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Rotationally Symmetric Potential Flows

Description: This paper includes the following topics: 1) Characteristic differential equations; 2) Treatment of practical examples; 3) First example: Diffuser; and 4) Second Example: Nozzle.
Date: November 1949
Creator: Schäefer, Manfred & Tollmien, W.
Partner: UNT Libraries Government Documents Department

Acoustics of a nonhomogeneous moving medium.

Description: Report discussing theoretical basis of the acoustics of a moving nonhomogeneous medium. Experiments that illustrate or confirm some of the theoretical explanation or derivation of these acoustics are also included.
Date: February 1956
Creator: Blokhintsev, D I
Partner: UNT Libraries Government Documents Department

Some Diophantine Equations

Description: This paper will be devoted to an examination of several general and specific equations and systems of equations of the diophantine type. Only algebraic equations with integral coefficients, not all zero, will considered. The elementary properties of the integers will be assumed.
Date: January 1960
Creator: Pressly, Kirby Smith
Partner: UNT Libraries

General method for exponential-type equations for eight- and nine-point prismatic arrays

Description: The results of three-parameter experiments are commonly interpreted by the trilinear equation for eight data in a prismatic array. Ifa center point estimate is available, the eight-and nine-point arrays can be represented by new exponential-type equations. The equations are easy to generate, they are invariant under data translation, and they estimate curvature coefficients.
Date: January 1, 2009
Creator: Silver, Gary L
Partner: UNT Libraries Government Documents Department

Generalized Monge-Kantorovich optimization for grid generation and adaptation in LP

Description: The Monge-Kantorovich grid generation and adaptation scheme of is generalized from a variational principle based on L{sub 2} to a variational principle based on L{sub p}. A generalized Monge-Ampere (MA) equation is derived and its properties are discussed. Results for p > 1 are obtained and compared in terms of the quality of the resulting grid. We conclude that for the grid generation application, the formulation based on L{sub p} for p close to unity leads to serious problems associated with the boundary. Results for 1.5 {approx}< p {approx}< 2.5 are quite good, but there is a fairly narrow range around p = 2 where the results are close to optimal with respect to grid distortion. Furthermore, the Newton-Krylov methods used to solve the generalized MA equation perform best for p = 2.
Date: January 1, 2009
Creator: Delzanno, G L & Finn, J M
Partner: UNT Libraries Government Documents Department

An Elementary Review of the Mathieu-Hill Equation of Real Variable Based on Numerical Solutions

Description: Abstract: description is given of a large number of trajectories of Mathieu's equation made on the ENIAC in 1948 and available at BRL. A large chart describing the behaviour of the solutions is given. The occasion is taken to review the essentials of the Mathieu theory for the benefit of the occasional user-proceeding from the point of view of an inspection of the numerical data.
Date: April 1955
Creator: Zaroodny, Serge J.
Partner: UNT Libraries Government Documents Department

Two-Dimensional Potential Flows

Description: Contents include the following: Characteristic differential equations - initial and boundary conditions. Integration of the second characteristic differential equations. Direct application of Meyer's characteristic hodograph table for construction of two-dimensional potential flows. Prandtl-Busemann method. Development of the pressure variation for small deflection angles. Numerical table: relation between deflection, pressure, velocity, mach number and mach angle for isentropic changes of state according to Prandtl-Meyer for air (k = 1.405). References.
Date: November 1949
Creator: Schäefer, Manfred & Tollmien, W.
Partner: UNT Libraries Government Documents Department

Theory of Characteristics

Description: The theory of characteristics will be presented generally for quasilinear differential equations of the second order in two variables. This is necessary because of the manifold requirements to be demanded from the theory of characteristics.
Date: September 1949
Creator: Tollmien, W.
Partner: UNT Libraries Government Documents Department

A method for estimating variations in the roots of the lateral-stability quartic due to changes in mass and aerodynamic parameters of an airplane

Description: Report presenting a method for estimating variations in the roots of the lateral-stability quartic due to changes in mass and aerodynamic parameters of an airplane. The method is applied to three high-speed airplanes and the changes in their lateral stability characteristics are determined by considering increments in various airplane parameters.
Date: January 1954
Creator: Gates, Ordway B., Jr. & Woodling, C. H.
Partner: UNT Libraries Government Documents Department

A method of computing subsonic flows around given airfoils

Description: From Summary: "An extremely simple computational method is established for obtaining circulatory flows around given bodies to a high degree of accuracy for flows satisfying the linear pressure and specific-volume equation of state. The method depends not on an integral equation but on the transformation from the holograph to the physical plane involving the determination of an arbitrary analytic function. The determination of the arbitrary analytic function by elementary means results in a close approximation of the given body."
Date: March 1950
Creator: Gelbart, Abe & Resch, Daniel
Partner: UNT Libraries Government Documents Department

