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Introduction: Standard aeromedical doctrine dictates that aircrew receiving treatment for depression are grounded during treatment and follow-up observation, generally amounting to at least 1 yr. The Canadian Forces has initiated a program to return selected aircrew being treated for depression to restricted flying duties once stabilized on an approved antidepressant with resolution of depression. The currently approved medications are sertraline (a selective serotonin reuptake inhibitor) and...
Topics: DTIC Archive, DEFENCE RESEARCH AND DEVELOPMENT TORONTO (CANADA), *ANTIDEPRESSANTS, *PSYCHOMOTOR...
A new watch schedule was proposed for use on naval vessels at sea. This schedule requires three watches of 3-, 3- and 2-hour durations by each section of the crew, and provides a continuous period off duty of 10 to 12 hours. This schedule was compared with the present system of four-hour watches separated by eight hours off duty (4 on - 8 off schedule). Comparisons were made during two short cruises and during two long simulated war patrols. The rapidity with which the men adapted to the...
Topics: DTIC Archive, Utterback, Robert A, NAVAL MEDICAL RESEARCH INST BETHESDA MD, *NAVAL PERSONNEL,...
Defense Technical Information Archive
by Defense Technical Information Center
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This technological bibliography provides a systematic accounting of Lighter-Than-Air (LTA) documents. This report should enable rapid review of past and present activities for specific individual applications. Both author and subject indices are included.
Topics: DTIC Archive, Bailey, David B., NAVAL AIR DEVELOPMENT CENTER WARMINSTERPA AIRCRAFT AND CREW SYSTEMS...
Defense Technical Information Archive
by Defense Technical Information Center
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;Contents: Relief of the Barents Sea floor; Surveys of sediments in the Barents Sea; Sediment distribution as related to relief; Stratification of Barents Sea sediments.
Topics: DTIC Archive, Klenova, M V, NAVAL OCEANOGRAPHIC OFFICE NSTL STATION MS, *MARINE GEOLOGY, *ARCTIC...
Defense Technical Information Archive
by Defense Technical Information Center
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Geophysical data taken from March 1957 to September 1960 at the three United States Arctic Ocean drifting stations, ALPHA, T-3 (BRAVO), and CHARLIE, are presented. The tabulations include station positions, ocean depths, oceanographic data, observed gravity and anomalies, and values of some of the magnetic elements. Field procedures are described. A bibliography of reports derived from the scientific programs during this period is included.
Topics: DTIC Archive, Cabaniss, G H, GEOLOGICAL SURVEY RESTON VA, *OCEANOGRAPHIC DATA, *MARINE GEOPHYSICS,...
Defense Technical Information Archive
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The geophysical findings from Fletcher's Ice Island (T-3) for the period mid-1962 to mid-1970 are presented. During this time the ice station traversed the Chukchi Rise, portions of the Alpha Cordillera and Mendeleyev Ridge, and the Chukchi, Mendeleyev, and Canada Plains. The findings, together with pertinent observations from older investigations, support the suggestion of earlier investigators that the Alpha Cordillera is an inactive center of seafloor spreading. Several fractures were...
Topics: DTIC Archive, Hall, John K, LAMONT-DOHERTY GEOLOGICAL OBSERVATORY PALISADES NY, *OCEAN BOTTOM...
The atlas, consisting of two volumes and a separately bound appendix, summarizes available acoustic and environmental data in the Caribbean Sea, Gulf of Mexico and in their Atlantic Ocean approaches between 10 degrees N and 30 degrees N and west of approximately 56 degrees W. This volume includes data on geomagnetic background, subbottom structures, wind, waves, rainfall, and currents.
Topics: DTIC Archive, NAVAL OCEANOGRAPHIC OFFICE NSTL STATION MS, *UNDERWATER SOUND, *MEXICO GULF,...
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Defense Technical Information Archive
by Defense Technical Information Center
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A uniformly-sensitive line hydrophone under development at the Woods Hole Oceanographic Institution has been used to receive broadband seismic reflection signals. The directivity characteristics of an adequately-long continuous line sensor used in a broadband sound field (less than 10 Hz to several kHz) are not easily obtained by arrays of discrete sensors. Discrete element arrays in a sound field of such wide frequency range inevitably develop side lobes of full sensitivity at a number of...
