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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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At least 289 records · Page 16
All sourcesNASA NTRSDOE OSTI
NASA NTRS1948

Preliminary Investigation to Determine Propeller Section Characteristics by Measuring the Pressure Distribution on an NACA 10-(3)(08)-03 Propeller Under Operating Conditions

An investigation has been made in the Langley 16-foot high-speed tunnel to determine the propeller-section characteristics by measuring the pressure distribution on the airfoil sections of a rotating propeller. The pressures were measured at nine radial stations on an NACA 10-(3)(08)-03 design two-blade propeller. This paper presents the results of the pressure measurements in the form of normal-force and moment coefficients and covers a range of nominal angle of attack (simple blade element theory) from 0 degrees to 4 degrees for a section Mach number range of approximately 0.6 to 1.15 for the outboard stations and approximately 0.3 to 0.6 for inboard stations.

Evans, Albert J↗
NASA NTRS1975

Pressure Distribution at Subsonic Speeds over the Forepart of Two Blunt Circular Cylinders

A wind tunnel investigation was made at subsonic speeds to determine the pressure distribution over the forward part of a circular cylinder. The cylinder was equipped with interchangeable faces, one having a flat face and one having a dome shaped face. The investigation was made over angle of attack range from -1 deg to 26 deg and a Mach number range from 0.30 to 0.89. Pressure coefficients are presented in tabular form and plotted data are presented for some selected angles of attack about the surface of the cylinder.

Lockwood, V. E.↗
NASA NTRS1989

Surface pressure distributions on a delta wing undergoing large amplitude pitching oscillations

Wind tunnel experiments were performed on a 70 deg sweep delta wing to determine the effect of a sinusoidal pitching motion on the pressure field on the suction side of the wing. Twelve pressure taps were placed from 35 to 90 percent of the chord, at 60 percent of the local semi-span. Pressure coefficients were measured as a function of Reynolds number and pitch rate. The pressure coefficient was seen to vary at approximately the same frequency as the pitching frequency. The relative pressure variation at each chord location was comparable for each case. The average pressure distribution through each periodic motion was near the static distribution for the average angle of attack. Upon comparing the upstroke and downstroke pressures for a specific angle of attack, the downstroke pressures were slightly larger. Vortex breakdown was seen to have the most significant effect at the 40 to 45 percent chord location, where a decrease in pressure was apparent.

Thompson, Scott A.↗
NASA NTRS1932

The pressure distribution over a standard and a modified Navy elliptical wing tip on a biplane in flight

This note presents the results of flight pressure distribution tests on the right upper wing panel of a Douglas M-3 airplane equipped in turn with a standard Navy elliptical tip and a tip having the same plan form but modified in its front elevation from the swept-up aspect of the standard tip to a symmetrical aspect. The results are given in such form that the load distribution for any normal-force coefficient within the usual range encountered in flight may easily be determined. The results indicate that the modification in front elevation of the tip had no appreciable effect on the load distribution.

Rhode, Richard V↗
NASA NTRS1935

Wing Pressure Distribution and Rotor-Blade Motion of an Autogiro as Determined in Flight

This report presents the results of tests in which the pressure distribution over the fixed wing of an autogiro was determined in both steady and accelerated flight. In the steady-flight condition, the rotor-blade motion was also measured. These data show that in steady flight the rotor speed as a function of the air speed is largely affected by the variation of the division of load between the rotor and the wing; as the load on the wing increases, the rotor speed decreases. In steady flight the presence of the slipstream increased both the wing lift at a given air speed and the maximum lift coefficient of the wing above the corresponding values without the slipstream. In abrupt high-speed turns, the wing attained a normal force coefficient of unity at almost the initial value of the air speed and experienced its maximum load before maximum acceleration occurred.

