Aerospace Engineering Commons^™

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.

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 …

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 …