The development of a turbulent boundary layer flow through a gap in an isolated wall-mounted roughness element has been studied experimentally. Two flow regions were distinguished downstream of the gap; a distortion region followed by a readjustment region. In the distortion region two counteracting distortion mechanisms were identified, the relative importance of which depended on gap size. Thus flows downstream of large gaps were found to differ significantly from those through small gaps....
Topics: DTIC Archive, Schofield,W H, AERONAUTICAL RESEARCH LABS MELBOURNE (AUSTRALIA), *SURFACE ROUGHNESS,...
This grant developed a low-noise, two-velocity-component flow measurement system was developed. It consists of a two-color Laser-Doppler anemometer and a two-channel hot-wire system.
Topics: DTIC Archive, Saric, William S, ARIZONA STATE UNIV TEMPE DEPT OF MECHANICAL AND AEROSPACE...
This report gives details of how to use the constant-temperature hot-wire-anemometer system at DST Group to measure mean velocities, broadband turbulence terms and spectra of velocity fluctuations in the low-speed wind tunnel at DST Group. The use of both single-wire and crossed-wire (2 wire) probes is described. Areas covered include a description of the anemometers and probes, soldering hot-wire filaments onto the prongs of a probe, etching the filaments, setting up of instrumentation,...
Topics: DTIC Archive, Erm,Lincoln P, DEFENCE SCIENCE AND TECHNOLOGY ORGANISATION FISHERMANS BEND...
Understanding the nature of premixed combustion in highly turbulent conditions and in compressible flow offers a new paradigm shift in the design of future high-pressure gas turbines and scramjets. Experimental data in these regimes provides hitherto unavailable insight and offer new ways to develop accurate and efficient computational models of turbulent premixed combustion, especially subgrid-scale (SGS) models for large-eddy simulation (LES). In these studies, comprehensive experimental...
Topics: DTIC Archive, Menon,Suresh, Georgia Institute of Technology Atlanta United States, combustion,...
This project conducted complementary experimental and numerical studies of flow-acoustic resonant interactions in transitional airfoils and their impact on airfoil surface unsteady pressure and acoustic signature. The symmetric NACA-0012 airfoil and the slightly cambered SD7003 airfoil at moderate incidence were tested in the free-jet anechoic wind tunnel of Ecole Centrale de Lyon. Measurements of wall pressure, far -field acoustic pressure and velocity fluctuations using the hot-wire...
Topics: DTIC Archive, EMBRY-RIDDLE AERONAUTICAL UNIV DAYTONA BEACH FL, *ACOUSTIC SIGNATURES, *AERODYNAMICS,...
The invention proposed herein is a system and method for measuring the liquid level in a container that employs an optic fiber sensor which is heated using a simple power source and a wire and making an anemometry measurement. The heater wire is cycled between two levels of heat and the liquid level is obtained by measuring the heat transfer characteristics of the surrounding environment.
Topics: NASA Technical Reports Server (NTRS), CRYOGENICS, LIQUID LEVELS, MEASURING INSTRUMENTS, OPTICAL...
The work presented within compares the wind readings obtained from a weapon mountable hot wire anemometer and co-located down range laser wind sensor to the data collected from a string of propeller and vane anemometers set up along a firing line. The purpose of this effort was to determine if a combination of the two sensors would be able to measure the wind conditions a projectile would be subject to along its flight path to a target. The results of the work showed that the sensor suite was...
Topics: DTIC Archive, Bober,Tomas R, ARDEC Picatinny Arsenal United States, fire control systems, hot wire...
Hotwire anemometers are used to measure instantaneous velocity from which the mean velocity and the velocity fluctuation can be determined. Using a hotwire system, it is possible to deduce not only the velocity components and their fluctuation but to also analyze the energy spectra and from that the turbulence length scales. In this experiment, hotwire anemometry is used to measure the flow field turbulence for an array of film cooling holes. The objective of this paper is to document the...
