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Aug 1, 2020
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Aug 1, 2020
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A mathematical model is presented towards a theory of lifting and resistance on wings. It consists of a theory of multiplanes, conditions of flow at a great distance from the wing, lifting systems of minimum resistance, and free stream and stream limited by walls.
Topics: ROTOR LIFT, HIGH ALTITUDE, COMPUTATIONAL FLUID DYNAMICS, LIFT DRAG RATIO, HELICOPTERS, DRAG...
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,...
An experiment was conducted in the NASA Langley Continuous Flow Hypersonic Tunnel to measure the heat transfer and pressure distributions on finite span flaps subjected to turbulent boundary layer conditions. Data were obtained for three span widths at deflection angles below that required to induce separation at the compression corner. The results are compared with other experimental data and theoretical predictions. (Author)
Topics: DTIC Archive, Cassel,L A, SCIENCE APPLICATIONS INC IRVINE CA AERONAUTICAL SYSTEMS TECHNOLOGY DIV,...
T-117 TsAGI is a large hypersonic blowdown arc heater wind tunnel. The facility is provided with two interchangeable electrical arc heaters with a maximum power of 25 and 2.5 megawatts. The first heater is a two arcs heater and fl second one is a one arc heater. The supply air is heated between coaxial electrodes by an electric arc rotated in a magnetic field.
Topics: DTIC Archive, Boldyrev, S, TSAGI (CENTRAL AEROHYDRODYNAMIC INST) ZHUKOVSKY (RUSSIA), *HYPERSONIC...
An investigation has been conducted to determine the effect of tail length on the spin and recovery characteristics of a model typical of a trainer-type airplane. The model used in the investigation was tested with two tail lengths, and the model having the shorter tail length was tested with several ventral fins installed in order to improve its recovery characteristics. The investigation showed that the model with the longer tail length had the better recovery characteristics even when the...
Topics: DTIC Archive, Klinar, Walter J, NATIONAL AERONAUTICS AND SPACE ADMINISTRATION WASHINGTON DC,...
The PI and collaborators were interested in testing the hypothesized advantage of sensing flow disturbance before initiating an inertial response. The PI successfully completed flight trails in wind tunnels and in atmospheric turbulence. Their mitigation system reduced aircraft roll by up to 50 . In addition to the final report, the PI has 10 publications and/or conference proceedings as a result of the grant.
Topics: DTIC Archive, Watkins, Simon, ROYAL MELBOURNE INSTITUTE OF TECHNOLOGY MELBOURNE Australia,...
This interim technical report summarizes technical activity on AFRL 6.1 laboratory task LRIR 15RQCOR102 during fiscal year 2017. The objective of this task is to better understand boundary layer transition in hypersonic flowfields with spanwise nonuniformity. Several advances were made under this task during FY17. The HIFiRE-5b flight data were analyzed. Wind tunnel tests were conducted at angles of attack and yaw representative of flight, and computations were carried out for the flight...
Topics: DTIC Archive, Kimmel,Roger, Hypersonic Sciences Branch Wright-Patterson Air Force Base, flow...
This report presents the results from an ongoing effort to produce improved correlation between analytical hub force and moment prediction and those measured during wind-tunnel testing on the Aeroelastic Rotor Experimental System (ARES), a conventional rotor testbed commonly used at the Langley Transonic Dynamics Tunnel (TDT). A frequency-dependent transformation between loads at the rotor hub and outputs of the testbed balance is produced from frequency response functions measured during...
Topics: DTIC Archive, Thornburgh,Robert P, US Army Research Laboratory Aberdeen Proving Ground United...
This report presents the work and results of Wind Tunnel Model and Test to Evaluate the Effectiveness of a Passive Gust Alleviation Device for a Flying Wing Aircraft. The gust response of the aircraft by using the PGAD integrated at the wing tip was analyzed in a procedure starting from design to numerical modeling and optimization. The previous results show that the PGAD leads to gust response reduction by 18 of the elastic deflection at wingtip, and 15 of the bending moment at the wing root...
Topics: DTIC Archive, Guo,Shijun, Cranfield University Bedford United Kingdom, Wind tunnel models, test and...
Ever since computations have been used to simulate aerodynamics the need to ensure that the computations adequately represent real life has followed. Many experiments have been performed specifically for validation and as computational methods have improved, so have the validation experiments. Validation is also a moving target because computational methods improve requiring validation for the new aspect of flow physics that the computations aim to capture. Concurrently, new measurement...
