Engineering Commons^™

Aerodynamics Of Closely Coupled Wings For Varying Chords And Airfoil Planforms, Gary D. Vincent

Masters Theses

"Aerodynamic characteristics of a dual wing aircraft were analyzed with variations in airfoil sections and chord ratios over existing equal chard ratio dual wing and monoplane aircraft designs. Two- and three-dimensional aerodynamic studies were conducted to find the wing geometry which would create the minimum cruise drag. The two-dimensional aerodynamic data was obtained from a multi-element inviscid vortex panel program coupled to a momentum integral boundary layer program to account for the aerodynamic coupling between the wings. With this data, a three-dimensional vortex lattice program calculated the three-dimensional aerodynamic data. compared to an equal chard ratio dual wing aircraft, lower …

Influence Of Nonequilibrium Radiation And Shape Change On The Flowfield Of A Jupiter Probe With Ablation And Mass Injection, Sundaresa Venkata Subramanian

Mechanical & Aerospace Engineering Theses & Dissertations

The influence of nonequilibrium radiative energy transfer and the effect of probe configuration changes on the flow phenomena around a Jovian entry body is investigated. The radiating shock-layer flow is assumed to be axisymmetric, viscous, laminar and in chemical equilibrium. The radiative transfer equations are derived under nonequilibrium conditions which include multi-level energy transitions. The equilibrium radiative transfer is calculated with an existing nongray radiation model which accounts for molecular band, atomic line and continuum transitions. The nonequilibrium results are obtained with and without ablation injection in the shock layer. The nonequilibrium results are found to be influenced greatly by …

Analytic And Experimental Studies Of A True Airspeed Sensor, Joseph Yao-Cheng Shen

Mechanical & Aerospace Engineering Theses & Dissertations

The objective of this study was to analyze and design a true airspeed sensor which will replace the conventional pitot-static pressure transducer. This sensor should have the following characteristics: the flow phenomenon is vortex procession, or the "vortex whistle", it should have no moving parts, and also is to be independent of temperature, density, altitude or humidity changes. This sensor has been designed mainly for small commercial aircraft with the airspeed up to 321.9 km/hr (200 mph).

In an attempt to model the complicated fluid mechanics of the vortex precession, three-dimensional, inviscid, unsteady, incompressible fluid flow was studied by using …

Aerodynamic Study Of Dual Lifting Surfaces, Kamran Rokhsaz

Masters Theses

"Aerodynamic characteristics of two-dimensional dual airfoil systems have been investigated in an incompressible flow field in the area where improved aerodynamic characteristics are realized, due to the flow field coupling of the two airfoils. A simple analytic model has been developed to demonstrate some of the basic coupling effects in such systems. Laplace's differential equation for the stream-function has been solved numerically to determine the potential flow about dual airfoil geometries of different gap, stagger, and decalage. Two numerical methods have been employed; a finite-difference approach in Cartesian coordinates, for which the mixed boundary conditions have been transformed to the …

Curing And Flow Of Thermosetting Resins For Composite Materials Pultrusion, Howard L. Price Jr.

Mechanical & Aerospace Engineering Theses & Dissertations

Fibrous composite materials for mechanical and structural applications often are expensive due to high labor costs. One economical way of making composites is pultrusion, a manufacturing process in which resin-impregnated fibers are pulled at a constant speed through a heated die which shapes the resin-fiber mass and cures the resin. Most of the work which has been done on the process has been of an empirical nature, with limited understanding of the process principles. Most of the experience with pultrusion has been gained with polyester resins and glass fibers. Very little experience has been gained with higher performance, more costly …

A Study Of A Wind Tunnel Measurement System For Unsteady Pressures Using Pneumatic Transmission Lines, Mohammed Javed Khan

Theses and Dissertations

The application of pneumatic transmission lines theory to a tube-scanning valve system for unsteady pressure measurements in the AFIT 5-foot wind tunnel is investigated. Transfer gains of various tube-scanning valve configurations were experimentally measured and the validity of a theoretical model verified for a frequency range of 20 Hz to 140 Hz. The selected system having a 0.0625-in. ID flexible tube of 84 in. length connected to a scanning valve was installed in the wind tunnel. Unsteady pressures introduced over an 18 percent airfoil at zero angle of attack were measured with this system. Data were collected for 0, 40, …

