Aerospace Engineering Commons^™

Analysis Of Aerothermodynamic Environment Of A Titan Aerocapture Vehicle, Hsing Chow

Mechanical & Aerospace Engineering Theses & Dissertations

The extent of convective and rad1ative heating for a Titan entry vehicle is invest1gated. The flow in the shock layer is assumed to be axisymmtric, steady, viscous, and compressible. It is further assumed that the gas is in chemical and local thermodynamic equilibrium and tangent slab approximation is used for the rad1ative transport. The effect of slip boundary conditions on the body surface and at the shock wave are included in the analysis of high altitude entry conditions. The implicit finite difference technique is used to .solve the viscous shock layer equations for a 45-degree sphere cone at zero angle …

Low Speed Handling Characteristics Of A Supersonic Transport By Eigenstructure Assignment, Michael Peter Lazar

Mechanical & Aerospace Engineering Theses & Dissertations

A synthesis procedure, based upon optimal regulator theory and eigenvalue/eigenvector assignment technique, was used in the design of a low-speed lateral control system for the SCAT-15F supersonic transport. Emphasis was placed on reducing the lateral acceleration at the pilot's station. Control laws were designed to make the aircraft handling characteristics acceptable with the exception of the lateral acceleration. It was found that a compromise between the roll performance requirements and the peak lateral acceleration requirement is needed for a successful SCAT-15F design.

Atmospheric Measurements Of Ccn In The Supersaturation Range 0.013-0.681%., Darryl J. Alofs, T. H. Liu

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Concentrations of Cloud Condensation Nuclei in the Atmosphere Were Measured at Rolla, Missouri, Near Ground Level. a Total of 432 Spectra Were Measured over a 10-Month Period. No Consistent Seasonal or Diurnal Pattern Was Observed. Possible Implications for Fogs and Stratus Clouds and for Nuclei Chemical Composition Are Discussed.-From Authorscloud Condensation Nuclei Rolla Missouri Fogs

Experimental Study Of Delta Wing Leading-Edge Devices For Drag Reduction At High Lift, Thomas Dwight Johnson Jr.

Mechanical & Aerospace Engineering Theses & Dissertations

Future fighter aircraft requirements specify efficient supersonic cruise and high-g maneuverability at high lift. The slender delta wing meets the first requirement but has large lift induced drag increments at high lift. One method to alleviate the drag is to control the flow at the wing leading edge (LE) by means of small LE devices, so as to maintain locally attached flow to higher angles of attack and thus increase the level of aerodynamic thrust.

The devices selected for evaluation were the fence, slot, pylon-type vortex generator (VG), and sharp leading-edge extension (SLEE). These devices were tested on a 60° …

A Nonlinear Hybrid Vortex Method For Wings Having Side-Edge Separations, Li-Chuan Chu

Mechanical & Aerospace Engineering Theses & Dissertations

A Nonlinear Hybrid-Vortex method (NHV-method) has been developed for predicting the aerodynamic characteristics of wings exhibiting side-edge separations. The present method is a coupline between vortex-panel and vortex-line methods. In the near-field calculations, vortex panels are used while in the far-field calculat1ons, vortex lines are used.

The wing and its free-shear layers are divided into planar quadrilateral panels having first-order vorticity distribution. The aerodynamic boundary conditions and continuity of the vorticity distributions are imposed at certain nodal points on the panels. An iterative technique is used to satisfy these conditions to obtain the vorticity distributions and the wake shape as …

Continuous Digital Simulation Of The Second-Order Slowly Varying Wave Drift Force, Bohdan W. Oppenheim, P. A. Wilson

Systems Engineering Faculty Works

A discussion is given on practical aspects of digital representation in time of the slowly oscillatory second-order wave drift force from a known force spectrum. The emphasis is placed on the computational efficiency and on the suitability of the simulation to a numerical integration of an equation of motion using a variable integration step size, where the force acts as the excitation of motion. The effect of approximating the original spectrum by a white spectrum is discussed. A sensitivity analysis is made to the range of frequencies of the spectra. The force time record is obtained by first generating at …

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 …

Combined Heat And Lass Transfer In Mixed Confection Ower A Horizontal Flat Plate, T. S. Chen, F. A. Strobel

Mechanical and Aerospace Engineering Faculty Research & Creative Works

The combined effects of buoyancy forces from thermal and species diffusion on the heat and mass transfer characteristics are analyzed for laminar boundary layer flow over a horizontal flat plate. The analysis is restricted to processes with low concentration levels such that the interfacial velocities due to mass diffusion and the diffusion-thermo/thermo-diffusion effects can be neglected. Numerical results for friction factor, Nusselt number, and Sherwood number are presented for gases having a Prandtl number of 0.7, with Schmidt numbers ranging from 0.6 to 2.0. In general, it is found that, for the thermally assisting flow, the surface heat and mass …

Rubber Covered Rolls-The Nonlinear Elastic Problem, R. C. Batra

Mechanical and Aerospace Engineering Faculty Research & Creative Works

The problem of the indentation of a rubberlike layer bonded to a rigid cylinder and indented by another rigid cylinder is analyzed. The rubberlike layer is assumed to be made of a homogeneous Mooncy-Rivlin material. The materially and geometrically nonlinear problem is solved by using the finite-element code developed by the author. Results computed and presented graphically include the pressure profile at the contact surface, stress distribution at the bond surface and the deformed shape of the indented surface. © 1980 by ASME.