Topics: DTIC Archive, WOODS HOLE OCEANOGRAPHIC INSTITUTION MA, *HYDROPHONES, NETWORKS, DIRECTION FINDING,...
Defense Technical Information Archive
by Defense Technical Information Center
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A summary of the U.S. Navy Underwater Sound Laboratory experimental program to investigate acoustic phenomena in the Arctic is given. As the sound velocity is an increasing function of depth, propagation is characterized by upward refraction and surface reflection. A rough-surface model of the ice cover accounts for both forward and back-scatter. The roughness-wavelength spectrum calculated from reverberation measurements is similar to that for the sea surface although the level is higher....
Topics: DTIC Archive, Mellen, R H, AVCO MARINE ELECTRONICS OFFICE NEW LONDON CT, *UNDERWATER SOUND, *SOUND...
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An expansion of a function initially given in 1deg cells was carried out to degree 360 by using 30'cells whose value was initially assigned to be the value of the 1deg cell in which it fell. The evaluation of point values of the function from the degree 360 expansion revealed spurious patterns attributed to the coefficients from degree 181 to 360. Expansion of the original function in 1deg cells to degree 180 showed no problems in the point evaluation. Mean 1deg values computed from both degree...
Topics: NASA Technical Reports Server (NTRS), FUNCTIONS (MATHEMATICS), GRAVITY ANOMALIES, COEFFICIENTS,...
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NASA Technical Documents
by Norton, F
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As the purpose of the report is to transmit as smoothly and as easily as possible, certain facts and ideas, to the average person likely to read it, it should be written in a full and simple enough manner to be comprehended by the least tutored, and still not be boring to the more learned readers.
Topics: WIND TUNNEL APPARATUS, WIND TUNNELS, MEASURING INSTRUMENTS, WIND TUNNEL TESTS
NASA Technical Documents
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No Abstract Available
Topics: AIRCRAFT HAZARDS, TEMPERATURE EFFECTS, TURBULENT MIXING, FLIGHT HAZARDS, ICE FORMATION,...
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In a previous report, we considered the behavior of the lateral position of vortices as a function of time after vortex formation for Out of Ground Effects (OGE) data for aircraft landing at San Francisco International Airport (SFO). We quantified the spread in lateral position as a function of time and examined how predictable lateral position is under a variety of assumptions. The combination of spread and predictability allowed us to derive probability distribution functions (PDFs) for...
Topics: NASA Technical Reports Server (NTRS), PROBABILITY THEORY, AIRCRAFT WAKES, VORTICES, TRANSPORT...
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Defense Technical Information Archive
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Sea-ice features over that portion of the Polar Pack transited during the 1957 Arctic cruise of the NAUTILUS are discussed and described. Latitudinal and regional comparisons of sea-ice features are made. Data collection methods and instrumentation are described. Recommendations are advanced for future use of the nuclear submarine as a data-collection vehicle. (Author)
Topics: DTIC Archive, Wittmann,Walter I, Ropek,John F, NAVAL OCEANOGRAPHIC OFFICE WASHINGTON D C, *SEA ICE,...
This report describes the first part of a three year study to identify the factors that determine the effectiveness of sonar and target motion analysis (TMA) operators in United States Navy (USN) and UK Royal Navy (RN) submarines. The aim of the programme is to highlight best practice in operator performance in a way that will contribute to training effectiveness. This report describes the progress made by the UK in preparing and conducting a cognitive task analysis of sonar operators.
Topics: DTIC Archive, Hardinge, Neil M, DEFENCE EVALUATION AND RESEARCH AGENCY FARNBOROUGH (UNITED...
Defense Technical Information Archive
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The first phase of this process was the comparison of statistical parameters from analyses carried out by degree of latitude, cognizant of the summer collection period of the 1996 cruise. The second phase was a closer examination of instrument differences and how these might influence current selection criteria in statistical analysis. The final phase has been the consolidation of further data from 1976 and 1991 to permit the comparison of the 1996 dataset with earlier data from similar data...