Topics: 4540cd94d24c4bf29f8773a27faf96b2, Ever since computations have been used to simulate aerodynamics...
Based on our preceding studies on the aerodynamics of a falcoperegrinus in diving flight along avertical dam it is known that even when the body shape of the bird is rather streamlined in V-shape some feathers tips may elevate in certain regions of the body. These regions were identified in wind tunnel tests for typical diving flight conditions as regions of locally separated flow. A life-size model in V-shape of a falcoperegrinus with artificial feathers fixed along the body was studied in a...
Topics: DTIC Archive, Bruecker,Christoph, City University London London United Kingdom, BIRDS, flight,...
The Aviation Development Directorate of the U.S. Army Aviation and Missile Research, Development and Engineering Center (AMRDEC) conducted a drag test of a non-rotating 2/5 scale Lockheed AH-56 Cheyenne main rotor hub in the U.S. Army 7 by 10foot Wind Tunnel located at NASA Ames Research Center in Moffett Field, CA. The purpose of the test was to quantify the drag reduction on the Cheyennes unique door hinge style hub when the mechanical control gyro is removed, with the implicit assumption...
Topics: DTIC Archive, Vocke,Robert III D, AMRDEC Redstone Arsenal United States, HELICOPTERS, WIND TUNNEL...
This report focuses on one of the most prominent flow features of the hovering rotor wake, the close interaction of the tip vortex with a following blade. Such vortex interactions are fundamental determinants of rotor performance, loads, and noise. Yet, they are not completely understood, largely due to the lack of sufficiently comprehensive experimental data. The present study aims to perform such comprehensive measurements, not on hovering helicopter rotors (which hugely magnifies test...
Topics: DTIC Archive, Bhagwat,Mahendra J, AMRDEC Redstone Arsenal United States, Trailing vortices, wind...
The slipstream effect of a transport aircraft with four turbo-propeller engines is studied by wind tunnel force test and seven-hole probe technique. The lift curve slope with slipstream increases by about 7% at typical climb condition. The zero lift drag coefficient increases by 19 and 76 drag counts at typical cruise and climb conditions respectively compared with non-slipstream condition, while the induced drag factor has a slightly decreasing trend. With slipstream effect, the pitching...
Topics: DTIC Archive, RMIT University Melbourne Australia, aircrafts, wind tunnels, wind tunnel tests,...
This paper highlights the technology development of two flow control concepts for aircraft drag reduction. The NASA Environmentally Responsible Aviation (ERA) project worked with Boeing to demonstrate these two concepts on a specially outfitted Boeing 757 ecoDemonstrator during the spring of 2015. The first flow control concept used Active Flow Control (AFC) to delay flow separation on a highly deflected rudder and increase the side force that it generates. This may enable a smaller vertical...
Topics: 1e229fe5b7284965a153b0f761643383, Alexander, Michael G., Andino, Marlyn Y., Boeing Co., Eppink,...
Experimental techniques to measure rotorcraft aerodynamic performance are widely used. However, most of them are either unable to capture interference effects from bodies, or require an extremely large computational budget. The objective of the present research is to develop an XV-15 Tilt Rotor Research Aircraft rotor model for investigation of wind tunnel wall interference using a novel Computational Fluid Dynamics (CFD) solver for rotorcraft, RotCFD. In RotCFD, a mid-fidelity URANS solver is...
Topics: NASA Technical Reports Server (NTRS), TILT ROTOR AIRCRAFT, WIND TUNNEL TESTS, COMPUTATIONAL FLUID...
Increased fuel costs, heightened environmental protection requirements, and noise abatement continue to place drag reduction at the forefront of aerospace research priorities. Unfortunately, shortfalls still exist in the fundamental understanding of boundary-layer airflow over aerodynamic surfaces, especially regarding drag arising from skin friction. For example, there is insufficient availability of instrumentation to adequately characterize complex flows with strong pressure gradients, heat...
Topics: NASA Technical Reports Server (NTRS), DRAG MEASUREMENT, FLEXIBILITY, SHEAR STRESS, BOUNDARY LAYER...
