Aeroelastic behavior of a pair of thin circular cylindrical shells in staggered arrangement

A series of wind-tunnel tests have been conducted on the aeroelastic characteristics of a pair of closed-ended, thin, circular cylindrical shells of identical size in a staggered arrangement. The streamwise and transverse separations between the centers of the two cylinders were varied in the range from 0 to 2.5D and from 0.5 to 1.5D, respectively, with D being the cylinder diameter. Detailed measurements of the prebuckling and buckling behavior of the downstream cylinder were made with a variety of elastic cylinders in both smooth and turbulent flows. Wind pressure distributions around the downstream cylinder were also measured. The results indicate that the prebuckling deflection can be predicted by the linearized Donnell's equations with a reasonable degree of accuracy, though the deflection is extremely sensitive to the relative position of the two cylinders. When the downstream cylinder is partially immersed in the wake of the upstream cylinder, the pressure distribution in the circumferential direction exhibits a marked asymmetry with respect to the shifted stagnation point and the buckling pressure of the cylinder is relatively low compared to that of an isolated cylinder. Furthermore, a brief examination was made of the relation between buckling pressure and circumferential Fourier components in the pressure distribution, by using the methods of multivariate statistical analysis.