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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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51 records · Page 3
All sourcesNASA NTRSDOE OSTI
NASA NTRSDate not supplied

Summary of the NASA Semi-Span High-Lift Common Research Model Wind Tunnel Test at the QinetiQ 5-Metre Low-Speed Facility

A summary and selected results from experimental testing of the NASA 10% scale semi-span High-Lift Common Research Model (CRM-HL) at the QinetiQ 5m (5mWT) pressurized low-speed wind tunnel are presented. There were many objectives of this test, the primary being to define a set of reference configurations for dissemination and use within the CRM-HL ecosystem, one in the landing configuration and one in the takeoff configuration. A database of force, moment, pressure and surface flow visualization data was collected to support several objectives: aerodynamic sensitivity to high-lift device positioning, Reynolds number effects on configuration selection, isolation of the effects of various components of the reference configuration e.g. landing gear, nacelle, horizontal tail, etc., and limited repeatability data for uncertainty quantification assessment. Some results were compared to limited data collected at the NASA Langley Research Center 14x22 wind tunnel to assess half-model effects and facility differences. Half-model effects were further studied with use of floor blowing to change boundary layer profile and assess effects on model aerodynamics. Flow visualization data were gathered with fluorescent mini-tufts and UV oil. Finally, test time was spend working on the development of new Particle Image Velocimetry (PIV) and Model Deformation Measurement (MDM) capabilities at the 5mWT facility.

Ashley Evans↗
NASA NTRSDate not supplied

Unsteady Pressure Measurements on a Simplified High-Lift Configuration of the Common Research Model using Active Flow Control

The High-Lift Common Research Model (CRM-HL) is a product of the NASA Advanced Air Transport Technology (AATT) Project intended to study various high-lift aerodynamic phenomena including enhanced lift, acoustic noise generation, and optimum placement of leading and trailing-edge devices. The current study was conducted in the NASA Langley 14-by 22-Foot Subsonic Tunnel (14x22) for the purpose of evaluating enhanced lift through the use of active flow control (AFC). The current paper documents the effect of sweeping-jet actuation combined with steady blowing on a simplified high-lift configuration using unsteady pressure measurements. The time-series parameters for the measurements are documented as well as the data acquisition system used to acquire the data. An uncertainty analysis will be presented in order to document the system performance and provide an estimate of the data quality. Repeatability of the data will be shown along with trends associated with model angle of attack, and also those associated with changes in the nozzle pressure ratio (NPR) of the AFC system.

Active Flow Control↗
NASA NTRSDate not supplied

Development of the 10% NASA CRM High-Lift Common Research Model (CRM-HL)

A 10%-scale Common Research Model-high lift version (CRM-HL) was developed to support extensive experimental investigations in the areas of active flow control, control surface optimization for landing and take-off, acoustic technology development, and computational fluid dynamics code validation to name a few. The CRM-HL was designed to have modular components that will enable the model to be tested in the following three forms: (1) conventional high-lift (CHL) configuration, (2) Active Flow Control (AFC) enabled simple hinged flap high-lift (SHL) configuration, and (3) CHL configuration with noise reduction treatments for the slats and/or the flaps. This paper describes the design, analysis, and fabrication of the CRM-HL for testing in the NASA Langley Research Center (LaRC) 14 by 22-Foot Subsonic Tunnel (14x22) and other wind tunnels as deemed appropriate by the research community such as the Qinetiq 5 Meter tunnel.

Jared S. Fell↗
NASA NTRSDate not supplied

Model Deformation Measurements by Stereo Photogrammetry at NASA Ames Research Center

At this meeting I will present an overview of tests where my AOX colleagues and I used stereo photogrammetry to measure model deformations. I will discuss in greater detail two recent tests: the Transonic Truss-Braced Wing in the 11x11 ft TWT and a Rotor in Forward Flight in the LaRC 14x22 ft WT. I will conclude with a discussion of lessons learned and future plans.

