Spanwise correlation of aerodynamic forces on oscillating rectangular cylinder

•The amplitude can improve the spanwise correlation of the forces on bluff cylinder.•The spanwise correlation is studied with the wind exceeding lock-in regime.•The pattern of vibration and amplitude may determine the correlation of the forces•An approach using energy method is proposed to study the effect of amplitude.•The incident angle and Reynold number have greater influence for vertical motion.

The aerodynamic forces (lift and moment) on oscillatory rectangular cylinder with side ratio B/D=5 are investigated by synchronized surface pressure measurement and forced motion technique. The effects of amplitude of vibration, incident angle and Reynolds number on the spanwise correlation of aerodynamic loading are studied. Results show that aerodynamic forces along the span are not fully correlated, which indicates that the application of the strip assumption may overestimate the overall aerodynamic loading on large-span structures, and consequently may result in a large error margin in evaluation of flutter and aeroelastic response. It is also shown that the pattern of vibration and its amplitude play a significant role in dektermining the spanwise correlation of the aerodynamic forces, including the motion-induced force and the vortex-induced force. Furthermore, the effects of the incident angle and Reynolds number are related with the vibrating pattern, and should not be negligible in some cases.

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