Topics: NASA Technical Reports Server (NTRS), PROCEDURES, HOT-WIRE ANEMOMETERS, VELOCITY MEASUREMENT,...
An experiment investigating flow and heat transfer of long (length to diameter ratio of 18) cylindrical film cooling holes has been completed. In this paper, the thermal field in the flow and on the surface of the film cooled flat plate is presented for nominal freestream turbulence intensities of 1.5 and 8 percent. The holes are inclined at 30deg above the downstream direction, injecting chilled air of density ratio 1.0 onto the surface of a flat plate. The diameter of the hole is 0.75 in....
Topics: NASA Technical Reports Server (NTRS), STRUCTURAL ANALYSIS, REYNOLDS NUMBER, HOLE GEOMETRY...
Unsteady active flow control (AFC) has been used experimentally for many years to minimize bluff-body drag. This technology could significantly improve performance of rotorcraft by cleaning up flow separation. It is important, then, that new actuator technologies be studied for application to future vehicles. A boundary layer wind tunnel was constructed with a 1ft-x-3ft test section and unsteady measurement instrumentation to study how AFC manipulates the boundary layer to overcome adverse...
Topics: NASA Technical Reports Server (NTRS), HOT-FILM ANEMOMETERS, HOT-WIRE ANEMOMETERS, BOUNDARY LAYER...
A major modification of the refrigeration plant and heat exchanger at the NASA Glenn Icing Research Tunnel (IRT) occurred in autumn of 2011. It is standard practice at NASA Glenn to perform a full aero-thermal calibration of the test section of a wind tunnel facility upon completion of major modifications. This paper will discuss the tools and techniques used to complete an aero-thermal calibration of the IRT and the results that were acquired. The goal of this test entry was to complete a flow...
Topics: NASA Technical Reports Server (NTRS), AERODYNAMIC HEATING, ICE FORMATION, WIND TUNNEL CALIBRATION,...
The NPS MAE wind tunnel was reinstalled, calibrated, and its flow characteristics evaluated to determine its suitability for research and classroom demonstration. The calibration involved determining tunnel speed vs. motor speed, wall static pressure distribution, total pressures across selected planes, the uniformity of the velocity profile, using a pitot-static tube and a single component hot wire (CTA), the wall boundary layer characteristics consisting of the velocity profile, streamwise...
Topics: DTIC Archive, NAVAL POSTGRADUATE SCHOOL MONTEREY CA, *TEST AND EVALUATION, *WIND TUNNELS,...
An experiment is conducted on the effectiveness of a vortex generator in preventing liftoff of a jet in crossflow, with possible relevance to film-cooling applications. The jet issues into the boundary layer at an angle of 20 degreees to the freestream. The effect of a triangular ramp-shaped vortex generator is studied while varying its geometry and location. Detailed flowfield properties are obtained for a case in which the height of the vortex generator and the diameter of the orifice are...
Topics: NASA Technical Reports Server (NTRS), CROSS FLOW, VORTEX GENERATORS, JET FLOW, FILM COOLING,...
Film cooling flows subject to periodic wakes were studied experimentally. The wakes were generated with a spoked wheel upstream of a flat plate. Cases with a single row of cylindrical film cooling holes inclined at 35 deg to the surface were considered at blowing ratios of 0.25, 0.50, and 1.0 with a steady freestream and with wake Strouhal numbers of 0.15, 0.30, and 0.60. Temperature measurements were made using an infrared camera, thermocouples, and constant current (cold-wire) anemometry....
Topics: DTIC Archive, NAVAL ACADEMY ANNAPOLIS MD DEPT OF MECHANICAL ENGINEERING, *FLOW, *TURBOMACHINERY,...
This report describes the velocity profile characterization of the 5-cm Agent Fate Wind Tunnel. This facility, which fits in a standard chemical fume hood, is used to measure the release and retention of chemical warfare agents from various materials under simulated environmental conditions. The tunnel creates specified vertical velocity profiles representing the lower portion of the velocity profile produced by a wind-induced, atmospheric boundary layer. Characterization refers to the...