Procedure for calculating flutter at high supersonic speed including camber deflections, and comparison with experimental results

Description: Report presenting a method that can be used at high supersonic Mach numbers for calculating the flutter speed of wings with camber in their deflection modes. It is used to calculate the flutter speed of some wings that had been tested at Mach numbers of 1.3 and 3.0. Theoretical comparisons of the tested wings are also provided.
Date: September 1958
Creator: Morgan, Homer G.; Huckel, Vera & Runyan, Harry L.
Partner: UNT Libraries Government Documents Department

Expected numbers of maxima and minima of a stationary random process with non-Gaussian frequency distribution

Description: Report presenting a method for calculating the expected number of maxima or minima of a random process with non-Gaussian frequency distribution from the statistical moments of the process and its first two derivatives. The effects of skewness and kurtosis can also be calculated provided the required moments are known.
Date: April 1957
Creator: Diederich, Franklin W.
Partner: UNT Libraries Government Documents Department

Estimation of lift and drag of airfoils at near sonic speeds and in the presence of detached shock waves

Description: Report presenting a semiempirical method of estimating the forces on airfoil at near sonic speeds and in the presence of detached shock waves. The calculated values were found to be in good agreement with wind-tunnel testing of the forces on sharp-nose airfoils and two-dimensional wings.
Date: February 23, 1949
Creator: Mayer, John P.
Partner: UNT Libraries Government Documents Department

A simplified method for the determination and analysis of the neutral-lateral-oscillatory-stability boundary

Description: A necessary condition for neutral oscillatory stability is that Routh's discriminant r, formed from the coefficients of the stability equation, is equal to zero. Computations obtained from rsub1=0 and d=0 show very good agreement with the results calculated by the expression for r=0. The nature of the modes of motion as a function of the directional-stability derivative and the effective-dihedral derivative is discussed in detail.
Date: 1949
Creator: Sternfield, Leonard & Gates, Ordway B., Jr.
Partner: UNT Libraries Government Documents Department

Energy Dissipation by Fast Electrons

Description: Report discussing the energy dissipated by fast electrons at different distances from monoenergetic electron sources, for plane perpendicular and point isotropic sources including tabulations and a summary of the theoretical methods and data utilized, and a table of spatial moments.
Date: September 10, 1959
Creator: Spencer, L. V.
Partner: UNT Libraries Government Documents Department

Influence of a Sector Ground Screen on the Field of a Vertical Antenna

Description: Report show the field of a short vertical antenna on a homogeneous ground is modified by the presence of a metallic screen. The screen is taken in the form of a circular disk and a concentric sector. The modification of the field is expressed in the form of surface integrals over the disk and the sector. Extensive numerical results for these basic integrals are given and a number of applications are illustrated.
Date: April 15, 1963
Creator: Wait, James R. & Walters, Lillie C.
Partner: UNT Libraries Government Documents Department

Refractive Indices and Densities of Aqueous Solutions of Invert Sugar

Description: Report of the refractive indices and densities of aqueous solutions of invert sugar at temperatures of 15, 20, 25, and 30º C, for concentrations up to about 82 percent of invert sugar (by weight). From the results, equations have been derived which relate the refractive index and percent of invert sugar (weight in air) at each temperature. Other equations relate the absolute density and percent of invert sugar (weight in vacuum) at each temperature. Five-decimal tables giving the refractive indices and densities of invert sugar solutions containing 1 to 85 percent of sugar are given for each percentage of invert sugar at the four temperatures.
Date: June 7, 1963
Creator: Snyder, Carl F. & Hattenburg, Albert T.
Partner: UNT Libraries Government Documents Department

Thermal Expansion of Technical Solids at Low Temperatures: A Compilation From the Literature

Description: Report giving tables of the linear contraction relative to 293 ºK, (L293ºLT)/L293, and the linear expansion coefficient, dL/L293dT, of thirty elements, forty-five alloys, twenty-two other inorganic substances and twenty plastics and elastomers in the temperature range, 0 to 300 ºK.
Date: May 19, 1961
Creator: Corruccini, Robert J. & Gniewek, John J.
Partner: UNT Libraries Government Documents Department

Microwave Impedance Measurements and Standards

Description: Report presenting a survey and discussion of well-known microwave impedance measurement techniques. The discussion includes an introduction which emphasizes basic concepts and reflection coefficient-voltage standing-wave ratio relationships. Sources of error in the various measurement techniques are discussed and methods to reduce errors are presented. Methods using rotating loops and resonance lines are included and a brief discussion of microwave impedance standards is given.
Date: August 12, 1965
Creator: Beatty, Robert W.
Partner: UNT Libraries Government Documents Department