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Articles 421 - 441 of 441
Full-Text Articles in Aerospace Engineering
Reply To The Comments Of H. M. Princen [2], Robert A. Medrow, B. T. Chao
Reply To The Comments Of H. M. Princen [2], Robert A. Medrow, B. T. Chao
Mechanical and Aerospace Engineering Faculty Research & Creative Works
No abstract provided.
Forming Of 7075-T6 Aluminum In High Pressure Environments, Richard L. Pendleton, Robert L. Davis
Forming Of 7075-T6 Aluminum In High Pressure Environments, Richard L. Pendleton, Robert L. Davis
Mechanical and Aerospace Engineering Faculty Research & Creative Works
Plates of 7075-T6 Aluminum have been folded along a major axis in pressure environments of atmospheric, 20,000 psi, and 40,000 psi. A finite element computer program is used to determine the stress state in the plates at various loads. Tension and compression tests conducted in pressure environments up to 70,000 psi were used to construct models using effective stress, effective strain, and pressure as parameters to predict the behavior of the material under various stress conditions. A prediction of the occurrence of fracture in the folded plate was possible using the computer results and the pressure dependent model. As better …
A Strain Energy Comparison Of Discrete Modeling For Vibrating Continuous Systems, S. K. Tolani, Richard Dale Rocke
A Strain Energy Comparison Of Discrete Modeling For Vibrating Continuous Systems, S. K. Tolani, Richard Dale Rocke
Mechanical and Aerospace Engineering Faculty Research & Creative Works
Lumped parameter models commonly used to describe continuous one-dimensional and Bernoulli-Elder beam vibration problems have been compared on the basis of maximum system, strain energy. The consistent mass matrix approach has been included in the comparison. Standard matrix techniques have been employed to mathematically obtain desired solutions. Closed form solutions and solutions via the models to Ike system strain energy were obtained for all systems in three dynamic states: Free vibrations, constant base acceleration, and half sine base acceleration. Behavior of the strain energy errors, in general, were found to be similar to those of the frequency root errors. © …
Magnetohydrodynamic Stability Of The Developing Laminar Flow In A Parallel-Plate Channel, T. S. Chen, T. E. Eaton
Magnetohydrodynamic Stability Of The Developing Laminar Flow In A Parallel-Plate Channel, T. S. Chen, T. E. Eaton
Mechanical and Aerospace Engineering Faculty Research & Creative Works
Linear stability of the developing laminar flow of an electrically conducting, incompressible fluid in a parallel-plate channel under a transverse magnetic field is investigated. The case of small magnetic Reynolds numbers is treated. The developing flows whose stability characteristics are studied correspond to those induced by a uniform and a parabolic velocity distribution at the channel inlet. The stability of the fully developed Hartmann flow is also reexamined. Neutral stability curves and axial variations of the critical Reynolds number are presented for a range of Hartmann numbers between 0 and 4. It is found that for Hartmann numbers larger than …
The Axial Contact Of Finite Elastic Cylinders With Application To Thermal Contact Resistance, Ross Orlo Mcnary
The Axial Contact Of Finite Elastic Cylinders With Application To Thermal Contact Resistance, Ross Orlo Mcnary
Mechanical and Aerospace Engineering Faculty Research & Creative Works
Predictions of the macroscopic thermal contact resistance have been severely restricted because the macroscopic contact area between finite members could not be determined. A new method of solution to this contact problem in elasticity is developed which is applicable to a wide variety of geometries and boundary conditions. A physical lumped-parameter model is employed from which the finite difference equations in terms of displacement are derived. Calculations using this method indicate that large errors in the prediction of the thermal contact resistance can result if solutions for bodies of infinite extent are employed for finite regions of interest. Especially large …
Floating Bubble Configurations, Robert A. Medrow, B. T. Chao
Floating Bubble Configurations, Robert A. Medrow, B. T. Chao
Mechanical and Aerospace Engineering Faculty Research & Creative Works
The configurations of bubbles floating at a vapor-liquid interface are investigated both analytically and experimentally. The differential equations governing the shape of a single bubble at rest in a liquid of infinite extent are deduced under the assumption of zero dome thickness, uniform surface tension, and equal gas densities within the bubble and above the interface. These equations show that nondimensional bubble shapes depend upon the value of a single parameter. An analytical solution, valid for small bubbles, is developed and shown to be in good agreement with the general numerical solution. Good agreement with theory is demonstrated for floating …
Cylindrical Couette Flow Experiments In The Transition Regime, Darryl J. Alofs, George S. Springer
Cylindrical Couette Flow Experiments In The Transition Regime, Darryl J. Alofs, George S. Springer
Mechanical and Aerospace Engineering Faculty Research & Creative Works
Density Distributions Were Measured in Rarefied Argon Contained between Two Concentric Cylinders, the Inner One Rotating, the Outer One Stationary. the Experiments Were Performed with a Mach Number Near Unity, based on the Surface Speed and Surface Temperature of the Rotating Cylinder. Particular Attention Was Focused on Obtaining Data in the Slip and Transition Regimes Where the Knudsen Number, Defined as the Ratio of the Mean Free Path to the Gap Size between the Cylinders, Varied from 0.04 to 1.07. the Density Distributions Were Measured by Observing the Gas Luminescence Induced by the Passage of a Narrow Beam of High …
An Approximate Model For The Static Operation Of A Fluidic Amplifier Employing Axisymmetric Jets, Richard T. Johnson
An Approximate Model For The Static Operation Of A Fluidic Amplifier Employing Axisymmetric Jets, Richard T. Johnson
Mechanical and Aerospace Engineering Faculty Research & Creative Works
An approximate mathematical model for the static, no-load (blocked receiver) operation of a fluidic amplifier employing axisymmetric jets is developed. The amplifier is similar in concept to the three-terminal modulator developed by the Johnson Service Co. The approach used in developing the model assumes that the complex flow phenomena can be represented by the combination of several elementary flow problems. The model employs the concept of an equivalent power nozzle in describing downstream flow with a control signal present. Experimental results are presented to justify assumptions and evaluate parameters. © 1971 by ASME.