Topics: DTIC Archive, Wadhams, Peter, SCOTT POLAR RESEARCH INST CAMBRIDGE (UNITED KINGDOM), *SUBMARINES,...
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Defense Technical Information Archive
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A multigrid acceleration technique developed for solving the three dimensional Navier-Stokes equations for subsonic/transonic flows has been extended to supersonic/hypersonic flows. An explicit multistage Runge Kutta type of time-stepping scheme is used as the basic algorithm in conjunction with the multigrid scheme. Solutions have been obtained for a blunt conical frustum at Mach 6 to demonstrate the applicability of the multigrid scheme to high speed flows. Computations have also been...
Topics: DTIC Archive, Vatsa, Veer N, INSTITUTE FOR COMPUTER APPLICATIONS IN SCIENCE AND ENGINEERING HAMPTON...
This report documents the activities, results, conclusions and recommendations of the Magnetohydrodynamics Accelerator Research Into Advanced Hypersonics (MARIAH) Project in which the use of magnetohydrodynamics (MHD) technology is investigated for its applicability to augment hypersonic wind tunnels. The long range objective of this investigation is to advance the development of ground test facilities to support the development of hypervelocity flight vehicles. The MHD accelerator adds kinetic...
Topics: NASA Technical Reports Server (NTRS), MAGNETOHYDRODYNAMICS, HYPERSONICS, PLASMA JET WIND TUNNELS,...
One of the critical technologies of MHD (Magnetohydrodynamics) bypass scramjet propulsion for space launch and cruise vehicles is MHD acceleration. An experiment in a shock tunnel is described in which MHD acceleration is investigated experimentally. The objectives, the methods used and the preliminary results are described in this paper.
Topics: NASA Technical Reports Server (NTRS), SHOCK TUNNELS, SUPERSONIC COMBUSTION RAMJET ENGINES, PLASMA...
The work performed by D. W. Bogdanoff and J.-L. Cambier during the period of 1 Feb. - 31 Oct. 1992 is presented. The following topics are discussed: (1) improvement in the operation of the facility; (2) the wedge model; (3) calibration of the new test section; (4) combustor model; (5) hydrogen fuel system for combustor model; (6) three inch calibration/development tunnel; (7) shock tunnel unsteady flow; (8) pulse detonation wave engine; (9) DCAF flow simulation; (10) high temperature shock...
Topics: NASA Technical Reports Server (NTRS), AERODYNAMICS, COMBUSTION CHAMBERS, COMPUTATIONAL FLUID...
This work predicts whether a retrieval algorithm will usefully determine CO2 concentration from an input spectrum of GOSAT (Greenhouse Gases Observing Satellite). This was done to eliminate needless runtime on atmospheric soundings that would never yield useful results. A space of 50 dimensions was examined for predictive power on the final CO2 results. Retrieval algorithms are frequently expensive to run, and wasted effort defeats requirements and expends needless resources. This algorithm...
Topics: NASA Technical Reports Server (NTRS), GENETIC ALGORITHMS, CARBON DIOXIDE CONCENTRATION, GREENHOUSE...
Defense Technical Information Archive
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Finite element algorithms are presented for the approximate solution of the streamfunction-vorticity equations of steady incompressible viscous flows. Both the linear Stokes and the nonlinear Navier-Stokes equations are considered. The methods discussed require low continuity finite element spaces and do not require any artificial specification of the vorticity at solid boundaries. Particular attention is paid to methods for multiply connected domains and to theoretical and computational...
Topics: DTIC Archive, Gunzburger,M D, CARNEGIE-MELLON UNIV PITTSBURGH PA DEPT OF MATHEMATICS, *ALGORITHMS,...
Defense Technical Information Archive
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A finite element algorithm is described for computing steady and unsteady (oscillatory and transient) transonic flows over thin airfoils by solving directly the unsteady, nonlinear transonic potential equation based on small disturbance theory. The numerical algorithm is developed using the concept of finite elements in conjunction with the least squares method of weighted residuals applied to both space and time. The basic element presently used is a product of an element in space and an...
