An experimental effort to characterize the broadband flow-induced lift forc
es on a spherical body that is towed underwater is described. The body itse
lf is the transducer which is comprised of a small geophone encased in a ne
ar-neutrally-buoyant sphere, 7.62 cm in diameter. The research described in
this paper quantifies the flow-induced unsteady lift force signal as a fun
ction of the sphere diameter Reynolds number (7620 < Re < 34290) and the St
rouhal number (1.5 < St < 30). It is found that the broadband flow-induced
unsteady lift forces are proportional to the product of an area and the dyn
amic pressure of the flow, as expected. These data are compared to similar
data measured previously on a finite-length, right-circular cylinder in cro
ss flow. This comparison indicates that the cylindrical body creates more u
nsteady side force than does the spherical one, particularly at the lower e
nd of the Strouhal number range. (C) 1998 Academic Press.