Evaluation Of Hydrogen As A Cryogenic Wind Tunnel Test Gas, Richard Carl Haut Ii

Mechanical & Aerospace Engineering Theses & Dissertations

A theoretical analysis of the properties of hydrogen has been made to determine the suitability of hydrogen as a cryogenic wind tunnel test gas. By using Cryogenic hydrogen, instead of air or cryogenic nitrogen, as the wind tunnel test gas, a significant increase in the test Reynolds number may be achieved without increasing the aerodynamic loads. Under sonic conditions, for example, compared to air at ambient temperature, cryogenic hydrogen at a pressure of one atmosphere produces an increase in Reynolds number of a factor of approximately fourteen while cryogenic nitrogen, at the same pressure, produces an increase of only a …

Experimental Determination Of Improved Aerodynamic Characteristics Utilizing Biplane Wing Configurations, Elmer Carl Olson

Masters Theses

"Improving the aerodynamic characteristics of an airplane with respect to a higher lift coefficient, a lower drag coefficient and a higher lift over drag ratio as a function of angle of attack will make it more efficient, thus conserving energy or improving performance. Investigations were carried out to determine if the aerodynamic characteristics of biplane wing systems could be made more efficient, for low subsonic speeds, than a monoplane of comparable area and aspect ratio. A variable position three-dimensional biplane wing system, and a fuselage that could be fitted with a monoplane wing or the variable position biplane wing system …

Parametric Resonance Of A Beam Subjected To A Sawtooth, Axial Force, Alfred George Richardson

Masters Theses

"This study considers the response of a perfectly elastic straight beam subjected to a periodic, non-harmonic, axial load. A two-mode solution is sought and the effects of axial inertia are included in the analysis. General equations of motion for the beam are developed and their stability is studied with the aid of an analog computer. Results are presented in graphical form. Regions of instability are defined for both modes. A region of combination resonance is also found to occur for the case of a two-mode solution with axial inertia. Typical response curves are presented and the effects of axial inertia …

An Optical Detector Of Water Droplets Within A Thermal Diffusion Chamber, Duane Burton Bush

Masters Theses

"A technique is investigated for counting water droplets formed in a vertical plate steady flow thermal diffusion chamber designed to count cloud condensation nuclei. The counting technique utilizes light scattering. The light source is a He-Ne laser. The detector is a photomultiplier tube. The technique differs from that used in instruments manufactured by Bausch and Lomb, Royco, Climet, etc., in that the aerosol is not passed through a capillary tube. Instead, the viewed volume is optically defined.

It was found that in the configuration tested, the viewed volume is not well enough defined for use with polydisperse aerosols, although the …

Experimental Studies Of Supporting Wire Disturbances In The Near Viscous Wakes Of Slender Supersonic Bodies, Kenneth Anthony Mirly

Masters Theses

"Wires have often been used as a means of mechanically supporting a model so that its wake will be relatively free of support interference. Such support systems have many advantages over stings and are less costly than magnetic suspension systems. Investigations into the disturbances caused by these supporting wires have been carried out with the use of a two-dimensional flat plate and a wire supported slender cone. The tests were conducted in the University of Missouri-Rolla axisymmetric, supersonic wind tunnel at Mach 3.15, and at a Reynolds number of 2.14 X 10⁶ per inch. Schlieren photography, pitot and static pressure …

Design And Preliminary Testing Of A Rotary Internal Combustion Engine, Frank Darrell Statkus

Masters Theses

"With the advent of legislation against pollution, and rising wage, manufacturing, and materials costs, the prime mover industry is presently intent on developing new economical, non-polluting methods of power. It was the hope of the author that the engine described herein would provide an advancement towards meeting the new requirements. The design and resulting prototype is an eight cylinder rotary internal combustion engine, weighing approximately sixty pounds, and operating on the tour stroke principle. Theoretical calculations were made to determine ideal horsepower, mean effective pressure, and efficiency. Ideal horsepower ranged from 38.7 to 62.8. A dynamic analysis of the pistons …

A Closed Form Method For Predicting The History Of Circular Orbit Altitude Decay Of A Near-Earth Satellite Including The Effect Of A Dynamic Atmosphere, John Copley Buchholtz

Masters Theses

"A closed form expression for the time to decay between two circular orbit altitudes is developed. The long-term dynamic variation of high altitude atmospheric density is included. The density is approximated as a ratio of two quadratics with the numerator being a function of the time-related exospheric temperature and the denominator being a function of altitude. The 11-year cyclic variation of exospheric temperature is then represented as a piecewise linear function of time. The analytic expression for circular orbit altitude decay rate is developed by describing the energy loss due to atmospheric drag. A point mass representation of the Earth's …

An Analog Computer Simulation Of The Flapping Of A Helicopter Hinged Main Rotor Blade, Edward Charles Robinson

Masters Theses

"An analog computer simulation was performed on the Systron Donner SD 40/80 electronic differential analyzer consisting of one panel (SD 40) less three modules augmented by three digital logic modules for iterative operation. The flapping equation was solved in continuous iteration for various values of blade mass and the resultant blade flapping magnitudes and harmonic coefficients were compared in computer plots of the blade tip path plane. A flap compensator was added and the result plotted. Various aerodynamic parameters of the flapping equation solution were plotted"--Abstract, page ii.

