The Drag of Spheres in Rarefied Hypervelocity Flow PDF Download

Author: MAX. KINSLOW
Publisher:
ISBN:
Category :
Languages : en
Pages : 58

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Book Description
Drag of spheres was measured under hypersonic, cold-wall, support-free conditions in a nonreacting (vibration frozen) flow. Data were obtained for a nominal free-stream Mach 11 and for Reynolds numbers from 1 to 10 based on conditions immediately downstream of the bow shock and sphere diameter. These data were supplemented by measurements at a nominal Mach 10 where a conventional balance was used, and Reynolds numbers downstream of the shock as high as 10,000 were investigated in the cold-wall condition. The experimental results were analyzed both from the point of view of continuum flow with second-order viscous effects, and from the standpoint of a noncontinuum concept, taking account of first collisions between reemitted and free-stream molecules. Data from other sources were used to enlarge the present study and, in particular, to support the evaluation of K2 which represents the influences of vorticity, curvature, thick boundary layer, slip, and temperature jump. K2 was found to be negative in sign. The form of the derived equation for Cd/Cd(free molecular), where Cd is the drag coefficient, Cd/Cd free molecular appears to fit the experimental data over a considerable range of Knudsen numbers if a free constant is used in the expression for mean free path. (Author).