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Boundary-induced upwash for yawed and swept-back wings in closed circular wind tunnels

Description: Report presenting a determination of the tunnel-induced velocities for yawed and swept-back airfoils in a closed circular wind tunnel. Calculations were performed for elemental horseshoe vortices with one tip of the bound vortex on the tunnel axis for a range of yaw angles and bound-vortex lengths.
Date: May 1947
Creator: Eisenstadt, Bertram J.
Partner: UNT Libraries Government Documents Department

Experimental investigation of two-dimensional tunnel-wall interference at high subsonic speeds

Description: Report presenting a determination of the tunnel-wall interference for a two-dimensional-flow, rectangular, closed-throat wind tunnel over a range of Mach numbers. Aerodynamic data obtained showed that the influence of the walls becomes progressively greater with increasing Mach number and increasing chord-height ratio.
Date: December 1953
Creator: Knechtel, Earl D.
Partner: UNT Libraries Government Documents Department

Preliminary investigation of a technique of producing a heated core in a supersonic wind-tunnel stream

Description: Report presenting an investigation at Mach numbers 1.9 and 3.0 to demonstrate that a central core of air of high stagnation temperature can be produced in the test section of a supersonic wind tunnel. This makes performing wind tunnel testing cheaper and controls for more variables. Results regarding the core studies at Mach number 1.9 and 3.0 and diffuser performance at Mach number 1.9 are provided.
Date: February 18, 1955
Creator: Rousso, Morris D. & Beheim, Milton A.
Partner: UNT Libraries Government Documents Department

Considerations on the effect of wind-tunnel walls on oscillating air forces for two-dimensional subsonic compressible flow

Description: This report treats the effect of wind-tunnel walls on the oscillating two-dimensional air forces in a compressible medium. The walls are simulated by the usual method of placing images at appropriate distances above and below the wing. An important result shown is that, for certain conditions of wing frequency, tunnel height, and Mach number, the tunnel and wing may form a resonant system so that the forces on the wing are greatly changed from the condition of no tunnel walls. It is pointed out that similar conditions exist for three-dimensional flow in circular and rectangular tunnels and apparently, within certain Mach number ranges, in tunnels of nonuniform cross section or even in open tunnels or jets.
Date: 1953
Creator: Runyan, Harry L. & Watkins, Charles E.
Partner: UNT Libraries Government Documents Department

The effect of the walls in closed type wind tunnels

Description: "A series of tests has been conducted during the period 1925-1927 by the National Advisory Committee for Aeronautics in the variable-density wind tunnel on several airfoil models of different sizes and sections to determine the effect of tunnel-wall interference and to determine a correction which can be applied to reduce the error caused thereby. The use of several empirical corrections was attempted with little success. The Prandtl theoretical corrections give the best results, and their use is recommended for correcting closed wind tunnel results to the conditions of free air" (p. 375).
Date: 1928
Creator: Higgins, George J.
Partner: UNT Libraries Government Documents Department

The NACA CYH airfoil section

Description: The NACA CYH airfoil section is described and its aerodynamic characteristics are given as tested in the NACA variable density wind tunnel at twenty atmosphere pressure. This section has a low drag, a high maximum lift, and a small travel of center of pressure.
Date: June 1926
Creator: Higgins, George J.
Partner: UNT Libraries Government Documents Department

Wall interference in closed type wind tunnels

Description: "A series of tests has been conducted by the National Advisory Committee for Aeronautics, in the variable density wind tunnel on several airfoils of different sizes and sections to determine the effect of tunnel wall interference and to determine a correction which can be applied to reduce the error caused thereby. The use of several empirical corrections was attempted with little success. The Prandtl theoretical correction gives the best results and its use is recommended for correcting closed wind tunnel results to conditions of free air" (p. 1).
Date: March 1927
Creator: Higgins, George J.
Partner: UNT Libraries Government Documents Department

High-speed wind tunnels

Description: Wind tunnel construction and design is discussed especially in relation to subsonic and supersonic speeds. Reynolds Numbers and the theory of compressible flows are also taken into consideration in designing new tunnels.
Date: November 1936
Creator: Ackeret, J.
Partner: UNT Libraries Government Documents Department

Determination of boundary-layer transition Reynolds numbers by surface-temperature measurements of a 10 degree cone in various NACA supersonic wind tunnels

Description: Report presenting an investigation in several NACA wind tunnels to determine transition Reynolds numbers on a 10 degree cone at zero angle of attack. The trends of transition Reynolds number with stream Reynolds number and Mach number are not consistent across the different tunnels. These inconsistencies are attributed to variations in free-stream turbulence, flow irregularities introduced by compressor systems, and other airstream disturbances like compression- or expansion-wave boundary-layer interactions.
Date: October 1953
Creator: Ross, Albert O.
Partner: UNT Libraries Government Documents Department

Tests of the N.P.L. airship models in the variable density wind tunnel

Description: Report presenting testing in the variable density wind tunnel on two airship models known as the NPL Standardization Models, long and short. The resistance or shape coefficients were determined for each model through a range of Reynolds numbers. Further work is found to be necessary in the standardization of wind tunnels.
Date: September 1927
Creator: Higgins, George J.
Partner: UNT Libraries Government Documents Department

Jet-boundary corrections for reflection-plane models in rectangular wind tunnels

Description: A detailed method for determining the jet-boundary corrections for reflection-plane models in rectangular wind tunnels is presented. The method includes the determination of the tunnel span local distribution and the derivation of equations for the corrections to the angle of attack, the lift and drag coefficients, and the pitching-, rolling-, yawing-, and hinge-moment coefficients. The principle effects of aerodynamic induction and of the boundary-induced curvature of the streamlines have been considered. An example is included to illustrate the method. Numerical values of the more important corrections for reflection-plane models in 7 by 10-foot closed wind tunnels are presented.
Date: April 13, 1943
Creator: Swanson, Robert S. & Toll, Thomas A.
Partner: UNT Libraries Government Documents Department

