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open access

On the Development of Turbulent Wakes From Vortex Streets

Description: "Wake development behind circular cylinders at Reynolds numbers from 40 to 10,000 was investigated in a low-speed wind tunnel. Standard hot-wire techniques were used to study the velocity fluctuations. The Reynolds number range of periodic vortex shedding is divided into two distinct subranges" (p. 1).
Date: May 29, 1952
Creator: Roshko, Anatol
open access

Preliminary Results of an Investigation of the Effects of Spinner Shape on the Characteristics of an NACA D-Type Cowl Behind a Three-Blade Propeller, Including the Characteristics of the Propeller at Negative Thrust

Description: Memorandum presenting an investigation conducted to determine the effects of spinner shape on the pressure-recovery characteristics of an NACA 1-series D-type cowl operating behind a three-blade single-rotation propeller. Two spinner shapes were considered, an NACA 1-series spinner and a modified spinner, more nearly conical than the 1 series.
Date: November 12, 1953
Creator: Reynolds, Robert M.
open access

Theoretical and experimental investigation of mufflers with comments on engine-exhaust muffler design

Description: Equations are presented for the attenuation characteristics of single-chamber and multiple-chamber mufflers of both the expansion-chamber and resonator types, for tuned side-branch tubes, and for the combination of an expansion chamber with a resonator. Experimental curves of attenuation plotted against frequency are presented for 77 different mufflers with a reflection-free tailpipe termination. The experiments were made at room temperature without flow; the sound source was a loud-speaker. A … more
Date: October 6, 1952
Creator: Davis, Don D., Jr.; Stokes, George M.; Moore, Dewey & Stevens, George L., Jr.
open access

A Study of Hypersonic Small-Disturbance Theory

Description: "A systematic study is made of the approximate inviscid theory of thin bodies moving at such high supersonic speeds that nonlinearity is an essential feature of the equations of flow. The first-order small-disturbance equations are derived for three-dimensional motions involving shock waves, and estimates are obtained for the order of error involved in the approximation. The hypersonic similarity rule of Tsien and Hayes, and Hayes' unsteady analogy appear in the course of the development" (p. 1… more
Date: 1954
Creator: Van Dyke, Milton D.
open access

A Special Investigation to Develop a General Method for Three-Dimensional Photoelastic Stress Analysis

Description: The method of strain measurement after annealing is reviewed and found to be satisfactory for the materials available in this country. A new general method is described for the photoelastic determination of the principal stresses at any point of a general body subjected to arbitrary load. The method has been applied to a sphere subjected to diametrical compressive loads. The results show possibilities of high accuracy.
Date: 1953
Creator: Frocht, M. M. & Guernsey, R., Jr.
open access

Investigation of the Normal Force Accompanying Thrust-Axis Inclination of the NACA 1.167-(0)(03)-058 and the NACA 1.167-(0)(05)-058 Three-Blade Propellers at Forward Mach Numbers to 0.90

Description: Report presenting an investigation to determine the normal force of two three-blade NACA propellers and the agreement of the measured normal force with a theoretical method. Propeller thrust and normal force were measured for a variety of blade angles, angles of attack, and Mach numbers. Results regarding variation with thrust, effect of inclination, and a comparison with theory are provided.
Date: June 23, 1954
Creator: Demele, Fred A. & Otey, William R.
open access

On Transonic Flow Past a Wave-Shaped Wall

Description: "This report is an extension of a previous investigation (described in NACA rep. 1069) concerned with the solution of the nonlinear differential equation for transonic flow past a wavy wall. In the present work several new notions are introduced which permit the solution of the recursion formulas arising from the method of integration in series. In addition, a novel numerical tests of convergence, applied to the power series (in transonic similarity parameter) representing the local Mach number… more
Date: 1953
Creator: Kaplan, Carl
open access

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… more
Date: 1953
Creator: Runyan, Harry L. & Watkins, Charles E.
open access

Investigation of the Effect of Indentation on an M-Plan-Form-Wing--Body Combination at Transonic Speeds

Description: Report presenting an investigation of the effect of body indentation on the aerodynamic characteristics of an M-plan-form-wing-body combination for a variety of angles of attack and Mach numbers. The wing was tested on a plain body and a body with an indentation that was 65 percent of that required for a Mach number of 1.0. Results regarding drag characteristics, lift characteristics, pitching-moment characteristics, and estimated results are provided.
Date: August 4, 1954
Creator: Loving, Donald L.
open access

The effects on dynamic lateral stability and control of large artificial variations in the rotary stability derivatives

Description: This report presents the results of an investigation conducted in the Langley free-flight tunnel to determine the effects of large artificial variations of several rotary lateral-stability derivatives on the dynamic lateral stability and control characteristics of a 45 degree sweptback-wing airplane model. Calculations of the period and damping of the lateral motions and of the response to roll and yaw disturbances were made for correlation with the experimental results. The calculated results … more
Date: June 20, 1952
Creator: Schade, Robert O. & Hassell, James L., Jr.
open access

Theory and Procedure for Determining Loads and Motions in Chine-Immersed Hydrodynamic Impacts of Prismatic Bodies

Description: "A theoretical method is derived for the determination of the motions and loads during chine-immersed water landings of prismatic bodies. This method makes use of a variation of two-dimensional deflected water mass over the complete range of immersion, modified by a correction for three-dimensional flow. Equations are simplified through omission of the term proportional to the acceleration of the deflected mass for use in calculation of loads on hulls having moderate and heavy beam loading" (p.… more
Date: June 25, 1952
Creator: Schnitzer, Emanuel
open access

