeller, and (3) an investigation of the effects of propeller operation on the model aerodynamic characteristics. In response to oral requests from the Bureau of Ships representatives t hat the basic data obtained in these tests be made available to them as rapidly as possible, this data report has been prepared to present some of the more pertinent results. All test results given in the present paper are for the propeller-removed condition and were obtained at a Reynolds number of approximately 22,300,000 based on model length

Receipt for payment from Robert Dickins and Company to William and Mary Cocke, June 25, 1833

This document is part of the John Cocke papers that contains the personal, business, and legal papers of this 19th century Marengo County, Alabama, plantation owner, who not only managed his own plantation but also served as an agent for various family members. Financial papers consist of receipts from grocers and suppliers detailing purchases (including slave purchases); account books for his blacksmith shop; and labor accounts with payroll. There are cotton records that contain correspondence as well as accounts

Receipt for payment from Mr. Waulker to William and Mary Cocke, August 29, 1833

This document is part of the John Cocke papers that contains the personal, business, and legal papers of this 19th century Marengo County, Alabama, plantation owner, who not only managed his own plantation but also served as an agent for various family members. Financial papers consist of receipts from grocers and suppliers detailing purchases (including slave purchases); account books for his blacksmith shop; and labor accounts with payroll. There are cotton records that contain correspondence as well as accounts