Effect of spacing between two adjoining square cylinders on flow around two-dimensional square cylinder row supported by elastic plate springs

In this paper we describe the effect of spacing between two adjoining square cylinders on flow around two-dimensional square cylinder row supported by plate springs. The experiment was carried out in an N. P. L. blow-down-type wind tunnel with a working section of 500 mm × 500 mm× 2 000 mm, and a Reynolds number of 9.4 × 10³. The frequency of vortex shedding from the square cylinder, the displacement of the vibrating square cylinder, and the time mean and fluctuating surface pressure distributions on the square cylinder were measured. Consequently it was found that (i) vortex shedding from square cylinders occurs in the range of spacing ratio S/D≥1.7, while there is two patterns regarding the existence of vortices shedding from square cylinders in the range of 1.7 ≤S/D≤2.5, (ii) the displacement of vibrating cylinder due to the shedding vortices attains maximum at S/D=3, (iii) the fluctuating pressure distribution on the surface and fluctuating lift by frequency of shedding vortices become largest at S/D=3.