Photogrammetry↗
NASA NTRS2024

Completion of Dragonfly PPF Testing in the NFAC 80x120-Foot Wind Tunnel

The Dragonfly entry, descent, and landing team (JHU-APL, NASA Langley Research Center, NASA Ames Research Center, Sikorsky Aircraft) recently completed testing in the National Full-Scale Aerodynamics Complex (NFAC) 80x120-Foot Wind Tunnel. The facility is located at NASA Ames Research Center and is operated by the U.S. Air Force's Arnold Engineering Development Complex. The test was designed to simulate conditions of Preparation for Powered (PPF), an approximately 10-minute period during which the Lander is posed in front of the Backshell at low subsonic airspeeds, all under the main parachute, and the rotors are used to null residual Lander yaw rates prior to release i. e. de-spin. The Lander (approximately 50% scale) that previously was tested in the NASA Langley 14x22 Wind Tunnel in 2023 was used for the NFAC test with a new Backshell designed and fabricated specifically for NFAC. This memorandum summarizes execution of the test: objective, facility and models, instrumentation and data products, test procedure, and completed test matrix. Other future documents will include a test report (JHU-APL) and documentation of data processing/analysis and computational fluid dynamics (CFD) comparisons to test data (Sikorsky).

Dragonfly↗
NASA NTRSDate not supplied

Low-Speed Testing of the 5.2% Semispan CRM-HL in the DNW-NWB Wind Tunnel

In this paper the wind tunnel test of the 5.2% CRM-HL in the DNW-NWB low speed wind tunnel is described. The tunnel test campaign is settled in the DLR project ADaMant, in which it is of interest to generate qualitative data for CFD validation to improve the predictive accuracy, efficiency, and usability of physical modeling in CFD codes at the borders of the flight envelope. Different configurations of the CRM-HL were tested in a closed as well as in an open test section of the wind tunnel. Several measurement techniques were used to generate validation data including forces and moments, pressures, flow visualization with tufts and oil painting, and infrared thermography for boundary layer transition detection. The evaluation of the results focuses on these techniques in the closed test section. The test comprises Mach numbers from 0.15 to 0.23 and Reynolds numbers from 1.2x10 6 to 1.2x10 6 . Some results are also compared to data from the NASA Langley Research Center 14x22 Foot wind tunnel to assess the repeatability of measurements of the same model in different wind tunnels.

DLR↗
NASA NTRSDate not supplied

NASA Contributions to the High Lift Common Research Model Ecosystem

As part of the High Lift Common Research Model (CRM-HL) ecosystem, NASA has designed and built two CRM-HL models. The first model is a 5.2% scale semispan model that has been tested in the NASA Langley 14- by 22-Foot Subsonic Wind Tunnel (14x22), the low-speed wind tunnel DNW-NWB in Germany and in the National Transonic Facility (NTF) at NASA Langley Research Center. Information on the NASA tests that will include model details, test methods and some test data will be presented in the final document. The second model is a 2.7% scale model that will also be tested in the NTF in both full span and semispan configurations. Information on the design and fabrication of this model will be included in the final document.

Melissa Rivers↗
NASA NTRSDate not supplied

NASA 5.2%-Scale High Lift Common Research Model (CRM-HL) Test in the National Transonic Facility (NTF)

Problem: Predicting CL,max and assessing transition, turbulence models, and Reynolds number effect predictions in CFD requires wind tunnel data for comparison. Objective: Expand the CFD validation database by running multiple models designed using the same reference geometry in various wind tunnels around the world. The wind tunnel data and model geometry will be open source to allow for CFD validation use. Approach: Run the NASA 5.2%-scale High Lift Common Research Model (CRM-HL) semi-span model at the National Transonic Facility (NTF). Test the model at chord Reynolds numbers (Rec) between 1.6 million and 30 million and at varying Q/Es to assess Reynolds number effects and aeroelasticity affects on the model, while collecting force and moment, pressure and wing deformation data. Test the model with ice shapes installed on the leading edges. Results: Ran eight model configurations, including four landing, two landing with ice shapes installed, and two takeoff configurations. Ran in air (120°F) and nitrogen operations (-50°F, -180°F and -250°F) at 7 different chord Reynolds numbers. The data compare well with previous tests of the same model at DLR (The Germany Aerospace Center) and the 14- by 22-Foot Subsonic Tunnel (14x22). Significance: Provided valuable high Reynolds number data on a high lift configuration to the worldwide research community. Provide icing data at flight Reynolds number to the research community.