This paper contains a collection of some results of four individual studies presenting calculated numerical values for airfoil aerodynamic stability derivatives in unseparated inviscid incompressible flow due separately to angle-of-attack, pitch rate, flap deflection, and airfoil camber using a discrete vortex method. Both steady conditions and oscillatory motion were considered. Variables include the number of vortices representing the airfoil, the pitch axis / moment center chordwise...
Topics: NASA Technical Reports Server (NTRS), AERODYNAMIC COEFFICIENTS, AERODYNAMIC STABILITY, AIRFOILS,...
This paper presents detailed description of a novel CFD procedure and comparison of its solution results to that obtained by other available CFD codes as well as actual flight and wind tunnel test data pertaining to the GIII aircraft, currently undergoing flight testing at AFRC.
Topics: NASA Technical Reports Server (NTRS), COMPUTATIONAL FLUID DYNAMICS, FLIGHT TESTS, WIND TUNNEL...
This paper presents detailed description of a novel CFD procedure and comparison of its solution results to that obtained by other available CFD codes as well as actual flight and wind tunnel test data pertaining to the GIII aircraft, currently undergoing flight testing at AFRC.
Topics: NASA Technical Reports Server (NTRS), COMPUTATIONAL FLUID DYNAMICS, NUMERICAL ANALYSIS, FLIGHT...
The presentation will begin with a brief introduction to the NASA Glenn Research Center as well as an overview of how aircraft engine noise research fits within the organization. Some of the NASA programs and projects with noise content will be covered along with the associated goals of aircraft noise reduction. Topics covered within the noise research being presented will include noise prediction versus experimental results, along with engine fan, jet, and core noise. Details of the acoustic...
Topics: NASA Technical Reports Server (NTRS), JET FLOW, JET AIRCRAFT NOISE, ENGINE NOISE, ACOUSTIC...
This report describes the work conducted under NASA funding for the Boeing N+2 Supersonic Experimental Validation project to experimentally validate the conceptual design of a supersonic airliner feasible for entry into service in the 2018 -to 2020 timeframe (NASA N+2 generation). The primary goal of the project was to develop a low-boom configuration optimized for minimum sonic boom signature (65 to 70 PLdB). This was a very aggressive goal that could be achieved only through integrated...
Topics: NASA Technical Reports Server (NTRS), COMMERCIAL AIRCRAFT, TRANSPORT AIRCRAFT, SUPERSONIC...
ADEPT is an atmospheric entry architecture for missions to most planetary bodies with atmospheres: Current Technology development project funded under STMD Game Changing Development Program (FY12 start); stowed inside the launch vehicle shroud and deployed in space prior to entry; low ballistic coefficient (less than 50 kilograms per square meter) provides a benign deceleration and thermal environment to the payload; High-temperature ribs support three dimensional woven carbon fabric to...
Topics: NASA Technical Reports Server (NTRS), ATMOSPHERIC ENTRY, DEPLOYMENT, AERODYNAMIC HEATING, RIBS...
The objective of this project was to conduct additive manufacturing to produce aircraft engine components by Fused Deposition Modeling (FDM), using commercially available polyetherimides - Ultem 9085 and experimental Ultem 1000 mixed with 10 percent chopped carbon fiber. A property comparison between FDM-printed and injection-molded coupons for Ultem 9085, Ultem 1000 resin and the fiber-filled composite Ultem 1000 was carried out. Furthermore, an acoustic liner was printed from Ultem 9085...
Topics: NASA Technical Reports Server (NTRS), ADDITIVES, ADDITIVE MANUFACTURING, POLYMER MATRIX COMPOSITES,...
The study of noise from a two-shaft contra-rotating open rotor (CROR) is challenging since the shafts are not phase locked in most cases. Consequently, phase averaging of the acoustic data keyed to a single shaft rotation speed is not meaningful. An unaligned spectrum procedure that was developed to estimate a signal coherence threshold and reveal concealed spectral lines in turbofan engine combustion noise is applied to fan and CROR acoustic data in this paper (also available as...
Topics: NASA Technical Reports Server (NTRS), SIGNAL PROCESSING, BROADBAND, ACOUSTIC PROPERTIES, TURBOPROP...
No abstract available
Topics: NASA Technical Reports Server (NTRS), AEROCAPTURE, WIND TUNNEL TESTS, ATMOSPHERIC ENTRY,...
