FLOW CHARACTERISTICS AROUND 2 PARALLEL ADJACENT SQUARE CYLINDERS OF DIFFERENT SIZES

This paper presents the results of the aerodynamic forces and vortex s heddings of two square cylinders in side-by-side arrangement of size r atio 2:1 at subcritical flow regime. Flow measurements were carried ou t at transverse spacing of 1.12 less than or equal to T/D less than or equal to 2.5. The gap side shear layer of the large cylinder reattach es to its inner face for small separation, while the gap side shear la yer of the small cylinder reattaches to its inner face for larger sepa ration. The distributions of aerodynamic forces reveal that maximum pr essure loading on the small cylinder occurs at a separation of T/D = 1 .75. The coefficient of moment C-M remains negative for the different transverse spacings studied and a point of inflexion is found at T/D = 1.25. The trajectories of the vortices from the cylinders and the mea n and fluctuating velocities of the wakes at x/D = 2.0 show that the h ow is skewed towards the small cylinder. No bistable flow is found wit hin the transverse spacing studied.