Wheatley, John B↗
NASA NTRS1987

Measured pressure distributions inside nonaxisymmetric nozzles with partially deployed thrust reversers

An investigation was conducted in the Langley 16-Foot Transonic Tunnel at static conditions to measure the pressure distributions inside a nonaxisymmetric nozzle with simultaneous partial thrust reversing (50-percent deployment) and thrust vectoring of the primary (forward-thrust) nozzle flow. Geometric forward-thrust-vector angles of 0 and 15 deg. were tested. Test data were obtained at static conditions while nozzle pressure ratio was varied from 2.0 to 4.0. Results indicate that, unlike the 0 deg. vector angle nozzle, a complicated, asymmetric exhaust flow pattern exists in the primary-flow exhaust duct of the 15 deg. vectored nozzle.

Green, Robert S.↗
NASA NTRS1947

Force and Pressure-Distribution Measurements on a Rectangular Wing with Double-Hinged Nose

The previous measurements on airfoils with hinged nose disclosed a comparatively large low-pressure peak at the bend of the hinged nose; which favored the separation of flow. It was therefore attempted to reduce these low-pressure peaks by reducing the camber of the forward profile and thereby ensure a longer adherence of the flow and a maximum lift increase. The forces were measured on a rectangular wing with double-hinged nose and end plates, the pressure distributions were measured in the center section of the wing. The measurements disclosed that the highest lift attained with a single-hinged nose cannot be increased by a double-hinged nose. The sum of the deflection angles of both hinged noses related to the maximum lift is about equal to the corresponding angle of the single-hinge nose (approx. 30 deg to 40). The respective angle of attack in both cases amounts to approx. 21 deg. Even the low-pressure peak is about the same in both cases (P/q approx. -5.5). Therefore, a milder curvature of the forward portion of the profile affords no definite increase of the maximum lift.

Lemme, H. A.↗
NASA NTRS1976

Influence of surface roughness and waviness on film thickness and pressure distribution in elastohydrodynamic contacts

The Christensen theory of a stochastic model for hydrodynamic lubrication of rough surfaces was extended to elastohydrodynamic lubrication between two rollers. Solutions for the reduced pressure at the entrance as a function of the ratio of the average nominal film thickness to the rms surface roughness, were obtained numerically. Results were obtained for purely transverse as well as purely longitudinal surface roughness for cases with or without slip. The reduced pressure was shown to decrease slightly by considering longitudinal surface roughness. The same approach was used to study the effect of surface roughness on lubrication between rigid rollers and lubrication of an infinitely wide slider bearing. Using the flow balance concept, the perturbed Reynolds equation, was derived and solved for the perturbed pressure distribution. In addition, Cheng's numerical scheme was modified to incorporate a single two-dimensional elastic asperity on the stationary surface. The perturbed pressures obtained by these three different models were compared.

Chow, L. S. H.↗
NASA NTRS1973

Effect of sweep angle on the pressure distributions and effectiveness of the ogee tip in diffusing a line vortex

Low-speed wind tunnel tests were conducted to study the influence of sweep angle on the pressure distributions of an ogee-tip configuration with relation to the effectiveness of the ogee tip in diffusing a line vortex. In addition to the pressure data, performance and flow-visualization data were obtained in the wind tunnel tests to evaluate the application of the ogee tip to aircraft configurations. The effect of sweep angle on the performance characteristics of a conventional-tip model, having equivalent planform area, was also investigated for comparison with the ogee-tip configuration. Results of the investigation generally indicate that sweep angle has little effect on the characteristics of the ogee in diffusing a line vortex.

Balcerak, J. C.↗
NASA NTRS1929

Pressure Distribution on a Slotted R.A.F. 31 Airfoil in the Variable Density Wind Tunnel

Measurements were made in the variable density wind tunnel to determine the pressure distribution over one section of a R.A.F. 31 airfoil with a leading edge slot fully open. To provide data for the study of scale effect on this type of airfoil, the tests were conducted with air densities of approximately one and twenty atmospheres.

Jacobs, Eastman N↗