A review of transverse curvature effect on friction force and leading-edge flow

The paper reviews the transverse curvature effect on the friction force on and the leading-edge flow around a cylinder subjected to axial flow. Skin friction coefficient (C-f) on the cylinder surface could be predominant functions of Reynolds number (Re-a, based on cylinder radius a), transverse curvature (a(+), normalized by friction velocity U-tau), and boundary-layer thickness ratio (delta/a). The relationships between C-f, Re-a, a(+), and delta/a are analyzed, established, and presented in the form of empirical formulations. The C-f at Re-a <= 2 x 10(3) is mainly dependent on delta/a while that at Re-a > 2 x 10(3) is largely contingent on Re-a. The gaps of research into the axial flow cylinder are pointed out, namely, the literature lack the experimental study on large transverse curvature (small a(+)).y