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Some Recent Contributions to the Study of Transition and Turbulent Boundary Layers
Report presenting a paper in two parts about transition and turbulent boundary layers. The first part reviews the current problem of the instability of laminar boundary layers. The second part reviews the current state of knowledge of the mechanics of turbulent boundary layers and of the methods now being used for fundamental studies of the turbulent fluctuations in turbulent boundary layers.
Date:
April 1947
Creator:
Dryden, Hugh L.
System:
The UNT Digital Library
Considerations of the Total Drag of Supersonic Airfoil Sections
The results of calculations of the viscous and pressure drags of some two-dimensional supersonic airfoils at zero lift are presented. The results indicate that inclusion of viscous drag alters many previous results regarding the desirability of certain airfoil shapes for securing low drags at supersonic speeds. At certain Reynolds and Mach numbers, for instance, a circular-arc airfoil may theoretically have less drag than the previously advocated symmetrical wedge-shape profile; although under different conditions, the circular-arc airfoil may have a higher drag.
Date:
July 1947
Creator:
Ivey, H. Reese & Klunker, E. Bernard
System:
The UNT Digital Library
Aerodynamic Investigation of a Cup Anemometer
Results of an investigation wherein the change of the normal force coefficient with Reynolds Number was obtained statically for a 15.5-centimeter hemispherical cup.
Date:
July 1934
Creator:
Hubbard, John D. & Brescoll, George P.
System:
The UNT Digital Library
Bending Tests of Metal Monocoque Fuselage Construction
Study of the bending stress in smooth skin, aluminum alloy, true monocoque fuselage sections of varying ratio of diameter to thickness.
Date:
November 1930
Creator:
Mossman, Ralph W. & Robinson, Russell G.
System:
The UNT Digital Library
Two-Dimensional Irrotational Transonic Flows of a Compressible Fluid
The methods of NACA TN No. 995 have been slightly modified and extended in include flows with circulation by considering the alteration of the singularities of the incompressible solution due to the presence of the hypergeometric functions in the analytic continuation of the solution. It was found that for finite Mach numbers the only case in which the nature of the singularity can remain unchanged is for a ratio of specific heats equal to -1. From a study of two particular flows it seems that the effect of geometry cannot be neglected, and the conventional "pressure-correction" formulas are not valid, even in the subsonic region if the body is thick, especially if there is a supersonic region in the flow.
Date:
June 1948
Creator:
Kuo, Yung-Huai
System:
The UNT Digital Library
Tables and charts of flow parameters across oblique shocks
Shock-wave equations have been evaluated for a range of Mach number in front of the shock from 1.05 to 4.0. Mach number behind the shock, pressure ratio, derivation of flow, and angle of shock are presented on charts. Values are also included for density ratio and change in entropy.
Date:
August 1948
Creator:
Neice, Mary M.
System:
The UNT Digital Library
Two-dimensional subsonic compressible flows past arbitrary bodies by the variational method
Instead of solving the nonlinear differential equation which governs the compressible flow, an approximate method of solution by means of the variational method is used. The general problem of steady irrotational flow past an arbitrary body is formulated. Two examples were carried out, namely, the flow past a circular cylinder and the flow past a thin curved surface. The variational method yields results of velocity and pressure distributions which compare excellently with those found by existing methods. These results indicate that the variational method will yield good approximate solution for flow past both thick and thin bodies at both high and low Mach numbers.
Date:
March 1951
Creator:
Wang, Chi-Teh
System:
The UNT Digital Library
Tables for the Computation of Wave Drag of Arrow Wings of Arbitrary Airfoil Section
Tables and computing instructions for the rapid evaluation of the wave drag of delta wings and of arrow wings having a ration of the tangent of the trailing-edge sweep angle to the tangent of the leading-edge sweep angle in the range from -1.0 to 0.8. The tables cover a range of both subsonic and supersonic leading edges.
Date:
June 1954
Creator:
Grant, Frederick C. & Cooper, Morton
System:
The UNT Digital Library
Summary of 65-Series Compressor-Blade Low-Speed Cascade Data by Use of the Carpet-Plotting Technique
Carpet plots included permit the selection of the blade camber and the design angle of attack required to fulfill a design vector diagram. Other carpet plots provide means for the prediction of off-design turning angles.
