  Axisymmetric boundary layers are studied using integral analysis of the
governing equations for axial flow over a circular cylinder. The analysis
includes the effect of pressure gradient and focuses on the effect of
transverse curvature on boundary layer parameters such as shape factor ($H$)
and skin-friction coefficient ($C_f$), defined as $H = \delta^*/\theta$ and
$C_f = \tau_w/(0.5\rho U_e^2)$ respectively, where $\delta^*$ is displacement
thickness, $\theta$ is momentum thickness, $\tau_w$ is the shear stress at the
wall, $\rho$ is density and $U_e$ is the streamwise velocity at the edge of the
boundary layer. Relations are obtained relating the mean wall-normal velocity
at the edge of the boundary layer ($V_e$) and $C_f$ to the boundary layer and
pressure gradient parameters. The analytical relations reduce to established
results for planar boundary layers in the limit of infinite radius of
curvature. The relations are used to obtain $C_f$ which shows good agreement
with the data reported in the literature. The analytical results are used to
discuss different flow regimes of axisymmetric boundary layers in the presence
of pressure gradients.