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 …

Demonstration Of Low Btu Gasification Using The Grow Facility, V. J. Flanigan, Y. Omurtag

UMR-DNR Conference on Energy

No abstract provided.

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 …

Nucleation Experiments With Monodisperse Nacl Aerosols., Darryl J. Alofs, M. B. Trueblood, D. R. White, V. L. Behr

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Nucleation Experiments with Monodisperse NaCl Aerosols Showed Good Agreement with the Kohler Theory Relating the Critical Super-Saturation S//c to the Dry Size. Aerosols Produced by Condensing NaCl Showed the Same S//c as Those Produced by Evaporating Aqueous NaCl Solution Droplets. This Indicates that If There is an Energy Barrier in Going from a Dry NaCl Particle to a Solution Droplet, This Energy Barrier is Small. the Fact that the Evaporation Aerosol Particles Are Cubical Crystals and the Condensation Aerosols Are Amorphous Spheres is Shown to Make No Difference in the Nucleation Threshold. the Investigation Also Gives Insights into the Performance …

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, …

An Experimental Investigation Of A Turbulent Boundary Layer With Suction Through Closely Spaced Streamwise Slots, Stephen P. Wilkinson

Mechanical & Aerospace Engineering Theses & Dissertations

The object of this research was to experimentally evaluate a suction surface for use with incompressible turbulent boundary layers. The surface consisted of an array of closely spaced slots aligned in the direction of the free stream flow. Direct drag and mean boundary layer velocity profile measurements showed that the slotted surface had nominally the same suction characteristics as the porous surface.

Testing Of Solar Collectors By A Standard Method, Harry J. Sauer Jr., Bassem F. Armaly

UMR-MEC Conference on Energy / UMR-DNR Conference on Energy

A description of the recently adopted standard for testing solar collectors "ASHRAE STANDARD 93-77, METHOD OF TESTING SOLAR COLLECTORS BASED ON THERMAL PERFORMANCE" is presented. Results from the standard could be used to simulate the transient performance of an installed solar system.

Performance Of A Dual-Range Cloud Nucleus Counter., Darryl J. Alofs

Mechanical and Aerospace Engineering Faculty Research & Creative Works

An Instrument for Measuring the Concentrations of Cloud Condensation Nuclei as a Function of Nucleus Critical Supersaturation (S//c) is Described. in the Range 0. 1% Less Than Equivalent to S//c Less Than Equivalent to 0. 1%, the Instrument is Operated as a Vertical Flow Thermal Diffusion Chamber. in the Range of 0. 016% Less Than Equivalent to S//c Less Than Equivalent to 0. 1%, the Chamber is Operated at 100% Humidity, and the Equilibrium Radii of the Nuclei Are Measured with an Optical Counter. This Paper Presents a Large Body of Data Taken in the Laboratory to Evaluate the Performance …

A Small Horizontal Axis Wind Turbine Feeding Power Into The Utility Grid, G. C. Thomann, M. Jong, M. H. Snyder

UMR-MEC Conference on Energy / UMR-DNR Conference on Energy

A small horizontal axis wind turbine, with about a 2 kW power output, was constructed to convert wind energy into AC power to be fed into the utility grid. The machine is intended to model operation of the larger wind generators now being built. The variable pitch rotor is 18 ft in diameter and has a GA(W)-1 blade airfoil. The rotor is fabricated from sitka spruce mounted on a commercial propeller/hub system. Rotor speeds of from 75 to 150 rpm are used in operation. A chain drive and helical gear drive system steps up rotor speed to 1800 - 3600 …

Airfoil Data For Use Of Wind Turbine Designers, Melvin H. Snyder

UMR-MEC Conference on Energy / UMR-DNR Conference on Energy

This paper reviews design procedures for wind-axis turbine rotors. An "on-design" routine for rotor blade design is presented as well as an "off-design" performance calculation program. Resulting from this review are analyses of desirable characteristics of airfoil sections and of types of data which rotor designers need. Included in the paper are airfoil characteristics for candidate blade sections including 360 degree data for GA(W)-1 and GA(W)-2 airfoils.