CRM-HL↗
NASA NTRSDate not supplied

Testing of High-Lift Common Research Model at Takeoff Configurations

The 10% scale High-Lift Common Research Model (CRM-HL) was tested in the NASA Langley 14- by 22-Foot Subsonic Tunnel (14x22) in support of the NASA Advanced Air Transport Technology (AATT) Project. The main objective of the wind tunnel test was to improve the aerodynamic performance of a representative aircraft model during takeoff operations using localized active flow control (AFC). This approach involves the application of AFC concepts locally to a relatively small region; therefore, it has the potential to cause minimal architectural change to current aircraft configurations. In addition, the power requirements of localized AFC could be supplied with onboard air resources. Recent exploratory studies identified the aileron as a target area for improving lift-to-drag ratio using localized AFC concepts. The idea is to deflect the ailerons beyond their nominal deflection angles and use AFC to reduce flow separation that occurs at larger aileron deflections. Several AFC concepts with different configurations were evaluated with the goal of achieving high-lift performance improvement. The assessment of AFC configurations is reported in a companion paper. The focus of the current paper is to report the data relevant to the CRM-HL takeoff configurations and establish a reference case for localized AFC application. Three takeoff configurations —reference, nominal, and high-lift improved—are documented. These takeoff configurations are obtained by varying aileron deflection. Wind tunnel measurements including surface static pressures and force and moment data are presented. In addition, surface tuft flow visualization, mainly on the aileron, is provided to understand the flow characteristics developed over the aileron during takeoff.

Lift-to-Drag↗
NASA NTRSDate not supplied

Testing of High-Lift Common Research Model at Takeoff Configurations

The 10% scale High-Lift Common Research Model (CRM-HL) was tested in the NASA Langley 14- by 22-Foot Subsonic Tunnel (14x22) in support of the NASA Advanced Air Transport Technology (AATT) Project. The main objective of the wind tunnel test was to improve the aerodynamic performance of a representative aircraft model during takeoff operations using localized active flow control (AFC). This approach involves the application of AFC concepts locally to a relatively small region; therefore, it has the potential to cause minimal architectural change to current aircraft configurations. In addition, the power requirements of localized AFC could be supplied with onboard air resources. Recent exploratory studies identified the aileron as a target area for improving lift-to-drag ratio using localized AFC concepts. The idea is to deflect the ailerons beyond their nominal deflection angles and use AFC to reduce flow separation that occurs at larger aileron deflections. Several AFC concepts with different configurations were evaluated with the goal of achieving high-lift performance improvement. The assessment of AFC configurations is reported in a companion paper. The focus of the current paper is to report the data relevant to the CRM-HL takeoff configurations and establish a reference case for localized AFC application. Three takeoff configurations —reference, nominal, and high-lift improved—are documented. These takeoff configurations are obtained by varying aileron deflection. Wind tunnel measurements including surface static pressures and force and moment data are presented. In addition, surface tuft flow visualization, mainly on the aileron, is provided to understand the flow characteristics developed over the aileron during takeoff.

Wind tunnel test↗
NASA NTRSDate not supplied

In-Tunnel Simulations of the NASA Juncture Flow Model

The effect of wind tunnel walls on the development of flow separation in the wing-fuselage juncture area is assessed using FUN3D’s overset and wind tunnel controller capabilities. The simulation data obtained from the in-tunnel runs are compared with the free-air simulations. The simulation results are also evaluated using measurements from the recently completed Phase 2 of the Juncture Flow Experiment. In general, the simulation data compared well with the measurements, however there were no significant differences in the prediction of the separation location, size, and shape, between the free-air and the in-tunnel runs. The results of this study suggest that the effects of tunnel walls on the flow separation in the juncture region are relatively small.