Analysis of Landing-Gear Behavior

Description: From Summary: "This report presents a theoretical study of the behavior of the conventional type of oleo-pneumatic landing gear during the process of landing impact. The basic analysis is presented in a general form and treats the motions of the landing gear prior to and subsequent to the beginning of shock-strut deflection."
Date: 1953~
Creator: Milwitzky, Benjamin & Cook, Francis E.
open access

A comparison of the experimental subsonic pressure distributions about several bodies of revolution with pressure distributions computed by means of the linearized theory

Description: "An analysis is made of the effects of compressibility on the pressure coefficients about several bodies of revolution by comparing experimentally determined pressure coefficients with corresponding pressure coefficients calculated by the use of the linearized equations of compressible flow. The results show that the theoretical methods predict the subsonic pressure-coefficient changes over the central part of the body but do not predict the pressure-coefficient changes near the nose. Extrapola… more
Date: November 5, 1951
Creator: Matthews, Clarence W.
open access

Pumping and thrust characteristics of several divergent cooling-air ejectors and comparison of performance with conical and cylindrical ejectors

Description: Report presenting an investigation of the performance of four divergent ejector configurations with shroud-exit to primary-nozzle-exit diameter ratios of 1.2 and 1.3 with minimum-shroud to primary-nozzle-exit diameter ratios of 1.1 and 1.2. A comparison of the performance of conical, cylindrical, and divergent ejectors showed that on the basis of similar design variables each configuration has merit. Results regarding the divergent-ejector performance and comparison of ejectors are provided.
Date: January 20, 1954
Creator: Huntley, S. C. & Yanowitz, Herbert
open access

Experiments to Determine Neighborhood Reactions to Light Airplanes With and Without External Noise Reduction

Description: "The work reported was part of a program of experimentation with external noise reduction on light airplanes. This particular study was in effect a byproduct survey conceived to utilize already available equipment and personnel to further the findings of the original research and to determine reactions in populated neighborhoods to light aircraft with and without noise-reduction equipment. The findings indicate that at the 10 sites within and about metropolitan Boston the degree of noise reduct… more
Date: May 5, 1950
Creator: Elwell, Fred S.
open access

Performance of a supersonic rotor having high mass flow

Description: Report presenting testing of a 14-inch supersonic mixed-flow rotor with a supersonic leading edge and an inlet radius ratio of 0.52, which was designed for impulse operation and uniform work output and tested in Freon-12. Results regarding overall rotor performance, entrance flow, distribution of static pressure on the casing, and exit flow are provided.
Date: July 19, 1954
Creator: Schacht, Ralph L.; Goldstein, Arthur W. & Neumann, Harvey E.
open access

The Use of a Leading-Edge Area-Suction Flap to Delay Separation of Air Flow From the Leading Edge of a 35 Degrees Sweptback Wing

Description: "An investigation was conducted on a 35 degree swept-wing model to determine the aerodynamic characteristics and suction requirements of a model having a leading-edge area-suction flap deflected 40 degrees" (p. 1). The procedures, corrections needed, force characteristics, suction requirements, and pressure distributions are described.
Date: December 10, 1953
Creator: Holzhauser, Curt A. & Martin, Robert K.
open access

Analytical Derivation and Experimental Evaluation of Short-Bearing Approximation for Full Journal Bearing

Description: From Introduction: "This report extends the short-bearing pressure-distribution function of Michell and Cardullo to give equations for the various bearing characteristics. This short-bearing approximation makes available formulas relating eccentricity ratio to applied load, attitude angle, angular position of peak film pressure to unit pressure on projected area."
Date: June 12, 1953
Creator: DuBois, George B. & Ocvirk, Fred W.
open access

Wind-Tunnel Experiments Concerning the Dynamic Behavior of a Low-Speed Slowly Spinning Fin-Stabilized Rocket

Description: Report presenting an investigation made in the stability tunnel to determine the effectiveness with which the dynamic characteristics of a low-speed slowly spinning fin-stabilized rocket could be studied by a free-oscillation technique and to study certain peculiarities of behavior. Results regarding the stability of the original model, effect of reversing direction of the arming propeller, effect of increasing size of reversed-rotation of the arming propeller, effect of removing the arming pro… more
Date: July 6, 1954
Creator: Bird, John D. & Lichtenstein, Jacob H.
open access

Prediction of flame velocities of hydrocarbon flames

Description: The laminar-flame-velocity data previously reported by the Lewis Laboratory are surveyed with respect to the correspondence between experimental flame velocities and values predicted by semitheoretical and empirical methods. The combustible mixture variables covered are hydrocarbon structure (56 hydrocarbons), equivalence ratio of fuel-air mixture, mole fraction of oxygen in the primary oxygen-nitrogen mixture (0.17 to 0.50), and initial mixture temperature (200 degrees to 615 degrees k). The s… more
Date: January 2, 1953
Creator: Dugger, Gordon L. & Simon, Dorothy M.
open access

The Use of Area Suction to Increase the Effectiveness of a Trailing-Edge Flap on a Triangular Wing of Aspect Ratio 2

Description: "A wind-tunnel investigation was conducted to determine the effect of applying area-suction boundary-layer control to a constant-chord plain flap on a triangular wing of aspect ratio 2. The results showed that with small amounts of suction applied near the leading edge of the flap, high lift at relatively low attitudes can be obtained" (p. 1). The typical lift, drag, pitching-moment data, effects of the porous area, effects of suction, and comparison of theoretical and experimental flap lift ar… more
Date: April 1, 1954
Creator: Kelly, Mark W. & Tolhurst, William H., Jr.
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