Topics: DTIC Archive, Chan, S K, LOCKHEED MISSILES AND SPACE CO INC HUNTSVILLE AL HUNTSVILLE ENGINEERING...
A computer program that utilizes the method of integral relations has been developed at the Naval Ship Research and Development Center for use in determining the inviscid transonic flows past lifting airfoils. It allows for a change of entropy across the shock wave and accounts for the presence of an oblique or normal shock at the shock foot. Since many iteractions of the trial and error type are required to obtain the converged flow solution, the program has been adapted for use on the...
Topics: DTIC Archive, Lien, Douglas A., Tai, Tsze C., DAVID W TAYLOR NAVAL SHIP RESEARCH AND DEVELOPMENT...
Defense Technical Information Archive
by Defense Technical Information Center
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A family of two-dimensional potential flows is derived which may describe the interaction of a propulsion jet with the leading edge of a thin wing-in-ground effect at zero angle of attack with a deflected trailing edge flap. Assuming that such flows occur at the leading edge, the static performances of this arrangement-called the Power Augmented Ram Wing-are derived as functions of geometry. A minimum power point is found for given thrust and lift. At this minimum power point, the wing can be...
Topics: DTIC Archive, Gallington, Roger W, DAVID W TAYLOR NAVAL SHIP RESEARCH AND DEVELOPMENT CENTER...
Existing jet mixing theory is reviewed and compared with available experimental results. Simple mixing equations are developed and used to determine the total pressure variation in a two-dimensional jet and the effect of a static pressure change on momentum flux. The effects of free-air entrainment are studied and potential flow solutions given for three particular cases. A method of calculating the lift loss due to vortices arising from viscous mixing is derived and gives good agreement with...
Topics: DTIC Archive, FROST ENGINEERING DEVELOPMENT CORP DENVER CO, *JET MIXING FLOW, EQUATIONS, FLUID...
Defense Technical Information Archive
by Defense Technical Information Center
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This report results from a contract tasking Institute of Theoretical and Applied Mechanics as follows: The contractor will help the CFD group at AFRL to better understand shock-wave/turbulent boundary layer phenomena by providing a comprehensive set of experimental data with emphasis on both quantitative and flow visualization aspects. He will fill-in the gaps which exist in the test matrix both at Mach 4 and 5 He will also expand the range of measurements to include shock structure and skin...
Topics: DTIC Archive, Zheltovodov, Alexander A., RUSSIAN ACADEMY OF SCIENCES NOVOSIBIRSK INST OF...
Three-dimensional glancing-shock/turbulent boundary-layer interaction has been investigated at the Cranfield Institute of Technology in two separate test programmes using a 2.5 x 2.5 inch intermittent tunnel and a 9 x 9 inch continuous tunnel, at a Mach number of approximately 2.5. The experimental results include oil-flow pictures, vapour-screen photographs, surface static pressure distributions, local heat transfers, liquid crystal pictures of surface temperature, and viscous layer surveys....
Topics: DTIC Archive, Kubota,H, COLLEGE OF AERONAUTICS CRANFIELD (ENGLAND), *SHOCK WAVES, *TURBULENT...
NASA Technical Documents
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A workshop proceedings concerned with the new data collected during the 1982-1984 eclipse period of the 27-year system Epsilon Aurigae is presented. This binary star has been a classic problem in astrophysics because the opaque eclipsing object is nonstellar, and probably disk shaped. Invited papers concerning the history of the system, optical, infrared and ultraviolet photometry, optical polarimetry and ultraviolet spectroscopy are included. An invited paper concerning comprehensive...
Topics: HELICOPTERS, PREDICTIONS, RATIOS, LASER ANEMOMETERS, ROTARY WINGS, TIP SPEED, VELOCITY MEASUREMENT,...
Defense Technical Information Archive
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The state of Hawaii identified the need for Barbers Point Harbor to accommodate larger ships and increase the number of available berths. Modifications to the harbor were proposed, including widening the entrance channel, and deepening (from 38 to 45 ft) and expanding the harbor basin (1,000-ft by 1,100-ft area on the northeast side of the harbor). Physical and numerical (computer) model studies were conducted from September 1990 to June 1992 at the U.S. Army Engineer Waterways Experiment...