Initial Operation And Calibration Of The Umr Supersonic Axisymmetric Wind Tunnel, James Riley Murphy

Masters Theses

"Initial testing and a preliminary calibration were conducted in the UMR supersonic variable Mach number axisymmetric blowdown wind tunnel facility. During initial operations problems were encountered with control valve seat failure, control valve response and stability, and automatic operation. After having brittle fracture failures with seats made of nylon, Teflon and Telfon-copper composite, a copper seat was found to perform satisfactorily with minimal valve leakage. Control valve response and stability were greatly influenced by the setting of the needle valve located between the total pressure probe and the controller. The needle valve setting was observed to depend upon the stagnation …

Turbulent Structure In The Wake Of Sphere, Darrell W. Pepper

Masters Theses

"The study of turbulent wakes is considered necessary to understand the droplet behavior associated with the collision coalescence phenomena in atmospheric clouds. The Vertical Atmospheric Wind Tunnel enables experiments dealing with this droplet behavior to be analyzed. The experiments conducted in the UMR Vertical Atmospheric Wind Tunnel consist of two parts: one is the investigation of the flow field characteristics in the test section of the wind tunnel; the other is the measurement of the turbulent structure in the wake of a sphere. The test section is rectangular in design and has a cross-sectional area of 36 square inches (6 …

The Numerical Solution Of Two-Dimensional Fluid Flow Problems, E. David Spong

Masters Theses

"A numerical solution method is developed for the solution of two-dimensional, irrotational and compressible fluid flow problems. The partial differential equation, in terms of the velocity potential, describing the flow is replaced by finite difference equations and the resulting matrix is solved by Gaussian elimination. The method is successfully applied to two subsonic flow problems: a 7.5⁰ wedge and a 6⁰ wedge inlet. The method becomes invalid, as expected, with the appearance of sonic velocity in the flow field. An investigation of the definition of the singularities is made. This indicates that the best agreement with the experimental results for …

Collision And Pursuit Course Terminal Closures For Spacecraft To Satellite Rendezvous, John Anthony Campbell

Masters Theses

"Collision and pursuit course closure maneuvers were studied for correcting position and velocity errors in the terminal phase of spacecraft to satellite rendezvous.

Minimum values of the ratio of initial range to velocity necessary to achieve rendezvous were determined for collision closures as a function of the initial line of sight. The time and velocity increment required for rendezvous were computed as a function of initial conditions.

Pursuit closure maneuvers were analyzed and time and velocity increments defined as a function of initial range, closing velocity, line of sight angle and angular velocity.

The velocity increments required were significantly higher …

An Investigation Of The Need To Correlate Academic Subject Areas With Industrial Arts, Ernest James Boedcher

Graduate Student Research Papers

This study was initiated as a result of a need that became apparent in two industrial arts seminars at Central Washington State College. Studies reveal that industrial arts teachers use principles, laws, and applications of mathematics and science daily, but these are seldom recognized and made meaningful to the students. As a result of this study industrial arts teachers may see a way to use this material to initiate similar situations in their teaching.

Wind-Tunnel Measurements Of The Aerodynamic Damping And Oscillatory Stability In Pitch Of A Sphere At Mach Numbers From 0.20 To 4.63, Robert Ashworth Kilgore

Dissertations, Theses, and Masters Projects

No abstract provided.

On The Problem Of Radio Signal Attenuation During Hypervelocity Reentry, David Joseph Romeo

Dissertations, Theses, and Masters Projects

No abstract provided.

Diurnal And Seasonal Variations Of Satellite Scintillation, John David Martin

Dissertations, Theses, and Masters Projects

No abstract provided.

A Theory Of Space Probe Entry Near The Low-Meteoric Velocity Limit, Frederick Cyril Grant

Dissertations, Theses, and Masters Projects

No abstract provided.