Date:
February 1957
Creator:
Felix, A. Richard
System:
The UNT Digital Library
Charts for the Computation of Equilibrium Composition of Chemical Reactions in the Carbon-Hydrogen-Oxygen-Nitrogen System at Temperatures From 2000° to 5000° Degrees K
Charts are provided for the estimation and progressive adjustment of two independent variables on which the calculations are based. Additional charts are provided for the graphical calculation of the composition.
Date:
July 1948
Creator:
Huff, Vearl N. & Calvert, Clyde S.
System:
The UNT Digital Library
An approximate spin design criterion for monoplanes
"A quantitative criterion of merit has been needed to assist airplane designers to incorporate satisfactory spinning characteristics into new designs. An approximate empirical criterion, based on the projected side area and the mass distribution of the airplane, has been formulated in a recent British report. In the present paper, the British results have been analyzed and applied to American designs. A simpler design criterion based solely on the type and the dimensions of the tail, has been developed: it is useful in a rapid estimation of whether a new design is likely to comply with the minimum requirements for safety in spinning" (p. 1).
Date:
June 1939
Creator:
Seidman, Oscar & Donlan, Charles J.
System:
The UNT Digital Library
Reciprocity relations in aerodynamics
From Introduction: "The purpose of the present paper is twofold. First, a close connection will be established between reverse-flow theorems in subsonic and supersonic, steady-state wing theory and known reciprocity relations between two solutions of the equation the flow field."
Date:
May 1952
Creator:
Heaslet, Max A. & Spreiter, John R.
System:
The UNT Digital Library
The Unsteady Lift of a Finite Wing
Note discussing the lift of a finite wing including the calculations and constants for each step of the lift. This information is compared against the lift of an infinite wing. From Summary: "Unsteady lift function for wings of finite aspect ratio have been calculated by approximate methods involving corrections of the aerodynamic inertia and of the angle of the infinite wing. The starting lift of the finite wing is found to be only slightly less than that of the infinite wing; whereas the final lift may be considerably less. The calculations indicate that the distribution of lift near the start is similar to the final distribution."
Date:
January 1939
Creator:
Jones, Robert T.
System:
The UNT Digital Library
Further Measurements of Normal Accelerations on Racing Airplanes
This report details the acceleration data collected from racing airplanes during actual races. The data was collected in order to make recommendations regarding the structural safety of racing airplanes and the methods of operating racing airplanes that reduces the probability of subjecting them to extreme air loads. The records do not lead to any conclusions regarding maximum air loads.
Date:
February 1936
Creator:
Kirschbaum, H. W. & Scudder, N. F.
System:
The UNT Digital Library
A Low-Speed Experimental Investigation of the Effect of a Sandpaper Type of Roughness on Boundary-Layer Transition
Report describing the effects of an area of roughness on the velocity and turbulence measurements of an airfoil. It details the effects of the size, location, and height of the roughness on the Reynolds number. From Summary: "An investigation was made in the Langley low-turbulence pressure tunnel to determine the effect of size and location of a sandpaper type of roughness on the Reynolds number for transition."
Date:
1958
Creator:
Horton, Elmer A. & von Doenhoff, Albert E.
System:
The UNT Digital Library
Comparison of Vee-Type and Conventional Tail Surfaces in Combination with Fuselage and Wing in the Variable-Density Tunnel
"The pitching and the yawing moments of a vee-type and a conventional type of tail surface were measured. The tests were made in the presence of a fuselage and a wing-fuselage combination in such a way as to determine the moments contributed by the tail surfaces" (p. 1).
Date:
July 1941
Creator:
Greenberg, Harry
System:
The UNT Digital Library
The Calculation of Span Load Distributions of Swept-Back Wings
"Span load distributions of swept-back wings have been calculated. The method used was to replace the wing with a bound vortex at the quarter-chord line and to calculate the downwash due to the system of bound and trailing vortices to conform at the three-quarter-chord line to the slope of the flat-plate wing surface. Results are given for constant-chord and 5:1 tapered plan forms, for sweep-back angles of 0 degrees, 30 degrees, and 45 degrees, and for aspect ratios of 3, 6, and 9" (p. 1).
