Aerospace Engineering Commons^™

Rotating Cylinder Apparatus For Rarefied Gas Flow Studies, Darryl J. Alofs, George S. Springer

Mechanical and Aerospace Engineering Faculty Research & Creative Works

A Rotating Cylinder Type Apparatus is Described, Suitable for Determining Drag in Cylindrical Couette Flow of Rarefied Gases, and for Evaluating Tangential Momentum Accommodation Coefficients at Gas-Solid Boundaries. the Apparatus is Equipped with a Damping Device using Diffusion Pump Oil for Eliminating Undesirable Oscillations in the System. Tangential Momentum Accommodation Coefficients of Argon on Aluminum Were Determined with an Accuracy of ±2.5%. the Results Obtained Indicate that the Apparatus May Be Used over a Wide Pressure Range, Corresponding to Free Molecule and Continuum Flow Conditions. © 1970 the American Institute of Physics.

Rotating Cylinder Apparatus For Rarefied Gas Flow Studies, Darryl J. Alofs, George S. Springer

Mechanical and Aerospace Engineering Faculty Research & Creative Works

A rotating cylinder type apparatus is described, suitable for determining drag in cylindrical Couette flow of rarefied gases, and for evaluating tangential momentum accommodation coefficients at gas-solid boundaries. The apparatus is equipped with a damping device using diffusion pump oil for eliminating undesirable oscillations in the system. Tangential momentum accommodation coefficients of argon on aluminum were determined with an accuracy of ± 2.5%. The results obtained indicate that the apparatus may be used over a wide pressure range, corresponding to free molecule and continuum flow conditions.

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 …

Radiative Heat Transfer Analysis From A Heated Airport Runway To Fog, Gordon L. Scofield, Tom J. Love

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Radiative heat transfer between a plane source and an aerosol is investigated through the Monte Carlo method. Thermal energy is transferred from a long rectangular source to monodisperse natural fog models. The analysis is only for radiative transport and does not include convection which would be coupled in a complete analysis. Direct energy transfer to the droplets of the aerosol is investigated for values of extinction coefficient of 10 km-1 and 80 km-1, absorption coefficient to extinction coefficient ratios of 0·4 and 0·5, and scattering functions of the strong forward and isotropic types. Monochromatic radiation at a wave length of …

Stability Of Asymmetric Hydrodynamically Developing Channel Flows, T. S. Chen, E. M. Sparrow

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Linear stability is studied for developing channel flows induced by asymmetric velocity profiles at the inlet. Neutral stability curves and axial variations of the critical Reynolds number are presented, showing greater stability for more skewed inlet profiles.

On The Longitudinal Impact Of Two, Thin, Viscoelastic Rods, A. G. Behring, R. B. Oetting

Mechanical and Aerospace Engineering Faculty Research & Creative Works

A one-dimensional representation of the distribution of stress and strain resulting from the longitudinal impact of two elastic rods is developed. A form of the "correspondence principle" is then used to obtain series solutions for stress and strain distributions resulting from the longitudinal impact of two rods of a "Maxwell material." Results of the viscoelastic solutions, obtained by use of nondimensional variables, are presented graphically. © 1970 by ASME.

Film Boiling Heat Transfer From An Oscillating Sphere, L. G. Rhea, R. G. Nevins

Mechanical and Aerospace Engineering Faculty Research & Creative Works

An experimental investigation has been undertaken to determine the effect of oscillation of the heat transfer surface on turbulent film boiling heat transfer. A transient technique was used to calculate the heat flux from copper spheres of 1 in., 3/4 in., and 1/2 in. dia. In all tests, saturated liquid nitrogen at atmospheric pressure was used as the boiling fluid. The data obtained were found to be in good agreement with published theory at zero frequency. The range of frequencies studied was from zero to approximately 12 cps at peak-to-peak amplitudes of 2 in. and 1 in., i.e., at amplitude-to-diameter …

Structure Of Shock Waves With Nonequilibrium Radiation And Ionization, Harlan F. Nelson, R. Goulard

Mechanical and Aerospace Engineering Faculty Research & Creative Works

The investigations of this study are concerned with: (1) the physical processes that occur in the precursor and in the nonequilibrium region behind a strong shock wave during its approach to equilibrium in an argon like gas; (2) the influence of different atom-atom collisional rates in the relaxation region on the precursor; and (3) the cause of precursor ionization, which in this study has been assumed to be the photoionization of both the ground and excited states. The argon like gas is regarded as a combination of two gases: one consisting of electrons and the other of atoms and ions. …

Free-Convection Heat Transfer From An Inclined Heated Flat Plate In Air, S. C. Yung, R. B. Oetting

Mechanical and Aerospace Engineering Faculty Research & Creative Works

No abstract provided.

Methods For Evaluating The Performance Of Small Acoustic Filters, William S. Gatley, Raymond Cohen

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Experimental methods are needed for determining the characteristics of small acoustic filters used in systems with pulsating gas flows. These characteristics could then be used to predict the performance of proposed filter designs in a particular system, according to plane wave acoustic theory. Dependence on trial-and-error experimentation in solving noise control problems would thus be minimized. A literature survey revealed only a few earlier attempts to evaluate the acoustic performance of small filters and filter elements. Three methods for determining reflection and transmission factors are described, evaluated, and compared. A method employing a standing wave tube of unique design is …

Mutually Dependent Heat And Mass Transfer In Laminar Duct Flow, E. M. Sparrow, T. S. Chen

Mechanical and Aerospace Engineering Faculty Research & Creative Works

An analysis is performed of the strongly coupled heat and mass transfer processes which result from sublimation of mass from the walls of a duct into a flowing gas, the latent heat being provided solely by convective transfer from the gas. The flow is assumed to be laminar and hydrodynamically developed. Results are given for the stream ward variations of the bulk and wall temperatures and mass fractions, of the heat and mass transfer rates, and of the local heat transfer coefficient. Representative temperature and mass fraction profiles are also presented. Entrance lengths characterizing the near approach to fully developed …

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 …