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At least 559 records · Page 31

Experimental investigation at Mach 8 of the effects of projections and cavities on heat transfer to a model of the Viking aeroshell

An experimental investigation into the aerodynamic heating on a Mars entry vehicle shape with several types of local surface distortion is presented. The configurations tested were 0.033-scale models of a spherically blunted 70 deg half-angle cone with two protuberances of different length, representing the tube leading to the gas chromograph mass spectrometer, and two aeroshell-bioshield attachment points of different size. These models were tested at free-stream Reynolds numbers per meter of 3.7 million and 17 million over an angle-of-attack range from 0 to 18 deg in the Langley Mach 8 variable density hypersonic tunnel. The phase change-coating technique was used to measure heat transfer coefficient. The long protuberance caused more severe interference heating than the short protuberance for the same conditions. When the short projection was located close to the edge of the aeroshell, the interference heating was greater than that on the same projection when located near the vertex. A significant increase in heat transfer coefficient was measured only on the larger aeroshell-bioshield attachment point.

Creel, T. R., Jr.↗

Experimental probability density distributions for optical and infrared cross-beam units

A series of cross beam experiments for measuring meteorological parameters was conducted. Both optical and infrared sensors were tested for comparison. The test configuration and experiment identification are provided. A data report is presented for an approximate analysis of the probability density distributions of the signals from both the optical and the infared units. Two runs representing each of the two types of cross-beam units were selected for analysis. Probability density functions are also presented for the instantaneous product of the signals for each of the runs.

Huff, L. L.↗

Liquid rocket propellant feedline dynamics

An analytical and experimental study of liquid rocket propellant feedline dynamics has been performed. The analytical model, which includes the effects of turbulent flow, distributed and local compliances, bellows, side branches, and structural mounting stiffness, was verified by an experimental program. Water was used as the internal fluid and the dynamic perturbations in pressure and flow were created by a piston pulser. Measurements were made to determine the pressure perturbation amplitude and phase at the line terminal due to a sinusoidal pulser excitation. The frequency response of the various line configurations tested were compared with the computed theoretical results.

Holster, J. L.↗

Effect of exhaust nozzle configuration on aerodynamic and acoustic performance of an externally blown flap system with a quiet 6:1 bypass ratio engine

A highly suppressed TF-34 engine was used to investigate engine and flap interaction noise associated with an externally blown flap STOL powered lift system. Noise, efficiency, and velocity decay characteristics of mixed and separate flow exhaust systems including convergent, co-annular, and lobed designs were determined with the engine operating alone. Noise data were then obtained for several of the exhaust configurations with the engine blowing a wing-flap segment. Noise for both the engine alone and the engine with blown flaps showed substantial differences for the various exhaust configurations tested. The differences in observed noise are related primarily to nozzle effective exhaust velocity, flap impingement velocity, and noise spectral shape.

Samanich, N. E.↗

Electrohydrodynamically coupled Kelvin-Helmholtz instability

An inviscid model of the surface dynamics at the interface between two parallel-flowing insulating dielectric fluids, subject to a tangential electric field with a weak gradient, is developed. The two flows are oppositely directed, resulting in an electrohydrodynamically coupled Kelvin-Hemholtz instability. A simple stability criterion is used successfully to correlate experimental data obtained with a test configuration.

Perry, M. P.↗

Influence of orbital-maneuvering-system fairings and rudder flare on the transonic aerodynamic characteristics of a space shuttle orbiter

An investigation was conducted in the Langley 8-foot transonic pressure tunnel to determine the influence of orbital-maneuvering-system fairings and a flared rudder on the aerodynamic characteristics of a space shuttle-orbiter configuration. Tests were made at Mach numbers from 0.4 to 1.2, at angles of attack from -1 deg to 24 deg, at angles of sideslip of 0 deg and 5 deg, and at a Reynolds number, based on model length, of 4 million. The model with the orbital-maneuvering-system fairings had a minimum untrimmed lift-drag ratio from 7.4 to 3.4 at Mach numbers from 0.4 to 1.2 and a maximum trimmed lift-drag ratio of about 3.55 at Mach 0.8 with the rudder flared 30 deg. The directional stability was increased at Mach 0.8 and 1.2 by addition of the orbital-maneuvering-system fairings and at Mach 1.2 by flaring the rudder.

