Motion-related body-force functions in two-dimensional low-speed flow

The paper examines two-dimensional force functions useful in the wind-respo nse analysis of bluff bodies, such as bridges, that are elongated in the ac ross-wind direction. Airfoil-type theoretical 2-D indicial, admittance, and oscillatory force functions and their interrelationships are first recalle d for their analogical value. Following this, a spectral force expression i s developed for the lift on a bluff section due to a cross-wind with a vert ical turbulence component. The expression proposed involves an aerodynamic admittance that is based upon measured flutter derivatives for the bluff se ction plus information on the coherence of vertical turbulence in the atmos pheric boundary layer. (C) 2000 Academic Press.