Topics: DTIC Archive, Briggs, Michael J., COASTAL ENGINEERING RESEARCH CENTER VICKSBURG MS, *OCEAN WAVES,...
The purpose of the reconnaissance phase study is to review water resource problems and opportunities in the WLHB study area, consistent with the study authority, and to determine if there is a Federal (Corps) interest in participating in a cost-shared, feasibility phase study (or studies) to investigate and recommend plans and projects that warrant Federal participation. Federal interest means that a proposed project or remedy to a watershed problem or impairment falls within a Corps mission...
Topics: DTIC Archive, CORPS OF ENGINEERS DETROIT MI DETROIT DISTRICT, *LAKE HURON, *WATER RESOURCES,...
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A detailed experimental investigation to understand and quantify the development of loss and blockage in the flow field of a transonic, axial flow compressor rotor has been undertaken. Detailed laser anemometer measurements were acquired upstream, within, and downstream of a transonic, axial compressor rotor operating at design and off-design conditions. The rotor was operated at 100%, 85%, 80%, and 60% of design speed which provided inlet relative Mach numbers at the blade tip of 1.48, 1.26,...
Topics: NASA Technical Reports Server (NTRS), FLOW DISTRIBUTION, TRANSONIC FLOW, TURBOCOMPRESSORS, MACH...
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A ship computer simulation study for Houston-Galveston Navigation Channels, TX, is performed. The study includes existing conditions and two proposed channel widths. The primary design question is related to ships meeting and passing in the narrow channels. Recommendations are made concerning channel width. Houston-Galveston Navigation Channels, Ship navigation simulation, Ships meeting and passing.
Topics: DTIC Archive, Hewlett, J C, ARMY ENGINEER WATERWAYS EXPERIMENT STATION VICKSBURG MS, *SHIPS, *SHIP...
The Houston/Galveston Navigation Channels are located along the Gulf of Mexico Coast in eastern Texas. These channels include the Entrance Channel, the Bar Channels (Bolivar Roads Area), Galveston Channel, the Texas City Channel, the Gulf Intercoastal Waterway (GIWW), and the Houston Ship Channel (HSC), which branches off the Bolivar Roads Channel, traverses Galveston Bay, and ends in Houston. The HSC consists of approximately 65 miles of improved deep-draft channels. The present channel is 400...
Topics: DTIC Archive, Webb, Dennis W, ARMY ENGINEER WATERWAYS EXPERIMENT STATION VICKSBURG MS HYDRAULICS...
Defense Technical Information Archive
by Defense Technical Information Center
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A real-time ship simulation investigation of the proposed designs for deepening and narrowing the navigation channel for Grand Haven Harbor, Michigan, was conducted. The purpose of the study was to determine if the navigation channel could be deepened from 21 to 27 ft and narrowed from the existing 300 ft to 225 ft and maintain adequate safety. A numerical model of the existing channel from Lake Michigan to the supper limit of the maintained channel was developed. The numerically generated...
Topics: DTIC Archive, McCollum, Randy A, ARMY ENGINEER WATERWAYS EXPERIMENT STATION VICKSBURG MS HYDRAULICS...
Defense Technical Information Archive
by Defense Technical Information Center
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Two wave gages were operated at Lidington Harbor, Michigan, from May 1983 to December 1983. The objective of the study was to determine the relationship of wave action in the harbor with wave action occurring in Lake Michigan. One gage was located in Lake Michigan just outside the harbor; the other was located in the interior channel near ferry terminal number 1. Concurrent wind data were obtained at the Ludington Harbor Coast Guard Station. Interpretation of the results and conclusions are...
Topics: DTIC Archive, Horsham,G M, COASTAL ENGINEERING RESEARCH CENTER VICKSBURG MS, *WATER WAVES,...