Topics: DTIC Archive, Weber, Daniel J, EDGEWOOD CHEMICAL BIOLOGICAL CENTER ABERDEEN PROVING GROUND MD,...
Temporally Resolved Particle Image Velocimetry (TR-PIV) is being used to characterize the decay of turbulence in jet flows a critical element for understanding the acoustic properties of the flow. A TR-PIV system, developed in-house at the NASA Glenn Research Center, is capable of acquiring planar PIV image frame pairs at up to 10 kHz. The data reported here were collected at Mach numbers of 0.5 and 0.9 and at temperature ratios of 0.89 and 1.76. The field of view of the TR-PIV system covered 6...
Topics: NASA Technical Reports Server (NTRS), CORRELATION, PARTICLE IMAGE VELOCIMETRY, SPACE-TIME...
In an effort to explore efficient wing designs for UAV's, the Air Force is investigating the patented Houck Aircraft Configuration, which is a joined-wing aircraft with curved flow guides of varying camber connecting the upper and lower wingtips. Models were drawn in three-dimensions using Solidworks(registered) with upper and lower wings drawn as identical NACA 2412 airfoil sections for all models. A variety of airfoil sections between the upper and lower wingtips were drawn and rotated to...
Topics: DTIC Archive, Killian, Dermot N, AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH DEPT OF AERONAUTICS...
Characteristics and aerosol sampling efficiencies of a Portable High Throughput Liquid-Assisted Air Sampler Model APAS-2 (PHTLAAS-APAS-2) (Zaromb Research Corp., Hinsdale, IL) were determined at the U.S. Army Edgewood Chemical Biological Center (ECBC). The PHTLAAS-APAS-2 is a portable, battery-operated bioaerosol sampler designed to collect 0.5- to 10-micrometers particles into a buffer solution to preserve the viability of bio-organisms. Sampling efficiency tests were conducted with 1- and...
Topics: DTIC Archive, Kesavan, Jana S, MITRETEK SYSTEMS FALLS CHURCH VA, *AEROSOLS, *SAMPLERS, PORTABLE...
A detailed investigation of the flow physics occurring on the suction side of a simulated Low Pressure Turbine (LPT) blade was performed. A contoured upper wall was designed to simulate the pressure distribution of an actual LPT airfoil onto a flat lower plate. The experiments were carried out for the Reynolds numbers of 35,000, 70,000, 100,000, and 250,000 with four levels of freestream turbulence ranging from 1 to 4 percent. For the three lower Reynolds numbers, the boundary layer on the flat...
Topics: NASA Technical Reports Server (NTRS), LOW PRESSURE, TRANSITION FLOW, TURBINE BLADES, COMPUTERIZED...
This research was done as part of an effort to develop alternative fire suppressant technologies for aircraft engine nacelles. A circular cylinder array was designed, built, and placed in the AFIT roll-around low speed wind tunnel to model generic clutter inside an engine nacelle. A turbulence grid was fabricated to enable measurements of the effects of turbulence level, independent of airspeed, on the flow over different model configurations. The wind tunnel test section was 12 inches wide x...
Topics: DTIC Archive, Harder, Adam D, AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH GRADUATE SCHOOL OF...
Detailed measurements of velocity statistics, temperature distribution, flame chemiluminescence, and emission characteristics in a lean direct fuel injection multi swirl gas turbine combustor were acquired. The inlet and exit boundary conditions, including the mixing tube length and the exhaust nozzle contraction ratio, were modified to emphasize the effects of these boundary conditions on the characteristics of nonreacting and reacting flows. Velocity statistics, including mean and turbulence...
Topics: DTIC Archive, Gutmark, Ephraim, CINCINNATI UNIV OH GRADUATE STUDIES AND RESEARCH, *VELOCITY,...