Several advances were made under this task during FY15, the first year of this effort. A portion of the task effort focused on HIFiRE-5. For this work, new capabilities in ground test and in flight data analysis were developed. Also, as a necessary precursor to wind tunnel tests on boundary layer transition on the leeside of a cone at angle of attack, extensive computations were undertaken to understand the zero angle of attack instability behavior. Although not directly related to the topic of...
Topics: DTIC Archive, AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH AEROSPACE SYSTEMS DIRECTORATE,...
Experimental aerodynamic investigations of the NASA Common Research Model have been conducted in the NASA Langley National Transonic Facility, the NASA Ames 11-ft wind tunnel, and the European Transonic Wind Tunnel. In the NASA Ames 11-ft wind tunnel, data have been obtained at only a chord Reynolds number of 5 million for a wing/body/tail = 0 degree incidence configuration. Data have been obtained at chord Reynolds numbers of 5, 19.8 and 30 million for the same configuration in the National...
Topics: NASA Technical Reports Server (NTRS), COMPARISON, INTERNATIONAL COOPERATION, WIND TUNNEL TESTS,...
The study of noise from a two-shaft contra-rotating open rotor (CROR) is challenging since the shafts are not phase locked in most cases. Consequently, phase averaging of the acoustic data keyed to a single shaft rotation speed is not meaningful. An unaligned spectrum procedure that was developed to estimate a signal coherence threshold and reveal concealed spectral lines in turbofan engine combustion noise is applied to fan and CROR acoustic data in this paper.
Topics: NASA Technical Reports Server (NTRS), SIGNAL PROCESSING, BROADBAND, ACOUSTIC PROPERTIES, ROTATING...
As part of a program to develop a systematic method to test and quantify Individual Protective Equipment effectiveness, a methodology was developed to test component (sleeve) specimens at elevated wind speeds in the Naval Aerodynamic Test Facility wind tunnel. Tests were conducted to determine the azimuthal pressure characteristics of a circular cylinder with a simulated fabric sleeve. A support screen was placed between the fabric and the circular cylinder to create an idealized flow condition...
Topics: DTIC Archive, NAVAL AIR WARFARE CENTER AIRCRAFT DIV PATUXENT RIVER MD, *OPERATIONAL EFFECTIVENESS,...
NASA maintains twelve major wind tunnels at three field centers capable of providing flows at 0.1 M 10 and unit Reynolds numbers up to 45106m. The maintenance and enhancement of these facilities is handled through a unified management structure under NASAs Aeronautics and Evaluation and Test Capability (AETC) project. The AETC facilities are; the 11x11 transonic and 9x7 supersonic wind tunnels at NASA Ames; the 10x10 and 8x6 supersonic wind tunnels, 9x15 low speed tunnel, Icing Research Tunnel,...
Topics: NASA Technical Reports Server (NTRS), WIND TUNNELS, COMPUTATIONAL FLUID DYNAMICS, VELOCITY...
Grit, trip tape, or trip dots are routinely applied on the leading-edge regions of the fuselage, wings, tails or nacelles of wind tunnel models to trip the flow from laminar to turbulent. The thickness of the model's boundary layer is calculated for nominal conditions in the wind tunnel test to determine the effective size of the trip dots, but the flow over the model may not transition as intended for runs with different flow conditions. Temperature gradients measured with an infrared camera...
Topics: NASA Technical Reports Server (NTRS), INFRARED IMAGERY, INFRARED RADIATION, BOUNDARY LAYER...
Reducing endwall and tip secondary flow losses will be a key enabler for the next generation of commercial and military air transport and will be an improvement on the state-of-the-art in turbine loss reduction strategies. The objective of this research is three-fold: 1) To improve understanding of endwall secondary flow and tip clearance losses 2) To develop novel technologies to mitigate these losses and test them in low-speed cascade and rig environments 3) To validate predictive tools To...
Topics: NASA Technical Reports Server (NTRS), BLADE TIPS, UNSTEADY FLOW, SECONDARY FLOW, FLOW DISTRIBUTION,...
A numerical, and experimental investigation to study the effects of flow distortion on a Mass Flow Plug (MFP) used to control and measure mass-flow during an inlet test has been conducted. The MFP was first calibrated using the WIND-US flow solver for uniform (undistorted) inflow conditions. These results are shown to compare favorably with an experimental calibration under similar conditions. The effects of distortion were investigated by imposing distorted flow conditions taken from an actual...
Topics: NASA Technical Reports Server (NTRS), FLOW DISTORTION, MASS FLOW, PLUGS, CALIBRATING, SUPERSONIC...