Date:
December 1941
Creator:
Mutterperl, William
System:
The UNT Digital Library
Methods of Analyzing Wind-Tunnel Data for Dynamic Flight Conditions
"The effects of power on the stability and the control characteristics of an airplane are discussed and methods of analysis are given for evaluating certain dynamic characteristics of the airplane that are not directly discernible from wind-tunnel tests alone. Data are presented to show how the characteristics of a model tested in a wind tunnel are affected by power. The response of an airplane to a rolling and a yawing disturbance is discussed, particularly in regard to changes in wing dihedral and fin area" (p. 1).
Date:
October 1941
Creator:
Donlan, C. J. & Recant, I. G.
System:
The UNT Digital Library
Aerodynamic heating and the deflection of drops by an obstacle in an air stream in relation to aircraft icing
From Summary: "Two topics of interest to persons attempting to apply the heat method of preventing ice formation on aircraft are considered. Surfaces moving through air at high speed are shown, both theoretically and experimentally, to be subject to important aerodynamic heating effects that will materially reduce the heat required to prevent ice. Numerical calculations of the path of water drops in an air stream around a circular cylinder are given. From these calculations, information is obtained on the percentage of the swept area cleared of drops."
Date:
October 1940
Creator:
Kantrowitz, Arthur
System:
The UNT Digital Library
Principal Effects of Axial Load on Moment-Distribution Analysis of Rigid Structures
"This thesis presents the method of moment distribution modified to include the effect of axial load upon the bending moments. This modification makes it possible to analyze accurately complex structures, such as rigid fuselage trusses, that heretofore had to be analyzed by approximate formulas and empirical rules. The method is simple enough to be practicable even for complex structures, and it gives a means of analysis for continuous beams that is simpler than the extended three-moment equation now in common use" (p. 1).
Date:
July 1935
Creator:
James, Benjamin Wylie
System:
The UNT Digital Library
Effects of Some Present-Day Airplane Design Trends on Requirements for Lateral Stability
Note presenting computations made to determine the effects of some airplane design trends on the fin area and the dihedral angle required for lateral stability. The specific factors studied were wing loading, moments of inertia in roll and yaw, wing chord, and tail length. The results of the computations are presented in the form of diagrams of variations of fin area with dihedral angle for neutral stability.
Date:
June 1941
Creator:
Bamber, Millard J.
System:
The UNT Digital Library
Spin Tests of Two Models of a Low-Wing Monoplane to Investigate Scale Effect in the Model Test Range
Note presenting testing performed on scale models of a modern low-wing monoplane in the 15-foot free-spinning wind tunnel. Results are presented in the form of charts that afford a direct comparison between the spins of the two models for a number of different conditions. The results indicate that, within the range of Reynolds numbers used in the present investigation, such factors as difficulty of ballasting and testing are more important in determining proper model size than the changes in scale effect likely to result from the use of different sizes of models.
Date:
May 1941
Creator:
Donlan, Charles J.
System:
The UNT Digital Library
Corrugated Metal Diaphragms for Aircraft Pressure-Measuring Instruments
Note presenting a description of a large number of corrugated diaphragms of beryllium copper, phosphor bronze, and Z-nickel with geometrically similar outlines but various diameters and thicknesses were formed by hydraulic pressing. The apparatus and technique used in the manufacture, testing, and heat treatment are described. Results regarding pressure-deflection curves, load limit, effect of center reinforcing, snap-action diaphragms, deflection traverse, thickness variations, and concentrated central loads are provided.
Date:
November 1939
Creator:
Wildhack, W. A. & Goerke, V. H.
System:
The UNT Digital Library
The Variation in Pressure in the Cabin of an Airplane in Flight
From Summary: "The pressure in the cabin of a Fairchild cabin monoplane was surveyed in flight, and was found to decrease with increased air speed over the fuselage and to vary with the number and location of openings in the cabin. The maximum depression of 2.2 inches of water (equivalent pressure altitude at sea level of 152 feet) occurred at the high speed of the airplane in level flight with the cabin closed."
Date:
March 1931
Creator:
Gough, Melvin N.
System:
The UNT Digital Library