Low Head Power Generation With Bulb Turbines, J. L. Carson, R. S. Samuelson

UMR-MEC Conference on Energy / UMR-DNR Conference on Energy

Because of uncertainties, delays, and high costs associated with alternative electric energy sources, many agencies responsible for generation of electrical power are investigating means of replacing or supplementing their existing hydroelectric facilities. In the head range between 10 and 60 feet, the bulb-type generating unit, in which the generator is enclosed in a metal capsule within the water passage, has many advantages, including higher efficiency and lower cost, over other types of turbines. Two of the municipalities in the United States which have recently conducted feasibility studies for installing bulb turbines in their systems are the City of Idaho Falls, …

Static Temperature Measurements In Supersonic Flow Using Lasar Raman Spectroscopy, Paul A. Nystrom

Mechanical & Aerospace Engineering Theses & Dissertations

Laser Raman spectroscopy is a nonintrusive technique which can generate mean static temperature (MST) data within flow fields. By ratioing two simultaneously gathered portions of the Raman scattered spectrum, absolute intensity measurements were not needed. This method was applied to a supersonic cold air jet, where the NST ranged from 160'K to 300'K. Accurate measurements were not realized due to the presence of flow contaminates, especially water vapor.

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 …

The Sun's Wind, Alexei Leonov

Articles

This book is on display here for educational purposes only.

Unless stated otherwise within this repository collection, all materials are shared under the following Creative Commons license: [Creative Commons Attribution-NonCommercial 4.0 International License].

Written and illustrated in 1977 by Soviet cosmonaut Alexei Leonov.
Published by Progress Publishers in Moscow

Mixed Convection Across A Horizontal Cylinder With Uniform Surface Heat Flux, A. Mucoglu, T. S. Chen

Mechanical and Aerospace Engineering Faculty Research & Creative Works

No abstract provided.

Optimal Cantilever Dynamic Vibration Absorbers, R. G. Jacquot, J. Earl Foster

Mechanical and Aerospace Engineering Faculty Research & Creative Works

This work considers the use of a double-ended cantilever beam as a distributed parameter dynamic vibration absorber applied to a single-degree-of-freedom system in the presence of sinusoidal forces. The problem is analyzed exactly and by an energy approach using a single mode approximation for the cantilever beam. The results for both techniques compare favorably and damping is introduced in the form of a complex beam modulus. Optimal tuning and optimal damping parameters are found for a given ratio of absorber mass to main mass. © 1977 by ASME.

Studies Of Vibrational Surface Modes In Ionic Crystals. I. Detailed Shell-Model Studies For The Unrelaxed (001) Face Of Seven Crystals Having The Rocksalt Structure, T. S. Chen, F. W. De Wette, G. P. Alldredge

Mechanical and Aerospace Engineering Faculty Research & Creative Works

We present a comprehensive, unified account of the lattice dynamics of unrelaxed (001) faces of seven crystals having the rock salt structure, three of which have an absolute gap between the acoustical and optical bulk bands (RbF, RbCl, and NaI) and four of which have overlap between these bulk bands (NaF, NaCl, LiF, and MgO). The results are obtained from calculations of the normal modes of a thin crystal film in which the ionic interactions are described by the rigid-shell model. An outline of the formulation of the shell model for the film is given, and the rapid convergence of …

A Closed-Form Solution For The Radiosity At The Edge Of A Rectangular Cavity, Alfred L. Crosbie

Mechanical and Aerospace Engineering Faculty Research & Creative Works

No abstract provided.

Predicting Natural Frequencies Of A Hydrodynamically Lubricated Journal Bearing With Constant Oil Supply Pressure, D. C. Edwards, N. Khorzad, Charles L. Edwards

Mechanical and Aerospace Engineering Faculty Research & Creative Works

The analytical and experimental investigations reported here deal with the natural frequencies and system behavior of a full journal bearing subjected to a small sinusoidal load superimposed on a large unidirectional static load. The analysis, verified by experimentation, shows that the bearing can be regarded as two independent second-order systems acting perpendicular to each other. The variable coefficients of the equations of motion cause the bearing to behave as an underdamped system for low values of static eccentricity ratio to, and as an overdamped system for intermediate values of to. The bearing tends to be unstable above a particular to. …

Development Of Helicopter Flight Path Models, Alfred Fermelia, Donald A. Gyorog, V. J. Flanigan

Mechanical and Aerospace Engineering Faculty Research & Creative Works

The objective of this paper is to present general techniques for simulating helicopter flight trajectory response. During flight the pilot manipulates the controls either to trim the helicopter for steady flight by balancing the external forces and moments or to produce a desired maneuver by controlling the unbalance of these forces and moments. Discussions of the physical phenomena involved with the aerodynamics of the rotors and fuselage are given in [1] through [3]. The simulated control function will be composed forward-aft cyclic, lateral cyclic, pedal, and collective. This control will be represented by the vector