ABSTRACT
The generation o f noise by flow over solid bodies is o f interest in a number o f engineering applications. Although the noise generated by arrays o f cylinders in cross flow has been investigated by numerous authors (e.g. Ziada et al. 1989, Belvins & Bressler 1987, Fitzpatrick 1985), there has been little reported on the noise emanating from smaller groups o f cylinders particularly in unbounded flows. The study o f two tandem cylinders (i.e. one behind the other) in a cross flow provides a useful vehicle to develop an understanding o f the mechanisms o f flow/acoustic interactions. The characteristics o f the flow around two cylinders has been extensively reviewed by Zdravkovich (1977). Measurements reported by Fitzpatrick & Nitti (1997) have shown the development o f harmonics in the interflow region between two tandem cylinders in cross flow and that noise at twice the vortex shedding frequency is radiated from the downstream cylinder with an additional source in the mid wake region. Fitzpatrick & Valeau (1998) have suggested that the multiple harmonics are a consequence both o f non linear shear layer interactions and o f vortex impingement and deformation on the downstream cylinder and subsequent propagation upstream.