Ellison, J. C.↗

An investigation of rooftop STOL port aerodynamics

An investigation into aerodynamic problems associated with large building rooftop STOLports was performed. Initially, a qualitative flow visualization study indicated two essential problems: (1) the establishment of smooth, steady, attached flow over the rooftop, and (2) the generation of acceptable crosswind profile once (1) has been achieved. This study indicated that (1) could be achieved by attaching circular-arc rounded edge extensions to the upper edges of the building and that crosswind profiles could be modified by the addition of porous vertical fences to the lateral edges of the rooftop. Important fence parameters associated with crosswind alteration were found to be solidity, fence element number and spacing. Large scale building induced velocity fluctuations were discovered for most configurations tested and a possible explanation for their occurrence was postulated. Finally, a simple equation relating fence solidity to the resulting velocity profile was developed and tested for non-uniform single element fences with 30 percent maximum solidity.

Blanton, J. N.↗

Program to stimulate graduate training in the field of aeroacoustics

An experiment is reported to cross correlate the output of hot film probes located at various points in the flow field of a jet-blown flap with the output of microphones in the acoustic far field. Fluid dynamic measurements of the flow fields of the test configuration are reported.

Becker, R. S.↗

Aerodynamic heating to corrugation stiffened structures in thick turbulent boundary layers

The results of an experimental program to evaluate heat transfer and pressure distributions on corrugation roughened flat plates in thick turbulent boundary layers are presented. The experimental program consisted of tests in the tunnel wall boundary layers of the Langley Unitary Plan Wind Tunnel (UPWT) and Continuous Flow Hypersonic Tunnel (CFHT) at freestream Mach numbers of 2.5, 3.5, 4.5, and 10.3. Tests in the UPWT were conducted at a freestream Reynolds number/m of 10,800,000 and in the CFHT, at Reynolds numbers/m of 1,300,000 to 5,800,000. The test configurations consisted of 50.8 x 50.8 cm panels with corrugated beads of two different peak amplitudes, 0.61 and 0.29 cm. The angle of the corrugated beads relative to the flow direction was varied between 0 (aligned) and 90 deg (normal). The measured peak and average heat transfer are analyzed and correlated in terms of the bulk boundary layer, internal boundary layer, and geometric parameters.-

Brandon, H. J.↗

Experimental parametric studies of transonic T-tail flutter

Wind-tunnel tests of the T-tail of a wide-body jet airplane were made at Mach numbers up to 1.02. The model consisted of a 1/13-size scaled version of the T-tail, fuselage, and inboard wing of the airplane. Two interchangeable T-tails were tested, one with design stiffness for flutter-clearance studies and one with reduced stiffness for flutter-trend studies. Transonic antisymmetric-flutter boundaries were determined for the models with variations in: (1) fin-spar stiffness, (2) stabilizer dihedral angle (-5 deg and 0 deg), (3) wing and forward-fuselage shape, and (4) nose shape of the fin-stabilizer juncture. A transonic symmetric-flutter boundary and flutter trends were established for variations in stabilizer pitch stiffness. Photographs of the test configurations are shown.

Ruhlin, C. L.↗

Longitudinal aerodynamic characteristics of a deflected-thrust propulsive-lift transport model

A wind-tunnel investigation was conducted to determine the effect of deflecting the engine exit of a four-engine double-slotted flap transport to provide STOL performance. Longitudinal aerodynamic data were obtained at various engine exit positions and deflections. The data were obtained at three flap deflections representing cruise, take-off, and landing conditions for a range of angles of attack and various thrust coefficients. Downwash angles at the location of the horizontal tail were measured. The data are presented without analysis or discussion. Photographs of the test configurations are shown.

Hoad, D. R.↗

An investigation of the 0.0091 scale External Tank ogive nose (MSFC model 470) in the MSFC 14 inch TWT to determine the pressure distribution around the External Tank Nose (TA3F), volume 1

The model tested was a 0.0091 scale representation of the ogive nose section of the External Tank with nose cap and lightning rod and protuberances. Pressure distribution around the nose cap was determined. Pressure data were also obtained along the ogive nose. Data were obtained over an angle of attack range of + or -5 degrees and over a Mach number range of .6 to 4.96. The Reynolds number per unit length (ft.) ranged from 4.1 million to 4.96 million. There were 22 pressure ports in a single row. Circumferential positions of 0, 22.5, 45, 67.5 and 90 degrees were simulated by rotating the model. The LO2 feed line and LO2 recirculation line were simulated. The effects of the nose spike were investigated over a range of Mach numbers. The data will be useful for venting analyses. Photographs showing flow visualization of the test configuration are given.