A plume and shock interaction study was developed to collect data and perform CFD on a configuration where a nozzle plume passed through the shock generated from the wing or tail of a supersonic vehicle. The wing or tail was simulated with a wedge-shaped shock generator. Three configurations were analyzed consisting of two strut mounted wedges and one propulsion pod with an aft deck from a low boom vehicle concept. Research efforts at NASA were intended to enable future supersonic flight over...
Topics: NASA Technical Reports Server (NTRS), SUPERSONIC AIRCRAFT, PLUMES, SHOCK WAVE INTERACTION, SONIC...
Presentation will an overview of NASA Armstrong's store separation capabilities and how they have been applied recently. Objective of the presentation is to brief Generation Orbit and other potential partners on NASA Armstrong's store separation capabilities. It will include discussions on the use of NAVSEP and Cart3D, as well as some Python scripting work to perform the analysis, and a short overview of this methodology applied to the Towed Glider Air Launch System. Collaboration with...
Topics: NASA Technical Reports Server (NTRS), EXTERNAL STORE SEPARATION, TRAJECTORY ANALYSIS, AIR...
NASA's Space Launch System (SLS) uses four clustered liquid rocket engines along with two solid rocket boosters. The interaction between all six rocket exhaust plumes will produce a complex and severe thermal environment in the base of the vehicle. This work focuses on a recent 2% scale, hot-fire SLS base heating test. These base heating tests are short-duration tests executed with chamber pressures near the full-scale values with gaseous hydrogen/oxygen engines and RSRMV analogous solid...
Topics: NASA Technical Reports Server (NTRS), LIQUID PROPELLANT ROCKET ENGINES, BOOSTER ROCKET ENGINES,...
Near-field acoustic power level analysis of F31A31 open rotor model has been performed to determine its noise characteristics at simulated cruise flight conditions. The non-proprietary parts of the test data obtained from experiments in the 8x6 supersonic wind tunnel were provided by NASA-Glenn Research Center. The tone and broadband components of total noise have been separated from raw test data by using a new data analysis tool. Results in terms of sound pressure levels, acoustic power...
Topics: NASA Technical Reports Server (NTRS), NEAR FIELDS, PROP-FAN TECHNOLOGY, CRUISING FLIGHT, FLIGHT...
Computational fluid dynamic predictions of surface pressures resulting from lateral jet injection into a Mach 3 supersonic crossflow from a cone-cylinder-flare missile are compared with wind tunnel data. Predictions of a sonic, multispecies, hot-gas jet using real-gas methodology are compared with predictions of a cold-gas jet and a hot, nonreacting jet using the ideal-gas assumption. An evaluation of 9 turbulence models is performed to determine their ability to accurately predict the surface...
Topics: DTIC Archive, ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD WEAPONS AND MATERIALS RESEARCH...
Determining the adverse aerodynamic effects due to ice accretion often relies on dry-air wind-tunnel testing of artificial, or simulated, ice shapes. Recent developments in ice-accretion documentation methods have yielded a laser-scanning capability that can measure highly three-dimensional (3-D) features of ice accreted in icing wind tunnels. The objective of this paper was to evaluate the aerodynamic accuracy of ice-accretion simulations generated from laser-scan data. Ice-accretion tests...
Topics: NASA Technical Reports Server (NTRS), PROVING, THREE DIMENSIONAL MODELS, ICE FORMATION, ENVIRONMENT...
Lockheed Martin Aeronautics Company (LM), working in conjunction with General Electric Global Research (GE GR) and Stanford University, executed a 19 month program responsive to the NASA sponsored "N+2 Supersonic Validation: Advanced Concept Studies for Supersonic Commercial Transports Entering Service in the 2018-2020 Period" contract. The key technical objective of this effort was to validate integrated airframe and propulsion technologies and design methodologies necessary to...
Topics: NASA Technical Reports Server (NTRS), SUPERSONIC COMMERCIAL AIR TRANSPORT, AIRFRAMES, PROPULSION...
Characterization of flight vehicle unsteady aerodynamics is often studied via large scale wind tunnel testing. Boundary layer noise is measured by miniature pressure transducers installed in a model. Noise levels (2-5 dB ref. 20 µPa) can be induced when transducer is mounted out of flush with model outer surface. This effect must be minimized to accurately determine aerodynamically induced acoustic environments.
