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in subjects: "boundary layers"

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1964 Project Springfield studies. Research Report 2. [Stratospheric-tropospheric exchange of fallout particles and subsequent rainout of radioactive particles by precipitation systems]

The analysis of the data for a storm on April 4, 1964, showed that in spite of all efforts to obtain a dynamically and internally consistent three-dimensional analysis of conventional wind, pressure, and temperature data, there remain ambiguities of 50 to 100 miles in the horizontal location of the boundaries of the stratospheric air. Missing wind data and temperature errors, though not disastrous in routine meteorological analysis, can seriously affect the potential vorticity computations for … more

Date: October 1, 1975

Creator: Feteris, P. J.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Accelerator-based plasma-wall interaction studies on the TEXTOR tokamak

Deposition probes are commonly used to determine plasma edge characteristics in tokamaks. Such probes are frequently analyzed using accelerator-based techniques and can yield information on impurity fluxes, hydrogen fluxes and energies, and surface erosion rates in the plasma edge. Several types of deposition probes have been employed to investigate the plasma edge region of the TEXTOR tokamak in Juelich, FRG. TEXTOR is a moderate size tokamak (major radius = 1.75 m) that is capable of 2 to 3 s… more

Date: September 1, 1984

Creator: Zuhr, R.A.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Acoustic detection of momentum transfer during the abrupt transition from a laminar to a turbulent atmospheric boundary layer

Acoustic sounder measurements of a vertical profile of the abrupt transition from a laminar to a turbulent atmospheric boundary layer were compared with meteorological measurements made at 10 m and 137 m on an instrumented tower. Sounder data show that conditions necessary for onset of the momentum burst phenomenon exist sometime during a clear afternoon when heat flux changes sign and the planetary surface cools. Under these conditions, the lowest part of the atmospheric boundary layer becomes… more

Date: January 1, 1975

Creator: Schubert, J. F.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Active tokamak limiters; symmetrizing the edge plasma

The surface layers of tokamak plasmas are strongly unstable to low frequency oscillations. The limiter, by imposing a non-axisymmetric state in the plasma scrape-off layer, may be the source of the free energy driving the instabilities. An active, two-faced sandwich limiter is proposed to symmetrize the scrape-off layer, thereby minimizing the mismatch between the inner and outer tokamak states.

Date: February 1, 1981

Creator: Motley, R. W.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Advances in compressible turbulent mixing

This volume includes some recent additions to original material prepared for the Princeton International Workshop on the Physics of Compressible Turbulent Mixing, held in 1988. Workshop participants were asked to emphasize the physics of the compressible mixing process rather than measurement techniques or computational methods. Actual experimental results and their meaning were given precedence over discussions of new diagnostic developments. Theoretical interpretations and understanding were … more

Date: January 1, 1992

Creator: Dannevik, W. P.; Buckingham, A. C. & Leith, C. E.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Aerodynamic Characteristics of Atmospheric Boundary Layers

Prepared as an account of work by the United States Government, this report talks about the Aerodynamic Characteristics of Atmospheric Boundary Layers.

Date: 1971

Creator: Plate, E. J.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Aerosol Property Comparison Within and Above the ABL at the ARM Program SGP Site

This thesis determines what, if any, measurements of aerosol properties made at the Earth surface are representative of those within the entire air column. Data from the Atmospheric Radiation Measurement site at the Southern Great Plains, the only location in the world where ground-based and in situ airborne measurements are routinely made. Flight legs during the one-year period from March 2000 were categorized as either within or above the atmospheric boundary layer (ABL) by use of an objectiv… more

Date: May 1, 2002

Creator: Delle Monache, L

Item Type: Thesis or Dissertation

Partner: UNT Libraries Government Documents Department

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AEROSOL TRANSPORT IN A CONDENSING-STEAM BOUNDARY LAYER.

No Description Available.

