Acceleration or deceleration in the flow that moves around the cylinder causes significant change to the structure of the boundary layer and, correspondingly, change to the position of the point of boundary layer separation: during acceleration of the flow around the cylinder ([partial derivative]W/[partial derivative][tau]) > 0, the point of separation shifts backwards, causing a decrease in aerodynamic trail width and as a result profile drag
caused by viscous forces in the flow (the coefficient of profile drag
[C.sub.x] decreases); during deceleration in the flow ([partial derivative]W/[partial derivative][tau]) < 0, the point of boundary layer separation shifts forward, widening the aerodynamic trail behind the cylinder and increasing profile drag
It computes side-force lift, vortex drag, profile drag
, weight, center of gravity location as measured from the root leading edge, center of gravity as measured vertically from root location, and other performance parameters.