Topics: NASA Technical Reports Server (NTRS), TRANSDUCERS, UNSTEADY AERODYNAMICS, WIND TUNNEL TESTS,...
No abstract available
Topics: NASA Technical Reports Server (NTRS), AERODYNAMIC NOISE, BROADBAND, FAN BLADES, NOISE GENERATORS,...
The authors provide a brief overview of the classic tonal screech noise problem created by underexpanded supersonic jets, briefly describing the fluid dynamic-acoustics feedback mechanism that has been long established as the basis for this well-known aeroacoustics problem. This is followed by a description of the Long Penetration Mode (LPM) supersonic underexpanded counterflowing jet phenomenon which has been demonstrated in several wind tunnel tests and modeled in several computational fluid...
Topics: NASA Technical Reports Server (NTRS), AERODYNAMIC NOISE, SUPERSONIC JET FLOW, SUPERSONIC FLOW,...
A transonic flow field about a Space Launch System (SLS) configuration was simulated with the Fully Unstructured Three-Dimensional (FUN3D) computational fluid dynamics (CFD) code at wind tunnel conditions. Unsteady, time-accurate computations were performed using second-order Delayed Detached Eddy Simulation (DDES) for up to 1.5 physical seconds. The surface pressure time history was collected at 619 locations, 169 of which matched locations on a 2.5 percent wind tunnel model that was tested in...
Topics: NASA Technical Reports Server (NTRS), COMPUTATIONAL FLUID DYNAMICS, FLOW DISTRIBUTION, DIMENSIONAL...
An advanced form of background subtraction is presented and applied to aeroacoustic wind tunnel data. A variant of this method has seen use in other fields such as climatology and medical imaging. The technique, based on an eigenvalue decomposition of the background noise cross-spectral matrix, is robust against situations where isolated background auto-spectral levels are measured to be higher than levels of combined source and background signals. It also provides an alternate estimate of the...
Topics: NASA Technical Reports Server (NTRS), BACKGROUND NOISE, SUBTRACTION, AEROACOUSTICS, WIND TUNNEL...
The Hypersonic International Flight Research Experimentation (HIFiRE) program is a hypersonic flight test program executed by the Air Force Research Laboratory (AFRL) and Australian Defence Science and Technology Organisation (DSTO). This flight contained a cylinder-flare induced shock boundary layer interaction (SBLI). Computations of the interaction were conducted for a number of times during the ascent. The DPLR code used for predictions was calibrated against ground test data prior to...
Topics: NASA Technical Reports Server (NTRS), HYPERSONIC FLIGHT, TURBULENT BOUNDARY LAYER, SHOCK LAYERS,...
An experimental, computational and theoretical investigation was carried out to study the aerodynamic loads acting on a relatively thick NACA 0018 airfoil when subjected to pitching and surging, individually and synchronously. Both pre-stall and post-stall angles of attack were considered. Experiments were carried out in a dedicated unsteady wind tunnel, with large surge amplitudes, and airfoil loads were estimated by means of unsteady surface mounted pressure measurements. Theoretical...
Topics: NASA Technical Reports Server (NTRS), AIRFOILS, LEADING EDGES, TRAILING EDGES, PITCHING MOMENTS,...
The 9- by 15-Foot Low Speed Wind Tunnel is an acoustic testing facility with a long history of aircraft propulsion noise research. Due to interest in renovating the facility to support future testing of advanced quiet engine designs, a study was conducted to document the background noise level in the facility and investigate the sources of contaminating noise. The anechoic quality of the facility was also investigated using an interrupted noise method. The present report discusses these aspects...
Topics: NASA Technical Reports Server (NTRS), ACOUSTICS, LOW SPEED WIND TUNNELS, NOISE INTENSITY,...
A detailed assessment of the acoustic performance of several noise reduction concepts for aircraft flaps and landing gear is presented. Consideration is given to the best performing concepts within the suite of technologies that were evaluated in the NASA Langley Research Center 14- by 22-Foot Subsonic Tunnel using an 18 percent scale, semi-span, high-fidelity Gulfstream aircraft model as a test bed. Microphone array measurements were obtained with the model in a landing configuration (flap...
Topics: NASA Technical Reports Server (NTRS), FLAPS (CONTROL SURFACES), LANDING GEAR, NOISE (SOUND), NOISE...