Sphere drag at transonic speeds and high Reynolds numbers

Abstract

M of sphere drag have been made in the AEDC aeroballistics range G over the Maeh number range 0.9 A/o, <1.4 at a Reynolds number of approximately 10. These values of sphere drag were found to be larger than the values derived from the experimental summary curves presented in Ref. 1. The change in sphere drag with Mach number near Mach 1, as well as with Reynolds number in excess of 10, is significant and care is required in establishing summary curves. On the basis of these more recent measurements and those contained in Refs. 2 and .3, the summary curves presented in Ref. 1 have been reevaluated. A plot of the revised values of sphere drag f or 5 x 10 </?£«, <10 and 0.1 <M^ < 1.75 is presented in Fig. 1. The difference between the previous and present values of sphere drag coefficient at M^ =0.955 (Fig. 1) is representative of the changes that have been made, in the Mach number range of 0.8 to 1.5. Sphere drag coefficient is shown to increase with increasing Reynolds number for 10 <Rex ^ 10 for Mach numbers ranging from 0.9 to 1.75 (Fig. 1).