Aerodynamics of pointed forebodies at high angles of attack

Helical-Groove and Circular-Trip Effects on Side Force

“…It is obvious from Fig. 15 that the present helical groove is less effective in reducing the side force than the helical trips of Modi et al 19 helical trip shows a reduction in the side force of as much as 60% of the clean ogive nose, whereas the symmetric helical trip of Rao 7 can reduce the side force to near zero. On the other hand, our helical-1/1 can only achieve at most a 51% side force reduction.…”

“…15, where the side forces of helical-1/1, trip-3.5D, and the clean ogive nose at u = 0 deg are compared with the results of Rao 7 and Modi et al 19 In Rao's experiment, 7 a pair of solder wires were deployed helicallyand symmetricallyon the two sides of an ogive nose model. On the other hand, in the Modi et al, 19 investigation, a helical trip with a pitch of 3 cm was installedon the nose of a cone nose cylinder to suppress the side force. It is obvious from Fig.…”

Three-dimensional boundary layer and vortex wake over a cone at high angle of attack: study of asymmetries

“…Different means are used to reduce asymmetries or to remove them: e.g., roughness on the pointed body surface can be used (Lamont and Hunt 1976;Ericsson and Reding 1981;Modi et al 1984); blunting near the nose, or adding modifying elements (such as strakes, helical trips, nose booms .... ) are worthy solutions (Modi et al 1984;Stahl 1990;Rao 1977;Coe et al 1972;Sarpkaya 1966). Finally, the lateral forces and moments can be suppressed by blowing near the nose (Cornish and Jenkins 1978;Skow and Peake 1982;Mourtos and Roberts 1987).…”