This report describes development of a 5-cm wind tunnel designed to measure the release and retention of chemical warfare agents (CWA) from various materials under simulated environmental conditions. The wind tunnel, sized to fit within a standard chemical fume hood, provides a specified vertical velocity profile, temperature, and relative humidity (simulating the natural environment) for a sustained time period ranging from hours to weeks. The associated data acquisition instrumentation...
Topics: DTIC Archive, Weber, Daniel J, EDGEWOOD CHEMICAL BIOLOGICAL CENTER ABERDEEN PROVING GROUND MD...
The purpose of this research was to improve the MAV that will be used for battle damage assessment and reconnaissance or local surveillance through the experiments in AFIT wind tunnel. The experiments were performed to investigate the wing displacement and wing tip vortex interaction. To conduct the experiments, telescopic survey tool and tri-axial hot-wire anemometer was utilized. The results indicate that wing tip displacement of the flexible wing was approximately 8 times that of the rigid...
Topics: DTIC Archive, Park, Hong J, AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING...
The Naval Postgraduate School (NPS) Micro-Air Vehicle (MAV) wind tunnel was refurbished in this study. This wind tunnel has a 61 by 38 centimeter test section with a contraction ratio of 6.75, and testing speeds up to 9 meters per second (m/s). The objectives of this work were to create a high quality, customized facility for further MAV study, and to fully characterize the wake of the MAV at a plane downstream of the model. Extensive repairs were made to the wind tunnel intake, test section,...
Topics: DTIC Archive, Hickle, Curtis, NAVAL POSTGRADUATE SCHOOL MONTEREY CA, *FLOW VISUALIZATION,...
The work to be presented herein was motivated largely by a desire to improve the understanding of oscillatory fluid mechanics inside a Stirling engine. To this end, a CFD project was undertaken at Cleveland State University with the goal of accurately predicting the fluid dynamics within an engine or engine component. Along with the CFD efforts, a code validation project was undertaken at the University of Minnesota. The material covered herein consists of four main parts. In section 1, an...
Topics: NASA Technical Reports Server (NTRS), COMPUTATIONAL FLUID DYNAMICS, ENGINE DESIGN, FLOW...
A Point Doppler Velocimeter (pDv) has been developed using a vapor-limited iodine cell as the sensing medium. The iodine cell is utilized to directly measure the Doppler shift frequency of laser light scattered from submicron particles suspended within a fluid flow. The measured Doppler shift can then be used to compute the velocity of the particles, and hence the fluid. Since this approach does not require resolution of scattered light from individual particles, the potential exists to obtain...
Topics: NASA Technical Reports Server (NTRS), FLUID FLOW, FLOW DISTRIBUTION, VELOCITY MEASUREMENT, LASER...
An investigation into the effects of the propeller slipstream on a flexible wing micro-air-vehicle (MAV) was conducted. The Air Force Research Lab, Munitions Directorate designed a man-portable MAV with a 24 in. wingspan and 6 in. root chord to be used for battle damage assessment and reconnaissance. Two wings have been developed for this MAV. One is a rigid carbon-fiber wing and the other consists of flexible parachute material attached to a carbon-fiber skeleton. Experimental methods were...
Topics: DTIC Archive, Gamble, Brian J, AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING...
As future aircraft migrate toward tailless, blended wing body configurations, aircraft designers are faced with a lack of experimental data that represent these types of configurations. A wind tunnel investigation was conducted to identify the ground effect region of two unmanned combat air vehicle (UCAV) models. The AFIT low-speed wind tunnel (LSWT) and ground plane were used to study the forces and moments on the UCAV models in ground effect. The Chevron and Lambda planforms used in this...
Topics: DTIC Archive, In, Won, AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH DEPT OF AERONAUTICS AND...
