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At least 721 records · Page 40
All sourcesNASA NTRSDOE OSTI
NASA NTRS2012

Validation of US3D for Capsule Aerodynamics using 05-CA Wind Tunnel Test Data

RANS is ill-suited for analysis of these problems. For transonic and supersonic cases, US3D shows fairly good agreement using DES across all cases. Separation prediction and resulting backshell pressure are problems across all portions of this analysis. This becomes more of an issue at lower Mach numbers: .Stagnation pressures not as large - wake and backshell are more significant .Errors on shoulder act on a large area - small discrepancies manifest as large changes Subsonic comparisons are mixed with regard to integrated loads and merit more attention. Dominant unsteady behavior (wake shedding) resolved well, though.

Schwing, Alan↗
NASA NTRS1943

Wind-Tunnel Tests of an NACA 44R-Series Tapered Wing with a Straight Trailing Edge and a Constant-Chord Center Section

As part of a general investigation in the NACA 19-foot pressure tunnel to determine stall characteristics and effectiveness of high-lift devices on wings of various sections, tests were made of a tapered. wing having NACA 44R-series airfoil sections. Lift, drag, pitching-moment, and stall characteristics were determined at a Reynolds number of 4,850,000 for the plain wing and for the wing with partial-and with full-span split flaps. The stall progressed slowly over The plain wing; a gradual loss of lift for angles of attack up to and beyond that for the maximum lift coefficient resulted. As Compared with the stall of the plain wing, the initial stall of the wing with either partial-span or full-span flaps deflected occurred at a higher angle of attack and the stall progressed much more rapidly. The maximum lift coefficients at a Reynolds number of 4,850,000 were 1.35 for the plain wing, 2.25 for the wing with partial-span flaps at 60 deg, and 2.67 for the wing with full-span flaps at 60 deg. The positions of the aerodynamic center, in terms of mean chords back of the leading edge of the root section, were approximately 0.458 with no flaps, 0.483 with partial-span flaps at 60 deg, and 0.498 with full-span flaps at 60 deg.

Neely, Robert H.↗
NASA NTRS1945

High-Speed Wind-Tunnel Tests of Dive-Recovery Flaps of a 0.3-Scale Model of the P-47D Airplane

This report presents the results of tests of a 0.3-Scale Model of the Republic P-47D airplane equipped with several dive-recovery flaps. Results are presented showing the drag coefficient and pitching-moment coefficient produced by the various flaps. The results of computations made to predict the normal acceleration due to deflecting the flaps in a vertical dive, the lift coefficient of the tail required for balance, and the relative magnitudes of the various factors which contribute to the pitching-moment increment are also given.

William T Hamilton↗
NASA NTRS1942

Wind-Tunnel Tests of 1/6-Scale Model of Republic P-47C Airplane with External Wing Tank

In order to increase the range of the Republic P-47C airplane for ferrying purposes it has been proposed that the airplane be equipped with streamlined external wing tanks. This report presents the aerodynamic effect of such wing tanks as determined from tests of a l/6-scale model in the 7- by 10-foot tunnel of the Langley Memorial Aeronautical Laboratory.

Marvin J Schuldenfrei↗
NASA NTRS2015

Nano-ADEPT Aeroloads Wind Tunnel Test

Analysis completed since the test suggests that all test objectives were met– This claim will be verified in the coming weeks as the data is examined further– Final disposition of test objective success will be documented in a final reportsubmitted to NASA stakeholders (early August 2015)– Expect conference paper in early 2016• Data products and observations made during testing will be used to refinecomputational models of Nano-ADEPT• Carbon fabric relaxed from its pre-test state during the test– System-level tolerance for relaxation will be driven by destination-specific andmission-specific aerothermal and aerodynamic requirements• Bonus experiment of asymmetric shape demonstrates that an asymmetricdeployable blunt body can be used to generate measureable lift– With a strut actuation system and a robust GN&C algorithm, this effect could beused to steer a blunt body at hypersonic speeds to aid precision landing

atmospheric entry↗
NASA NTRS2016

Status of the KTH-NASA Wind-Tunnel Test for Acquisition of Transonic Nonlinear Aeroelastic Data

This paper presents a status report on the collaboration between the Royal Institute of Technology (KTH) in Sweden and the NASA Langley Research Center regarding the design, fabrication, modeling, and testing of a full-span lighter configuration in the Transonic Dynamics Tunnel (TDT). The goal of the test is to acquire transonic limit-cycle- oscillation (LCO) data, including accelerations, strains, and unsteady pressures. Finite element models (FEMs) and aerodynamic models are presented and discussed along with results obtained to date.