Biodiversity Heritage Library
by Sheng, Y. Peter; United States. Army. Corps of Engineers; Aeronautical Research Associates of Princeton; Hydraulics Laboratory (U.S.); Coastal Engineering Research Center (U.S.); U.S. Army Engineer Waterways Experiment Station
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Final report
Topics: Hydrodynamics, Ocean currents, Sediment transport
Biodiversity Heritage Library
by Marks, Wilbur; United States. Beach Erosion Board; New York University. School of Engineering and Science
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"Preliminary distribution ; Prepared under a contract sponsored by the Beach Erosion Board, Corps of Engineers, Dept. of the Army."
Topics: Refraction, Diffraction, Water waves, Sound-waves, Light
Biodiversity Heritage Library
by Warner, K. K; U.S. Navy Electronics Laboratory (San Diego, Calif.)
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Bibliography: p. 50
Topic: Sound-waves
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The application of the laser velocimeter in the study of two highly complex aerodynamic flows is discussed. In the first experiment, the laser velocimeter was used with frequency tracking electronics to survey the multiple vortex wake structure behind a model of a large jet transport. The second application is to the study of the induced instantaneous inflow velocities near the blades of a model helicopter rotor; counter-type processing was used in these measurements. In each experiment, the...
Topics: NASA Technical Reports Server (NTRS), AERODYNAMICS, FLOW MEASUREMENT, LASER DOPPLER VELOCIMETERS,...
Tests were conducted to demonstrate a rapid scan two dimensional laser velocimeter (LV) measurement technique for aerial applications research. The LV system is capable of simultaneously measuring both vertical and axial flow velocity components in a near or far field vortex system. Velocity profiles were successfully measured in the wake vortex of a representative agricultural aircraft model, with the vortex system rapidly transporting in ground effect. Results indicate that the laser...
Topics: NASA Technical Reports Server (NTRS), LASER APPLICATIONS, SCANNERS, VELOCITY MEASUREMENT, VORTICES,...
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A low-speed multistage axial compressor built by the NASA Lewis Research Center is described. The purpose of this compressor is to increase the understanding of the complex flow phenomena within multistage axial compressors and to obtain detailed data from a multistage compressor environment for use in developing and verifying models for computational fluid dynamic code assessment. The compressor has extensive pressure instrumentation in both stationary and rotating frames of reference, and has...
Topics: NASA Technical Reports Server (NTRS), CASES (CONTAINERS), COMPRESSOR BLADES, HUBS, INTERNAL FLOW,...
A baseline compressor test stage was designed as well as a candidate rotor and two candidate stators that have the potential of reducing endwall losses relative to the baseline stage. These test stages are typical of those required in the rear stages of advanced, highly-loaded core compressors. The baseline Stage A is a low-speed model of Stage 7 of the 10 stage AMAC compressor. Candidate Rotor B uses a type of meanline in the tip region that unloads the leading edge and loads the trailing edge...
Topics: NASA Technical Reports Server (NTRS), AERODYNAMIC CHARACTERISTICS, COMPRESSOR BLADES, COMPRESSOR...
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The National Advisory Committee for Aeronautics (NACA) was founded in 1915 and remained at the forefront of aeronautic research and exploration until the launch of Sputnik triggered the American imagination with regards to space. NACA became NASA on October 1, 1958. This collection of NACA documentation was donated to the University of Florida Government Document Department by former UF Provost, Gene Hemp.
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Arxiv.org
by Andrew R Casey
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There exists an inordinate amount of spectral data in both public and private astronomical archives which remain severely under-utilised. The lack of reliable open-source tools for analysing large volumes of spectra contributes to this situation, which is poised to worsen as large surveys successively release orders of magnitude more spectra. In this Article I introduce sick, the spectroscopic inference crank, a flexible and fast Bayesian tool for inferring astrophysical parameters from...
Topics: Astrophysics, Solar and Stellar Astrophysics, Instrumentation and Methods for Astrophysics
Source: http://arxiv.org/abs/1603.03043
Arxiv.org
by Roberta M. Humphreys
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The luminosity of the famous red supergiant VY CMa (L ~ 4 - 5 x 10e5 Lsun) is well-determined from its spectral energy distribution and distance, and places it near the empirical upper luminosity limit for cool hypergiants. In contrast, its surface temperature is fundamentally ill-defined. Both contradict a recent paper by Massey, Levesque and Plez (2006). Implications for its location on the HR Diagram and its apparent size are discussed.