Date: January 1, 1970

Creator: Hales, J.M.; Horst, T.W. & Schwendiman, L.C.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Air flow in a separating laminar boundary layer

Report discussing the speed distribution in a laminar boundary layer on the surface of an elliptic cylinder, of major and minor axes 11.78 and 3.98 inches, respectively, has been determined by means of a hot-wire anemometer. The direction of the impinging air stream was parallel to the major axis. Special attention was given to the region of separation and to the exact location of the point of separation. An approximate method, developed by K. Pohlhausen for computing the speed distribution, th… more

Date: December 1, 1934

Creator: Schubauer, G. B.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Air flow in the boundary layer near a plate

From Summary: "The published data on the distribution of speed near a thin flat plate with sharp leading edge placed parallel to the flow (skin friction plate) are reviewed and the results of some additional measurements are described. The purpose of the experiments was to study the basic phenomena of boundary-layer flow under simple conditions."

Date: March 1936

Creator: Dryden, Hugh L.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Air Flow in the Boundary Layer of an Elliptic Cylinder

From Introduction: "The present investigation was carried out for the purpose of supplementing the earlier work with information on the boundary layer under such conditions of air speed and turbulence that transition occurs and the layer is partly laminar and partly turbulent. In the work reported in reference 1, the air speed was about 12 feet per second, and it was assumed that the boundary layer remained in the laminar condition until after separation because the separation point remained fi… more

Date: August 6, 1938

Creator: Schubauer, G. B.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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ALE3D Simulation and Measurement of Violence in a Fast Cookoff Experiment for LX-10

Fast cookoff is of interest in the areas of fire hazard reduction and the development of directed energy systems for defense. During a fast cookoff (thermal explosion), high heat fluxes cause rapid temperature increases and ignition in thin boundary layers. We are developing ALE3D models to describe the thermal, chemical, and mechanical behavior during the heating, ignition, and explosive phases. The candidate models and numerical strategies are being evaluated using benchmark cookoff experimen… more

Date: May 23, 2006

Creator: McClelland, M. A.; Maienschein, J. L.; Howard, W. M. & Dehaven, M. R.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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ALE3D Simulations of Gap Closure and Surface Ignition for Cookoff Modeling

We are developing ALE3D models to describe the thermal, chemical and mechanical behavior during the heating, ignition and explosive phases of various cookoff phenomena. The candidate models and numerical strategies are being evaluated using benchmark cookoff experiments. ALE3D is a three-dimensional computer code capable of solving the model equations in a coupled fashion through all the phases of the cookoff in a single calculation. For the cookoff experiments, we are interested in representin… more

Date: June 22, 2006

Creator: Howard, W. M.; McClelland, M. A. & Nichols, A. L.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

ALT-I Pump Limiter Experiments

Results from the ALT-I pump limiter experiments in TEXTOR are presented. ALT-I has demonstrated control of the plasma density in a high recycling tokamak by pumping up to 15% of the core efflux. The closed pump limiter designs with restricted entrance geometries to reduce the backflow of neutral gas to the plasma remove over 50% of the ion flux incident on the collection slot. Up to 80% of the entrance ion flux is removed when the edge electron temperature is less than 10 eV and plasma-neutral … more

Date: September 1, 1987

Creator: Goebel, D. M.; Conn, R. W.; Campbell, G. A.; Leung, W. K.; Dippel, K. H.; Finken, K. H. et al.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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An alternative approach to disturbances in boundary layers

By modelling the boundary layer on a flat plate as a piece-wise linear velocity profile it is possible to analyze disturbances in the flow in a systematic manner. The approach is that of an initial-value, boundary-value problem but, unlike classical normal modes employed in stability theory, the solutions here can be obtained in closed form and they are non separable. A specific example is treated where the vertical component of the perturbation velocity is prescribed as a localized pulse initi… more

Date: January 1, 1990

Creator: Easthope, P.F. & Criminale, W.O.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Aluminum-containing intergranular phases in hot-pressed silicon carbide

Aluminum-containing intergranular phases, forming intergranular films and secondary phase particles at triple-junctions in SiC hot-pressed with aluminum, boron, and carbon additions, were studied by transmission electron microscopy. Statistical high-resolution electron microscopy study of intergranular films indicated that a large fraction of the vitreous intergranular films in the s-hot-pressed SiC crystallized during postannealing in argon above 1000 C. However, brief heating to 1900 C indeed… more