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Xu, Tian-Bing; Su, Ji; Jiang, Xiaoning; Rehrig, Paul W.; Zhang, Shujun; Shrout, Thomas R.; Zhang, Qimin
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An electroactive polymer (EAP)-ceramic hybrid actuation system (HYBAS) was developed recently at NASA Langley Research Center. This paper focuses on the effect of the bending stiffness of the EAP component on the performance of a HYBAS, in which the actuation of the EAP element can match the theoretical prediction at various length/thickness ratios for a constant elastic modulus of the EAP component. The effects on the bending stiffness of the elastic modulus and length/thickness ratio of the...
Topics: FLUID FLOW, PARTICLE IMAGE VELOCIMETRY, FREQUENCY RESPONSE, FLOW DISTRIBUTION, VELOCITY...
Steam leakage from an aircraft carrier catapult is sometimes ingested by the aircraft's engines upon launch which may induce compressor stall. Investigation of the phenomenon known as a pop stall is of particular importance as the Navy prepares to field the F35C, the aircraft carrier variant of the joint strike fighter. The single engine design of the F-35C makes this aircraft particularly susceptible to steam-induced stall during catapult launch. The present project examined compressor stall...
Topics: DTIC Archive, Payne, Thomas A, NAVAL POSTGRADUATE SCHOOL MONTEREY CA, *STALLING, *TRANSONIC FLOW,...
Surface evaporation and desorption sub-models in VLSTRACK require measurements of chemical warfare agent evaporation and desorption under environmental conditions. A 5cm square by approximately I meter wind tunnel for chemical agent measurements was developed with optional strakes and roughening elements to add turbulence. Flow was developed in the pull-mode by an electric blower system. Several candidate intake geometries were designed that allowed controlled restriction of air intake to...
Topics: DTIC Archive, Weber, Daniel J, EDGEWOOD CHEMICAL BIOLOGICAL CENTER ABERDEEN PROVING GROUND MD,...
An important goal is to model chemical warfare agent fate on environmental and interior surfaces and therefore, rigorously measured evaporation and desorption rates are required to develop equations for these transport processes. A difficult problem in environmental fate research is the assignment of a wind speed to an evaporation or desorption process for a droplet. The average wind speed is recorded, but the wind speed controlling the transport of liquid to vapor at the droplet interface at...
Topics: DTIC Archive, Weber, Daniel J, EDGEWOOD CHEMICAL BIOLOGICAL CENTER ABERDEEN PROVING GROUND MD,...
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Hultgren, Lennart; Ashpis, David E
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Modern low-pressure turbines, in general, utilize highly loaded airfoils in an effort to improve efficiency and to lower the number of airfoils needed. Typically, the airfoil boundary layers are turbulent and fully attached at takeoff conditions, whereas a substantial fraction of the boundary layers on the airfoils may be transitional at cruise conditions due to the change of density with altitude. The strong adverse pressure gradients on the suction side of these airfoils can lead to...
Topics: BOUNDARY LAYER STABILITY, SURFACE TEMPERATURE, TEMPERATURE MEASUREMENT, TRANSITION FLOW, HYPERSONIC...
A ducted fan VTOL UAV with a 10-inch diameter rotor was tested in the US Amy 7-by-10-Foot Wind Tunnel. The test conditions covered a range of angle of attack from 0 to 110 degrees to the freestream. The tunnel velocity was varied from 0 (simulating a hover condition) to 128 ft/sec in propeller mode. A six-component internal balance measured the aerodynamic loads for a range of model configurations, including the isolated rotor, the isolated duct, and the full configuration of the duct and...
Topics: DTIC Archive, ARMY RESEARCH DEVELOPMENT AND ENGINEERING COMMAND MOFFETT FIELD CA AVIATION...
An experimental study was conducted in a simulated three vane linear cascade to determine the effects of surface roughness and film cooling on the heat transfer coefficient distribution in the region downstream of the first row of suction side coolant holes. Suction side film cooling was operated in the range 0 less than M less than 1.4. The showerhead was tested at M(sub sh) = 1.6. In addition to the completely smooth condition, simulated airfoil roughness was used upstream of the coolant...