Silva, Walter A.↗
NASA NTRS2019

Wind Tunnel Testing of Active Flow Control on High-Lift Common Research Model

A 10%-scale high-lift version of the Common Research Model (CRM-HL) and an Active Flow Control (AFC) version of the model equipped with a simple-hinged flap (CRM-SHLAFC) were successfully tested. The tests were performed in the 14- by 22-Foot Subsonic Tunnel (14x22) at the NASA Langley Research Center (LaRC). The CRM-HL has a set of 37° inboard and outboard single-element Fowler flaps. The CRM-SHL-AFC has a set of 50° inboard and 55° outboard simple-hinged flaps equipped with integrated modular AFC cartridges on the flap shoulder. Both high-lift configurations share the same 30° slats and engine nacelle. Three new types of AFC devices were examined: the Double-Row Sweeping Jets (DRSWJ), the Alternating Pulsed Jets (APJ), and the High Efficiency Low Power (HELP) actuators. The DRSWJ and the APJ actuators used two rows of unsteady jets, whereas the HELP actuators used a combination of unsteady and steady jets, to overcome strong adverse pressure gradients while minimizing the mass flow usage. Nozzle pressure ratio, mass flow consumption and the power coefficient, which takes account of both supply air pressure and mass flow usage for the actuators, were used for judging the performance efficiency of the AFC devices. A prestall lift performance degradation for the CRM-HL configuration was resolved with a properly placed nacelle chine. The configuration with nacelle chine was chosen as the representative reference conventional high-lift case for comparison with the CRMSHL- AFC. The AFC-induced lift coefficient increment (DCL) was maintained for the entire lift curve over the CRM-SHL-AFC case with no AFC for almost all flow-control cases examined. The lift curve of the reference CRM-HL have a slightly steeper slope compared to those of the CRM-SHL-AFC configurations. The HELP actuation concept was extremely effective in controlling flow separation in the “linear region” of the curves comparing lift coefficient to mass flow rate. The HELP actuation achieved a targeted DCL of 0.50 using a moderate amount of mass flow and supply air pressure. The CRM-SHL-AFC configuration equipped with HELP actuation was able to match or exceed the lift performance of the reference conventional high-lift configuration (i.e., CRM-HL equipped with a nacelle chine), thus meeting the NASA Advanced Air Transport Technology (AATT) project goal.

Lin, John C.↗
NASA NTRS2020

Wind Tunnel Testing of High Efficiency Low Power (HELP) Actuation for Active Flow Control

A High Efficiency Low Power (HELP) methodology has been successfully developed and tested on an active flow control (AFC) version of the 10%-scale high-lift Common Research Model (CRM-HL) at the NASA Langley Research Center 14- by 22-Foot Subsonic Tunnel (14x22). The AFC variant of the CRM-HL, designated as CRM-SHL-AFC, was integrated with modular HELP actuator cartridges on the shoulder of its highly deflected (≥50°) simplehinged flaps. A reference conventional CRM-HL configuration equipped with Fowler flaps and a nacelle chine was chosen to provide the targeted lift enhancement goals and for comparison with the results of the CRM-SHL-AFC. The current data are presented with the Transonic Wall Interference Correction System (TWICS) method applied. The HELP actuators, which use a combination of unsteady sweeping jets and steady discrete jets in tandem, were designed to overcome strong adverse pressure gradients, while minimizing the pneumatic power usage. The power coefficient (C(sub π)), which takes account of both supply air pressure and mass flow usage for the AFC actuators, is a useful parameter for judging the actuators’ performance efficiency and perhaps for scaling-up of the AFC system. Full HELP actuation coverage with a constant spanwise nozzle pressure ratio (NPR) was able to achieve the lift enhancement goals for the entire lift curve and was found to be the most effective AFC case. For the most effective case, mass flow rates greater than ~0.91 lbm/s and NPR values greater than ~1.8 (corresponding to C(sub π) = 0.18) are needed to achieve the lift enhancement goal at α = 9°, whereas mass flow rates greater than ~1.23 lbm/s and NPR values greater than ~2.3 (corresponding to C(sub π) = 0.3) are needed to achieve the lift enhancement goal at α = 17°. Surface pressure distributions indicate that the HELP actuation on the flap shoulder increased the suction pressures (and flow circulation) globally in both the streamwise and the spanwise directions, and thereby enhanced the lift over the entire high-lift system. The CRM-SHLAFC configuration equipped with HELP actuation was able to match or exceed the lift performance of the reference conventional CRM-HL, thus meeting the objective of the research.

John C Lin↗