Date: January 12, 2003

Creator: Zhang, Xiao Feng & De Jonghe, Lutgard C.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Analysis and Calculation by Integral Methods of Laminar Compressible Boundary-Layer With Heat Transfer and With and Without Pressure Gradient

From Introduction: "The purpose of the present report is to present a comprehensive summary of theoretical investigations of comprehensible laminar boundary layers which have been carried out since 1949 at the Polytechnic Institute of Brooklyn under the sponsorship and with the financial assistance of the National Advisory Committee for Aeronautics. The results of these investigations are contained primarily in references 1 to 7."

Date: April 12, 1955

Creator: Morduchow, Morris

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Analysis of an m = 1 electrostatic barrier scrape-off layer as a technique for reducing and controlling the particle and energy losses on the large major radius edge of tokamak

It is observed in many tokamaks that particle and heat fluxes from the core region are poloidally asymmetric, favoring higher cross field transport on the large major radius edge of the torus. We propose a novel technique that may allow one to control this asymmetric flux into the tokamak boundary plasma. The scheme principally involves the formation of a mobility limited transport layer or 'electrostatic barrier' to inhibit the flow of plasma into the boundary layer at large major radii, forci… more

Date: December 1, 1988

Creator: LaBombard, B. & Conn, R.W.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Analysis of anti z and sigma/sub z/ for near ground releases of tracers in the atmosphere

The Lagrangian similarity theory and statistical theory are used to determine the form of the concentration distribution for a plume in the atmospheric boundary layer. The power of z in the concentration distribution is shown to be a slowly varying function of anti z and z/sub 0/.

Date: January 1, 1978

Creator: Weber, A. H.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Analysis of CASES-99 Lidar and Turbulence Data in Support of Wind Turbine Effects: April 1, 2001 to Januay 31, 2003

The nocturnal low-level jet (LLJ) of the Great Plains of the central United States has been identified as a promising source of high-momentum wind flow for wind energy. The acceleration of the winds after sunset above the surface produces a jet profile in the wind velocity, with maximum speeds that often exceed 10 m s-1 or more at heights near 100 m or more. These high wind speeds are advantageous for wind energy generation. The high speeds aloft, however, also produce a region of high shear be… more

Date: June 1, 2003

Creator: Banta, R. M.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Analysis of Laminar Forced-Convection Heat Transfer in Entrance Region of Flat Rectangular Ducts

From Introduction: "Beyond the position where the boundary layer treatment can no longer be used, curves have been faired to connect the Nusselt number results of the present analysis with those of reference 3, in which a parabolic velocity profile is assumed throughout the entire duct length. So that a comparison could be made with the results of reference 3, the boundary layer analysis was used to study the development of the temperature profile associated with a parabolic velocity profile th… more

Date: January 1955

Creator: Sparrow, E. M.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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An analysis of lift forces on aerosols in a wall bounded turbulent shear flow

This paper describes work that will lead to a better understanding of the role of lift forces in the deposition of aerosols on the walls bounding a turbulent shear flow. After providing some background information about aerosol trajectories that has been obtained from computer simulations, new results for the lift force in the relevant parameter ranges are presented.

Date: December 31, 1992

Creator: Cherukat, P. & McLaughlin, J. B.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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An analysis of lift forces on aerosols in a wall bounded turbulent shear flow

Date: January 1, 1992

Creator: Cherukat, P. & McLaughlin, J. B.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Analysis of particle motions for a class of three-dimensional incompressible laminar boundary layers

From Introduction: "Results obtained in the experimental investigations of secondary flows in turbomachines (refs. 1 to 3) indicate that information concerning three-dimensional laminar boundary-layer behavior can be of practical value in interpreting and correlating measurements of losses in the turbo-machines for design purposes. Reference 4 gives a theoretical analysis of the overturning (more than mainstream turning) of the three-dimensional laminar boundary layer developed on flat or nearl… more

Date: November 1956

Creator: Hansen, Arthur G. & Herzig, Howard Z.

Item Type: Report

Partner: UNT Libraries Government Documents Department