Topics: DTIC Archive, Rutledge, James L, TEXAS UNIV AT AUSTIN, *HEAT TRANSFER, *GAS TURBINES, *TURBINES,...
Wind tunnel studies on the laminar-to-turbulent transition mechanism known as transient growth require instrumentation suitable for the production of high but controllable levels of freestream turbulence, model surfaces relevant to transition problems of engineering interest, and hotwire instrumentation suitable for measuring disturbances that lead to transition. Ongoing and planned experiments on transient growth at the Case Western Reserve University Wind Tunnel Laboratory required...
Topics: DTIC Archive, White, Edward B, CASE WESTERN RESERVE UNIV CLEVELAND OHDEPT OF MECHANICAL AND...
An oscillatory zero net mass flow jet was generated by a cavity-pumping device, namely a synthetic jet actuator. This basic oscillating jet flow field was selected as the first of the three test cases for the Langley workshop on CFD Validation of Synthetic Jets and Turbulent Separation Control. The purpose of this workshop was to assess the current CFD capabilities to predict unsteady flow fields of synthetic jets and separation control. This paper describes the characteristics and flow field...
Topics: NASA Technical Reports Server (NTRS), JET FLOW, DATA BASES, COMPUTATIONAL FLUID DYNAMICS, FLOW...
Freestream and boundary layer measurements are made in a supersonic flow using both constant temperature (CTA) and constant voltage (CVA) anemometry. The performance of both anemometers is systematically made by operating the same hot-wire under identical conditions and applying post-test software corrections to the fluctuating measurements. In the case of the CVA the in situ time constant of the hot wire is measured to compensate the measured CVA output. The measurements show that when the...
Topics: DTIC Archive, Chokani, Ndaona, NORTH CAROLINA STATE UNIV AT RALEIGH OFFICE OF CONTRACTS AND GRANTS,...
An understanding of the fate and effects of chemical agents on material surfaces under environmental conditions is becoming critical as the probability of contamination increases for military and civilian airports and seaports and Homeland targets. The methodology is not available for measuring the fundamental evaporation, desorption, and decomposition of chemical agents as a function of time in a controlled laboratory wind tunnel. The methodologies under development can be classified by the...
Topics: DTIC Archive, Weber, Daniel, EDGEWOOD CHEMICAL BIOLOGICAL CENTER ABERDEEN PROVING GROUND MD, *WIND...
Circulation control wings are a type of pneumatic high-lift device that have been extensively researched as to their aerodynamic benefits. However, there has been little research into the possible airframe noise reduction benefits of a circulation control wing. The key element of noise is the jet noise associated with the jet sheet emitted from the blowing slot. High aspect-ratio jet acoustic results (aspect-ratios from 100 to 3,000) from a related study showed that the jet noise of this type...
Topics: NASA Technical Reports Server (NTRS), HIGH ASPECT RATIO, FLOW CHARACTERISTICS, JET AIRCRAFT NOISE,...
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: DTIC Archive, Lim, Choon P, NAVAL POSTGRADUATE SCHOOL MONTEREY CA, *VORTEX SHEDDING, *REYNOLDS...
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Haberle, R. M.; Montmessin, F.; Forget, F.; Spiga, A.; Colaprete, A
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Mars has a natural mechanism for experiencing significant climate change and redistributing surface ice. Obliquity changes alone are quite capable of moving ice into low latitudes and may provide an explanation for the many geological landforms that strongly indicate recent climate change.
Topics: JET FLOW, DATA BASES, COMPUTATIONAL FLUID DYNAMICS, FLOW DISTRIBUTION, UNSTEADY FLOW, SEPARATED...
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: DTIC Archive, Brown, Peter J, NAVAL POSTGRADUATE SCHOOL MONTEREY CA, *VORTEX SHEDDING, *LASERS,...
