This work studies optimized controls which minimize the heat load at the stagnation point of an ascending hypersonic flight vehicle. Two types control schemes are studied, namely, a polynomial type of feedback controller and a neural controller. To validate the results obtained …
"52" Result
Sort By:
An automatic image processing technique and a comprehensive formulation of depth of field effects for particle analysis are presented. The image processing method operates on original, unenhanced particle images where the background intensity can be non-uniform, and particle siz…
The problem of combined natural convection and radiation heat transfer of a gray absorbing-emitting and isotropically scattering medium in a triangular enclosure is solved numerically in this dissertation. Interactions of natural convection and radiation occur in many engineerin…
This study explores parallel fuel injection as a possible candidate for a supersonic air breathing propulsion device and also explores the possibility of enhancing fuel-air mixing by varying injector nozzle geometry. An extended two-dimensional strut, with the base generating a …
Dust/sand storms are serious hazards to human activities in Saudi Arabia. Visibility is greatly reduced for aviation operators, and the abrasive effects are very discomforting to personnel and detrimental to structures and equipment. The orientation of the Arabian Peninsula and …
In recent years, acoustic microscopy has been found to be very useful for characterizing engineering as well as biological materials. With the present state of knowledge on acoustic microscopy, one can obtain the surface wave velocity of a homogeneous specimen or coating thickne…
The dissertation investigates formations of a space based exploration system consisting of an interplanetary capable spacecraft and two smaller deployable spacecraft. Spacecraft formations are optimized for single pass spot-light interferometric synthetic aperture radar (IFSAR) …
Numerical simulation of flow past airfoils is important in the aerodynamic design of aircraft wings and turbomachinery components. These lifting devices often attain optimum performance at the condition of onset of separation. Therefore separation phenomena must be included if t…
Results from two distinct investigations are reported in this dissertation. In the first investigation, linearized stability analyses were performed to investigate effects of Marangoni stresses on hydrodynamic stability of bi-component droplets slowly evaporating in a sphericall…
The problem of flutter is first introduced. The equations of motion of an airfoil with two degrees of freedom, in pitch and plunge, are obtained. Then, the unsteady aerodynamic theories for different flow regimes are presented. The traditional solutions to the flutter problem, n…
The control of boundary layer is very important in the field of aerodynamics and hydrodynamics and becomes essential for current wing design technology to increase lift, stalling angle of attack and lift-to-drag ratio. Therefore, an experimental investigation has been conducted …
Future space systems such as Space Station Freedom, and space defense systems will require storage of cryogenic fluids in a low-gravity environment for extended periods of time. Heat leaks to the containment vessel lead to an increase in the temperature and pressure of the fluid…
Mechanical and fluid dampers have been placed at the bearing locations in turbomachinery to stabilize and attenuate vibration levels. Wire mesh, a material formed by compressing woven wires into the desired shape, is used in many industrial applications. This material possesses …
A new analysis was developed to predict rotordynamic coefficients of honeycomb seals with cell size and depth of 1.59 mm and 1.8 mm, respectively. The analysis was based on a new friction factor model and entrance loss coefficient. The experimental friction factor model for a ho…
An experimental study was undertaken to elucidate the mixing enhancement and noise reduction in a jet caused by tabs, simple protrusions into the flow, placed at the nozzle exit. Far-field acoustic spectra of underexpanded jets showed the elimination of screech and a decrease in…
Recent advances in many fields have made the design of micro-aerial vehicles that implement flapping wings a possibility. However, there are many outstanding problems that must be solved before flapping flight can be implemented as a practical means of propulsion. This dissertat…
Since probe theory was developed, the problem of current collection by a charged spherically or cylindrically symmetric body has been investigated by a number of authors (e.g. Parker and Murphy, 1967; Linson, 1969; Laframboise and Rubinstein, 1976). The purpose of this paper is …
A parallel approach to the solution of a turbulent flow problem was developed. Our approach was highly parallelized. Two-dimensional channel flow at known and unknown pressure gradient was studied. The study was divided into two phases. In phase one, fully developed channel flow…
Economic considerations have forced users of commercial jet transports to retain the services of aircraft that have surpassed the designed lifetime of structural components of the aircraft. With the increased service time that these aircraft are experiencing, many of the aircraf…