The development and performance of two small tunnels capable of intermittent operation at Mach numbers between 0.4 and 4.0

Description: Report presenting the design, development, and performance of equipment suitable for use by educational institutions for student training and basic compressible-flow research. Supersonic nozzles designed for a range of Mach numbers were tested in the blowdown tunnel and produced average Mach numbers close to the design values.
Date: September 1950
Creator: Lindsey, Walter F. & Chew, William L.
Partner: UNT Libraries Government Documents Department

Wind Tunnel Study of the Influence of Orifice Geometry and Flow Rates on the Measured Pressure Error of a Static Pressure Probe at Mach 3

Description: Abstract: Tests were conducted in the Jet Propulsion Laboratory's 20-inch Supersonic Wind Tunnel to determine the effect of hole-spacing geometry on the measured pressure error due to "breathing" for a pressure-sensing probe at Mach 3.01.
Date: November 1960
Creator: Zumwalt, G. W.
Partner: UNT Libraries Government Documents Department

An NACA transonic test section with tapered slots tested at Mach numbers to 1.26

Description: Report presenting testing of an NACA octagonal transonic slotted test section has been modified to include slots with point origins located at the tunnel aerodynamic minimum and which diverged linearly over a length of 1.5 jet diameters. Pressure distributions along the axis and one wall of the slotted configuration are presented and indicate the attainment of a test region with satisfactory uniform Mach number distributions.
Date: March 30, 1950
Creator: Ward, Vernon G.; Whitcomb, Charles F. & Pearson, Merwin D.
Partner: UNT Libraries Government Documents Department

The Langley annular transonic tunnel

Description: Report describes the development of the Langley annular transonic tunnel, a facility in which test Mach numbers from 0.6 to slightly over 1.0 are achieved by rotating the test model in an annular passage between two concentric cylinders. Data obtained for two-dimensional airfoil models in the Langley annular transonic tunnel at subsonic and sonic speeds are shown to be in reasonable agreement with experimental data from other sources and with theory when comparisons are made for nonlifting conditions or for equal normal-force coefficients rather than for equal angles of attack. The trends of pressure distributions obtained from measurements in the Langley annular transonic tunnel are consistent with distributions calculated for Prandtl-Meyer flow.
Date: January 19, 1953
Creator: Habel, Louis W.; Henderson, James H. & Miller, Mason F.
Partner: UNT Libraries Government Documents Department

Preliminary investigation of constant-geometry, variable Mach number, supersonic tunnel with porous walls

Description: Report presenting a method of generating variable Mach number supersonic flow in a channel of fixed geometry by the removal of air through uniform porous walls. Calculated porosity distributions are presented for several minimum-length nozzles designed to operate at Mach numbers up to 2.0. Experimental and analytical data is presented.
Date: May 3, 1950
Creator: Nelson, William J. & Klevatt, Paul L.
Partner: UNT Libraries Government Documents Department

The Langley two-dimensional low-turbulence pressure tunnel

Description: From Summary: "A description is presented of the Langley two-dimensional low-turbulence pressure tunnel and a history is given of the work done at the Langley Memorial Aeronautical Laboratory which led to the achievement of a remarkably low level of turbulence in the air stream of this wind tunnel. The types of investigations to which the tunnel is suited and the methods of obtaining and correcting data are also discussed."
Date: May 1947
Creator: von Doenhoff, Albert E. & Abbott, Frank T.
Partner: UNT Libraries Government Documents Department

Experimental investigation of the effectiveness of various suction-slot arrangements as a means for increasing the maximum lift of the NACA 65(sub 3)-018 airfoil section

Description: Report presenting a wind-tunnel investigation to explore the possibility of employing boundary-layer suction slots as a means for delaying laminar separation at the leading edge and turbulent separation over the rear portions of the airfoil section at high lift coefficients. Results regarding lift and drag are explored.
Date: March 31, 1950
Creator: Racisz, Stanley F.
Partner: UNT Libraries Government Documents Department

Studies of the use of Freon-12 as a wind tunnel testing medium

Description: Report presenting a comparison of studies relating to the use of Freon-12 as a substitute medium for air in aerodynamic testing and methods for predicting the aerodynamic characteristics of bodies in air. The Freon charging and recovery system for the Langley low-turbulence pressure tunnel is described.
Date: August 1953
Creator: von Doenhoff, Albert E.; Braslow, Albert L. & Schwartzberg, Milton A.
Partner: UNT Libraries Government Documents Department

Slotted-boundary interference effects on wedge airfoils at low supersonic Mach numbers

Description: Report presenting an experimental investigation of pressure disturbances caused by the reflection of two-dimensional shock waves from a slotted boundary at Mach numbers between 1.0 and 1.5. Simple-wedge airfoils with three different apex angles were used to generate shock waves and the static pressures ere measured at various points along the surface of each airfoil.
Date: July 30, 1953
Creator: Nelson, William J. & Vick, Allen R.
Partner: UNT Libraries Government Documents Department

Initial flutter tests in the Langley transonic blowdown tunnel and comparison with free-flight flutter results

Description: Report presenting an experimental wing-flutter investigation in the transonic blowdown tunnel, which is equipped with a slotted test section, in order to determine the correlation between transonic-wind-tunnel and free-fall flight flutter results. Very good agreement was observed between wind tunnel and flight flutter test results, which showed the feasibility of conducting flutter tests in transonic wind tunnels with slotted test sections.
Date: January 7, 1953
Creator: Bursnall, William J.
Partner: UNT Libraries Government Documents Department