Ramsey, P. E.↗

Results of pressure distribution tests of a 0.010-scale space shuttle orbiter model (61-0) in the NASA/ARC 3.5-foot hypersonic wind tunnel (test OH38), volume 1

Test results are presented of hypersonic pressure distributions at simulated atmospheric entry conditions. Pressure data were obtained at Mach numbers of 7.4 and 10.4 and Reynolds numbers of 3.0 and 6.5 million per foot. Data are presented in both plotted and tabulated data form. Photographs of wind tunnel apparatus and test configurations are provided.

Dye, W. H.↗

Results of an investigation of jet plume effects on a 0.010-scale model (75-OTS) of the space shuttle integrated vehicle in the 8 x 7-foot leg of the NASA/Ames unitary wind tunnel (IA82C), volume 1

The primary test objective was to define the base pressure environment of the first and second stage mated vehicle in a supersonic flow field from Mach 2.60 through 3.50 with simulated rocket engine exhaust plumes. The secondary objective was to obtain the pressure environment of the Orbiter at various vent port locations at these same freestream conditions. Data were obtained at angles of attack from -4 deg through +4 deg at zero yaw, and at yaw angles from -4 deg through +4 deg at zero angle of attack, with rocket plume sizes varying from smaller than nominal to much greater than nominal. Failed Orbiter engine data were also obtained. Elevon hinge moments and wing panel load data were obtained during all runs. Photographs of test equipment and tested configurations are shown.

Hawthorne, P. J.↗

Results of an investigation of jet plume effects on an 0.010-scale model (75-OTS) of the space shuttle integrated vehicle in the 9 x 7-foot leg of the NASA/Ames unitary wind tunnel (IA82B), volume 1

The base pressure environment was investigated for the first and second stage mated vehicle in a supersonic flow field from Mach 1.55 through 2.20 with simulated rocket engine exhaust plumes. The pressure environment was investigated for the orbiter at various vent port locations at these same freestream conditions. The Mach number environment around the base of the model with rocket plumes simulated was examined. Data were obtained at angles of attack from -4 deg through +4 deg at zero yaw, and at yaw angles from -4 deg through +4 deg at zero angle of attack, with rocket plume sizes varying from smaller than nominal to much greater than nominal. Failed orbiter engine data were also obtained. Elevon hinge moments and wing panel load data were obtained during all runs. Photographs of the tested configurations are shown.

Hawthorne, P. J.↗

Results of an experimental investigation to determine separation characteristics for the Orbiter/747 using a 0.0125-scale model (48-0 AX1318I-1 747) in the Ames Research center 14-foot wind tunnel (CA23B), volume 1

Separation data were obtained at a Mach number of 0.6 and three incidence angles of 4 deg, 6 deg, and 9 deg. The orbiter angle of attack was varied from 0 to 14 degrees. Longitudinal, lateral and normal separation increments were obtained for fixed 747 angles of attack of 0 deg, 2 deg, and 4 deg while varying orbiter angle of attack. Control surface settings on the 747 carrier included rudder deflections of 0 deg and 10 deg and horizontal stabilizer deflections of -1 deg and +5 deg. Photographs of tested configurations are shown.

Esparza, V.↗

Detailed design package for design of a video system providing optimal visual information for controlling payload and experiment operations with television

A detailed description of a video system for controlling space shuttle payloads and experiments is presented in the preliminary design review and critical design review, first and second engineering design reports respectively, and in the final report submitted jointly with the design package. The material contained in the four subsequent sections of the package contains system descriptions, design data, and specifications for the recommended 2-view system. Section 2 contains diagrams relating to the simulation test configuration of the 2-view system. Section 3 contains descriptions and drawings of the deliverable breadboard equipment. A description of the recommended system is contained in Section 4 with equipment specifications in Section 5.

Source record↗

Wind tunnel investigation of an unpowered helicopter fuselage model with a V-type empennage

The applicability of a V-type empennage on an unpowered semiscale helicopter fuselage is considered as design criteria for improved directional control devices. Configuration changes included variations of V-tail dihedral angle, planform area, and incidence angle. Of the configurations tested, a V-tail with a dihedral angle of 55 deg, a total planform area of 0.244 sq cm, and an incidence angle of 5 deg most nearly match the trim and static stability of the baseline conventional empennage.

Freeman, C. E.↗