Juncture Flow↗
NASA NTRSDate not supplied

In-Tunnel Simulations of the NASA Juncture Flow Model

The effect of wind tunnel walls on the development of flow separation in the wing-fuselage juncture area is assessed using FUN3D’s overset and wind tunnel controller capabilities. The simulation data obtained from the in-tunnel runs are compared with the free-air simulations. The simulation results are also evaluated using measurements from the recently completed Phase 2 of the Juncture Flow Experiment. In general, the simulation data compared well with the measurements, however there were no significant differences in the prediction of the separation location, size, and shape, between the free-air and the in-tunnel runs. The results of this study suggest that the effects of tunnel walls on the flow separation in the juncture region are relatively small.

Juncture Flow↗
NASA NTRSDate not supplied

Active Flow Control Enhanced Aileron of the High-Lift Common Research Model at Takeoff Condition

An experimental investigation was conducted in the NASA Langley 14- by 22-Foot Subsonic Tunnel on the NASA 10% scale High-Lift Common Research Model (CRM-HL) to improve the high-lift aerodynamic performance of the takeoff configuration. Active flow control (AFC) was applied at the aileron hinge line to control flow separation at high aileron deflection angles ( δ a ) to increase lift-to-drag ratio (R/J). Improvements in low speed R/J can increase vehicle payload and/or range resulting in a more efficient vehicle. Aileron deflection angles of 0°, 7.5°, 16°, and 25° were investigated. Flow control was applied to the two largest aileron deflections, which are considered the high-lift (HL) improved takeoff configurations. A companion paper will discuss baseline flow characteristics of the CRM-HL at the three takeoff conditions: reference, nominal, and HL-improved. In this paper, we focus on the aerodynamic improvement obtained when AFC was applied to δ a = 16° relative to the nominal configuration, δ a = 7.5°. Multiple flow control parameters, including actuator type, spacing, and intensity, were investigated to evaluate the efficiency of the actuation system. The different AFC configurations tested were assessed with tuft visualization, steady surface pressure data, and force and moment data. The results indicated that all actuation types and spacings examined led to an increase in lift across the range of angles of attack investigated. Flow separation was mitigated with the injection of momentum at the aileron hinge line. The configurations with the smallest spacing produced the highest improvement in L/D . Steady jet actuation showed higher efficiency but similar aerodynamic performance when compared to the sweeping jet actuators. This work was performed in support of the NASA Advanced Air Transport Technology (AATT) Project.

High-Lift Common Research Model↗
NASA NTRSDate not supplied

Active Flow Control Enhanced Aileron of the High-Lift Common Research Model at Takeoff Condition

An experimental investigation was conducted in the NASA Langley 14- by 22-Foot Subsonic Tunnel on the NASA 10% scale High-Lift Common Research Model (CRM-HL) to improve the high-lift aerodynamic performance of the takeoff configuration. Active flow control (AFC) was applied at the aileron hinge line to control flow separation at high aileron deflection angles to increase lift-to-drag ratio (L/D). Improvements in low speed L/D can increase vehicle payload and/or range resulting in a more efficient vehicle. Aileron deflection angles of 0°, 7.5°, 16°, and 25° were investigated. Flow control was applied to the two largest aileron deflections, which are considered the high-lift (HL) improved takeoff configurations. A companion paper will discuss baseline flow characteristics of the CRM-HL at the three takeoff conditions: reference, nominal, and HL-improved. In this paper, we focus on the aerodynamic improvement obtained when AFC was applied to an aileron deflected at 16° relative to the nominal configuration of 7.5° deflection. Multiple flow control parameters, including actuator type, spacing, and intensity, were investigated to evaluate the efficiency of the actuation system. The different AFC configurations tested were assessed with tuft visualization, steady surface pressure data, and force and moment data. The results indicated that all actuation types and spacings examined led to an increase in lift across the range of angles of attack investigated. Flow separation was mitigated with the injection of momentum at the aileron hinge line. The configurations with the smallest spacing produced the highest improvement in L/D. Steady jet actuation showed higher efficiency but similar aerodynamic performance when compared to the sweeping jet actuators. This work was performed in support of the NASA Advanced Air Transport Technology (AATT) Project.

CRM-HL↗