Charges On Jet Drops Produced By Bursting Bubbles, Robert A. Medrow, B. T. Chao
Charges On Jet Drops Produced By Bursting Bubbles, Robert A. Medrow, B. T. Chao
Mechanical and Aerospace Engineering Faculty Research & Creative Works
The sizes and charges of jet drops produced by bursting air bubbles are examined experimentally. The variation in charge for bubble lifetimes of up to 200 sec in NaCl and KCl solutions is reported. Jet drops refer to drops produced by a jet rising from a cavity left in a liquid surface by a bursting bubble; bubble lifetime is the interval during which a bubble is in motion between generation and rupture. With other variables held constant, drop charge shows a characteristic variation of a rise to a maximum followed by a decrease to an asymptotic value, as bubble lifetime …
Density Distribution Measurements In Rarefied Gases Contained Between Parallel Plates At High Temperature Differences, Darryl J. Alofs, Richard C. Flagan, George S. Springer
Density Distribution Measurements In Rarefied Gases Contained Between Parallel Plates At High Temperature Differences, Darryl J. Alofs, Richard C. Flagan, George S. Springer
Mechanical and Aerospace Engineering Faculty Research & Creative Works
Density Distributions Were Experimentally Determined in Rarefied Gases at Rest Contained between Two Parallel Plates Maintained at Widely Different Temperatures. the Temperatures of the Hot and Cold Plates Were ∼79°K and ∼294°K, Respectively, Resulting in a Temperature Ratio of About 4:1. Both Helium and Nitrogen Were Used as Test Gases. Particular Attention Was Focused on Obtaining Data in the Temperature Jump and Transition Regimes. the Gas Densities Were Measured by Observing the Luminescence Produced by a High-Energy Electron Beam Traversed between the Plates. in Addition to the Density Measurements, Heat Transfer Measurements Were Also Made in Order to Estimate the …
Heat Transfer From An Oscillating Horizontal Wire, Bassem F. Armaly, D. H. Madsen
Heat Transfer From An Oscillating Horizontal Wire, Bassem F. Armaly, D. H. Madsen
Mechanical and Aerospace Engineering Faculty Research & Creative Works
The effect of vibration on heat transfer by natural convection has been investigated experimentally using a thin wire, 0.010 in. in diameter, and air as a convection medium. Horizontal reciprocating motion of varying amplitudes, peak-to-peak values of 0-2.655 in., and frequencies, 0-20 cps, was applied to an electrically heated horizontal wire. The average wire velocity (frequency times total path length traveled per cycle by the wire) was used to correlate and predict the experimental results. © 1971 by ASME.
Rotating Cylinder Apparatus For Rarefied Gas Flow Studies, Darryl J. Alofs, George S. Springer
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
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.
Radiative Heat Transfer Analysis From A Heated Airport Runway To Fog, Gordon L. Scofield, Tom J. Love
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 …
On The Longitudinal Impact Of Two, Thin, Viscoelastic Rods, A. G. Behring, R. B. Oetting
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.
Stability Of Asymmetric Hydrodynamically Developing Channel Flows, T. S. Chen, E. M. Sparrow
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.
Structure Of Shock Waves With Nonequilibrium Radiation And Ionization, Harlan F. Nelson, R. Goulard
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. …
Methods For Evaluating The Performance Of Small Acoustic Filters, William S. Gatley, Raymond Cohen
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 …
Film Boiling Heat Transfer From An Oscillating Sphere, L. G. Rhea, R. G. Nevins
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 …
Free-Convection Heat Transfer From An Inclined Heated Flat Plate In Air, S. C. Yung, R. B. Oetting
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.
Mutually Dependent Heat And Mass Transfer In Laminar Duct Flow, E. M. Sparrow, T. S. Chen
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 …