Peening Effect On Flow Resistance Of Air

Author:  Iida, K. and Miyazaki, K.
Source:  Conf Proc: ICSP-4, (p. 73-82)
Doc ID:  1990048
Year of Publication:  1990
Abstract:  
Shot peening produces many dents on the surface of work material. Geometry of dent is a segment of sphere similar to dimple of golf ball, therefore peened surface may be affects the flow resistance of air. Drag coefficient was measured in air flow on polished and various peened specimens. Used shot diameter are 1.00 - 2.38 mm. The velocities of air flow are 5 - 25 m/s. Raynold's number are 2.98 x 10(4) - 1.49 x 10(5). The surface roughness of specimen are 0.1 - 32.5 um produced by polishing and shot peening. Area coverage of shot peened specimens are 21 - 100%. The pitches of fringe to fringe of dent obtained from profile records on peened surface are examined. The relation between resistance (D) of air flow and drag coefficient (Cd) is as follows: D = Cd . K . 1/2 pV where K: geometry of specimen p, V: density and velocity of air Drag coefficient of shot peened specimen decreased 2.4 - 11 % compared with polished one, and decreased 0.81 - 8.1 % by area coverage and also decreased 0.86 - 3.4 % by pitch of fringe. Descriptors: Shot peening; Drag coefficient; Flow resistance; Area coverage