Noise Generation by Tandem Cylinders of Different Diameter in Cross-Flow

Kurzfassung

The noise generation by two circular cylinders placed in a tandem configuration is of large interest in aeroacoustic research, as it constitutes a simple model for technical applications like parts of the landing gear of aircraft or the protective guard grille of axial fans. The resulting tonal noise depends on parameters such as the diameter of the cylinders and their spacing, the angle between the cylinders with respect to the flow and the flow velocity and inflow turbulence parameters. In a recent study in a small aeroacoustic wind tunnel facility, the far-field noise generated by parallel tandem cylinders with different diameter was measured for various cylinder spacings, allowing for the analysis of the effect that the wake impingement of the upstream cylinder on the downstream cylinder has on the tonal noise. In the paper, results from these experiments are presented and discussed together with results from flow field measurements that enable a better understanding of the physical noise generation mechanisms.