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Abnormal grain growth in M-252 and S-816 alloys

Description: An experimental investigation was carried out on air- and vacuum-melted M-252 and S-816 alloys to find conditions of heating and hot-working which resulted in abnormal grain growth. The experiments were mainly limited to normal conditions of heating for hot-working and heat treatment and normal temperatures of solution treatment were used to allow grain growth after susceptibility to abnormal grain growth was developed by various experimental conditions. Results indicated that small reductions of essentially strain-free metal were the basic cause of such grain growth.
Date: November 1957
Creator: Decker, R F; Rush, A I; Dano, A G & Freeman, J W
Item Type: Report
Partner: UNT Libraries Government Documents Department

Aerodynamic characteristics of a circular cylinder at Mach number 6.86 and angles of attack up to 90 degrees

Description: Pressure-distribution and force tests of a circular cylinder have been made in the Langley 11-inch hypersonic tunnel at a Mach number of 6.88, a Reynolds number of 129,000, and angles of attack up to 90 degrees. The results are compared with the hypersonic approximation of Grimminger, Williams, and Young and a simple modification of the Newtonian flow theory. An evaluation of the crossflow theory is made through comparison of present results with available crossflow Mach number drag coefficients.
Date: January 1957
Creator: Penland, Jim A
Item Type: Report
Partner: UNT Libraries Government Documents Department

Base pressure at supersonic speeds on two-dimensional airfoils and on bodies of revolution with and without fins having turbulent boundary layers

Description: An analysis has been made of available experimental data to show the effects of most of the variables that are more predominant in determining base pressure at supersonic speeds. The analysis covers base pressures for two-dimensional airfoils and for bodies of revolution with and without stabilizing fins and is restricted to turbulent boundary layers. The present status of available experimental information is summarized as are the existing methods for predicting base pressure. A simple semiempirical method is presented for estimating base pressure. For two-dimensional bases, this method stems from an analogy established between the base-pressure phenomena and the peak pressure rise associated with the separation of the boundary layer. An analysis made for axially symmetric flow indicates that the base pressure for bodies of revolution is subject to the same analogy. Based upon the methods presented, estimations are made of such effects as Mach number, angle of attack, boattailing, fineness ratio, and fins. These estimations give fair predictions of experimental results. (author).
Date: January 1, 1957
Item Type: Report
Partner: UNT Libraries Government Documents Department