Source: http://arxiv.org/abs/astro-ph/0610433v1
This paper implements and analyzes a dual-primal iterative substructuring method for the parallel and scalable solution of a three-dimensional finite element based dynamic analysis of helicopter rotor blades. Scalability and solution times are studied using two prototype problems -- one for steady hover (symmetric) and one for transient forward flight (non-symmetric) -- carried out on up to 128 processors. Several problem sizes of up to 0.48 million degrees of freedom are considered. A linear...
Topics: DTIC Archive, ELORET CORP MOFFETT FIELD CA NASA AMES RESEARCH CENTER, *DECOMPOSITION, *FINITE...
Naval Postgraduate School
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Motivation to expand the understanding of a helicopter rotor descending into the vortex ring state (VRS) stems from the aircraft mishaps that have plagued the helicopter community. The V-22 has become the most recent victim of encounters with VRS. The onset of VRS is associated with the collapse of the helical vortex wake in the plane of the rotor. The resulting wake disturbances develop an irregular and aperiodic flow. Rotor blade interaction with the disturbed vortices causes large variations...
Topics: Vortex-motion, Vibration (Aeronautics)
Department of Defense
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Thesis advisor(s): Garth V. Hobson
Dissertation advisor(s): Shreeve, R.P
Topic: Aeronautics,Cascades (Fluid dynamics),Laser Doppler velocimeter,Fluid dynamics,Stalling...
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Resonant excitation tests of rotor blades in vacuum spin pits using discrete oil jets showed that impact erosion of the blades could limit test times, but lower excitation amplitudes were produced using mist nozzles. Smaller diameter discrete jets might extend test times, but to fully prevent erosion, oil mist droplet size needed to be 30 microns or less. The present study examined both approaches. Prototype nozzles were developed to create 0.005 inch diameter multiple discrete jets using first...
Topics: Laser Doppler velocimeter, Nozzles, Fluid dynamics, Mechanical engineering, Testing laboratories,...
Naval Postgraduate School
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Flapping-wing propulsion is studied experimentally and numerically. The objective of the research is to provide further insight into the aerodynamics of flapping-wing air vehicles. Experimental work is conducted in the NPS 1.5 m x 1.5 m (5 ft x 5 ft) in-draft wind tunnel. A previously constructed long-span flapping-wing model suspended by cables is used to approximate the two-dimensional nature of the numerical simulation. For this experiment, the model is configured with two wings executing...
Topics: Flapping-wing, Low Reynolds number, USPOT, Panel code, Laser Doppler velocimetry, LDV
An investigation of vortex shedding downstream of a cascade of second-generation, controlled-diffusion, compressor stator blades, at off-design inlet-flow angles of 31, 33 and 35 degrees and Reynolds numbers, based on chord length, of 280,000, 380,000 and 640,000 is reported. The objective of the study was to characterize the flow and shedding through various complementary methods. Blade surface pressure measurements were taken from a fully instrumented blade, and distributions of pressure...
Topics: Aerospace engineering, Vortex-motion, Controlled-diffusion, Compressor, Stator, Cascade,...
An investigation of vortex shedding downstream of a cascade of compressor stator blades, at off-design inlet-flow angles of 35, 33 and 31 degrees and Reynolds numbers, based on chord length, of 625,000, 750,000 and 800,000 is reported. The objective of the study was to characterize the flow and vortex shedding through blade surface pressure measurements and hot-wire anemometry. Vortex shedding was determined to be a leading edge phenomenon as periodic shedding was only detected on the pressure...
Topics: Vortex-motion, Reynolds number
Arxiv.org
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We study the singular limit of a rotating compressible fluid described by a scaled barotropic Navier-Stokes system, where the Rossby number, the Mach number and the Froude number tend to 0 in a particular mutual rate while the Reynolds number tends to infinity. The inviscid planar Euler system is identified as the limit problem. The proof is based on the application of the method of relative entropies and careful analysis of oscillatory integrals describing the propagation of Rossby-acoustic...
Source: http://arxiv.org/abs/1303.3998v1