Wind noise is recognized as one the primary environmental factors that limits the performance of battlefield acoustic sensors. Microphone windscreens are regularly used to reduce wind noise and the characterization of their performance is an important component of the acoustic sensor design, Textron Systems has extensive experience studying the performance of windscreens and have developed test methodology that allows for repeatable measurements in a controlled environment. Wind noise...
Topics: DTIC Archive, Maniet, Edward R , Jr, TEXTRON SYSTEMS CORP WILMINGTON MA, *WIND TUNNELS, *ACOUSTIC...
A need has arisen for the development of RANS models for the prediction of scalar fluctuations and turbulent transport in the high speed flow regime. These models will have application, for example, in scramjet combustors and missile exhaust plume signature analyses and other important areas. However, in the high speed flow regime, experimentally derived scalar fluctuation validation data is not readily available due to the inability of relevant experimental measurement techniques (e.g. hot...
Topics: DTIC Archive, Calhoon, William H., Jr., Kannepalli, Chandrasekhar, Dash, Sanford M., CRAFT...
Flow diagnostic instrumentation to measure turbulent flow in research and instructional wind tunnels was acquired. These instruments include a multi-channel hot-wire anemometer and a recently developed optical analysis system based on a two-dimensional Hartmann sensor. Four CTA channels for velocity and two CCA channel for temperature are included. The optical analysis system includes a PC for acquisition of phase and intensity optical measurements in a two-dimensional array. These systems...
Topics: DTIC Archive, Truman, C R, NEW MEXICO UNIV ALBUQUERQUE DEPT OF MECHANICAL ENGINEERING, *TURBULENT...
Flow diagnostic instrumentation to measure turbulent flow in research and instructional wind tunnels was acquired. These instruments include a multi-channel hot-wire anemometer and a recently developed optical analysis system based on a two-dimensional Hartmann sensor. Four CTA channels for velocity and two CCA channel for temperature are included. The optical analysis system includes a PC for acquisition of phase and intensity optical measurements in a two-dimensional array. These systems...
Topics: DTIC Archive, Truman, C R, NEW MEXICO UNIV ALBUQUERQUE DEPT OF MECHANICAL ENGINEERING, *TURBULENT...
Vortex-driven instability in a solid rocket motor and its active control via secondary injection were studied in a cold-flow experimental model. All tests were conducted in an 86-cm-long, 5- cm-square airflow chamber. Twin orifice plates at the center of the chamber produced a 21 5-Hz vortex-driven pressure instability with 2% peak-to-peak oscillations near the first longitudinal chamber mode. Hot-wire anemometer data at the vortex shedding frequency indicate that the organized structures occur...
Topics: DTIC Archive, Petersen, E L, AEROSPACE CORP EL SEGUNDO CA, *OSCILLATION, *SOLID PROPELLANT ROCKET...
The objective of the study reported here was to acquire acoustic and flow data for numerical validation of impedance models that simulate bias flow through perforates. The impedance model is being developed by researchers at High Technology Corporation. This report documents normal incidence impedance measurements a singular circular orifice with mean flow passing through it. All measurements are made within a 1.12 inch (28.5 mm) diameter impedance tube. The mean flow is introduced upstream of...
Topics: NASA Technical Reports Server (NTRS), ABSORPTIVITY, ACOUSTIC ATTENUATION, IMPEDANCE MEASUREMENT,...
A two component Point Doppler Velocimetry (PDV) system has been developed and tested. Improvements were made to an earlier PDV system, in terms of experimental techniques, as well as the data acquisition and reduction software. Measurements of the streamwise and spanwise mean and fluctuating velocities for flows from a rectangular channel and over an NACA 0012 airfoil were made, and the data were compared against hot wire data. The closest to the airfoil surface that PDV measurements could be...
Topics: NASA Technical Reports Server (NTRS), VELOCITY MEASUREMENT, COMPUTATIONAL FLUID DYNAMICS, BOUNDARY...
