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The Effect of Compressibility on the Growth of the Laminar Boundary Layer on Low-Drag Wings and Bodies

Description: Report presenting a consideration of the development of the laminar boundary layer in a compressible fluid. Formulas are given for determining the boundary-layer thickness and the boundary-layer Reynolds number, which is a measure of the boundary-layer stability, for airfoils and bodies of revolution.
Date: July 1947
Creator: Allen, Julian & Nitzberg, Gerald E.
Partner: UNT Libraries Government Documents Department

A Concise Theoretical Method for Profile-Drag Calculation; Advance Report

Description: In this report a method is presented for the calculation of the profile drag of airfoil sections. The method requlres only a knowledge of the theoretical velocity distribution and can be applied readily once this dlstribution is ascertained. Comparison of calculated and experimental drag characteristics for several airfoils shows a satisfactory agreement. Sample calculatlons are included.
Date: February 1944
Creator: Nitzberg, Gerald E.
Partner: UNT Libraries Government Documents Department

Some fundamental similarities between boundary-layer flow at transonic and low speeds

Description: Report presenting an analysis of low-speed boundary-layer flow over airfoils at moderate angles of attack and Reynolds numbers of several million. Methods are developed for estimating the growth of the boundary layer in the regions of laminar separation and transition.
Date: June 1948
Creator: Nitzberg, Gerald E. & Crandall, Stewart
Partner: UNT Libraries Government Documents Department

A study of flow changes associated with airfoil section drag rise at supercritical speeds

Description: Report presenting a study of experimental pressure distributions and section characteristics for several moderately thick airfoil sections were made. The pressure distributions and section force characteristics of several moderately thick airfoil sections at Mach numbers above the drag-divergence Mach numbers were analyzed.
Date: February 1949
Creator: Nitzberg, Gerald E. & Crandall, Stewart
Partner: UNT Libraries Government Documents Department

The effect of compressibility on two-dimensional tunnel-wall interference for a symmetrical airfoil

Description: Summary: The effective change in the velocity of flow past a wing section, caused by the presence of wind-tunnel walls, is known for potential flow. This theory is extended by investigation of the two-dimensional compressible flow past a thin Rankine Oval. It is shown that for a symmetrical section at zero angle of attack the velocity increment due to the tunnel walls in the incompressible case must be multiplied by the factor 1/1-M^2 to take account of compressibility effects. The Mach number, M, corresponds to conditions in the wind-tunnel test section with the model removed (p. 1.).
Date: May 1943
Creator: Nitzberg, Gerald E.
Partner: UNT Libraries Government Documents Department

The interaction of boundary layer and compression shock and its effect upon airfoil pressure distributions

Description: Report presenting an investigation of the mechanism of interaction of compression shock with boundary layer. Shockless pressure distributions at supercritical Mach numbers were found to be accounted for by a marked thickening of the boundary layer for some distance ahead of a shock wave.
Date: April 10, 1947
Creator: Allen, H. Julian; Heaslet, Max A. & Nitzberg, Gerald E.
Partner: UNT Libraries Government Documents Department

The Effect of Compressibility on the Growth of the Laminar Boundary Layer on Low-Drag Wings and Bodies

Description: The development of the laminar boundary layer in a compressible fluid is considered. Formulas are given for determining the boundary-layer thickness and the ratio of the boundary-layer Reynolds number to the body Reynolds number for airfoils and bodies of revolution. It i s shown that the effect of compressibility will profoundly alter the Reynolds number corresponding to the upper limit of the range of the low-drag coefficients . The available data indicate that for low-drag and high critical compressibility speed airfoils and bodies of revolution, this effect is favorable.
Date: January 1943
Creator: Allen, H. Julian & Nitzberg, Gerald E.
Partner: UNT Libraries Government Documents Department

An empirically derived method for calculating pressure distribution at supercritical Mach numbers and moderate angles of attack

Description: Report presenting a procedure for calculating pressure distributions over airfoils at supercritical Mach numbers. Only the forward portion of the airfoil, where interaction between local boundary-layer thickness and local-pressure distribution is negligible, is considered in detail. The method cannot be considered definitive because it requires that certain characteristics regarding pressure distributions and geometric properties be known.
Date: April 1, 1947
Creator: Nitzberg, Gerald E. & Sluder, Loma E.
Partner: UNT Libraries Government Documents Department

A systematic investigation of pressure distributions at high speeds over five representative NACA low-drag and conventional airfoil sections

Description: From Summary: "Pressure distributions determined from high-speed wind-tunnel tests are presented for five NACA airfoil sections representative of both low-drag and conventional types. Section characteristics of lift, drag, and quarter-chord pitching moment are presented along with the measured pressure distributions for the NACA 65sub2-215 (a=0.5), 66sub2-215 (a=0.6), 0015, 23015, and 4415 airfoils for Mach numbers up to approximately 0.85. A critical study is made of the airfoil pressure distributions in an attempt to formulate a set of general criteria for defining the character of high speed flows over typical airfoil shapes. Comparisons are made of the relative characteristics of the low-drag and conventional airfoils investigated insofar as they would influence the high-speed performance and the high-speed stability and control characteristics of airplanes employing these wing sections."
Date: 1945
Creator: Graham, Donald J.; Nitzberg, Gerald E. & Olson, Robert N.
Partner: UNT Libraries Government Documents Department

Preliminary investigation of the delay of turbulent flow separation by means of wedge-shaped bodies

Description: Report presenting an experimental investigation of pyramidal, wedge-like bodies as devices for delaying separation of a turbulent boundary layer. Within certain limits, effective boundary-layer control was obtainable with wedges of different geometry, but the drag of the wedges was high, making it desirable to keep their size to a minimum. Greater maximum lift was obtainable by placing the wedges well forward along the chord and by allowing open spaces between adjacent wedges.
Date: March 1, 1951
Creator: McCullough, George B.; Nitzberg, Gerald E. & Kelly, John A.
Partner: UNT Libraries Government Documents Department

A preliminary investigation of the usefulness of camber in obtaining favorable airfoil-section drag characteristics at supercritical speeds

Description: Report presenting an investigation to determine the possibility of delaying at moderate or large lift coefficients the onset of the abrupt supercritical drag rise of an airfoil section by the use of camber. Results indicated that the addition of camber to the NACA 0010 airfoil leads to significant improvements in the drag characteristics at moderately supercritical speeds .
Date: October 7, 1949
Creator: Nitzberg, Gerald E.; Crandall, Stewart M. & Polentz, Perry P.
Partner: UNT Libraries Government Documents Department

The calculation of drag for airfoil sections and bodies of revolution at subcritical speeds

Description: Report presenting a method for calculating the drag, in a real compressible fluid and at subcritical Mach numbers, of airfoil sections at arbitrary life coefficients and of bodies of revolution at zero angle of attack. The values of drag coefficient are compared with values obtained for the same configurations by other methods. The differences between the results are found to lie withint he limits of accuracy of current experimental techniques.
Date: April 23, 1947
Creator: Heaslet, Max A. & Nitzberg, Gerald E.
Partner: UNT Libraries Government Documents Department