Numerical Study of Aerodynamic Sound and Spatial Coherence Lengths for Circular Cylinders in Sub Critical Flow Regime

Numerical studies were performed to establish relationship between far field noise and spatial coherence length (LC) for circular cylinders in the subcritical flow regime. Hybrid methods involving Large eddy simulations and acoustic analogy was used to estimate aerodynamic noise from circular cylinders for various Reynolds numbers (Re) between 3900 to 145000. Simulations were performed for shorter span lengths and correction technique based on LC was employed to estimate sound in the far field for infinitely long cylinders. A comprehensive database for LC for various Re in the subcritical flow regime is intended from the study, which could be used to compute far field sound for any Re in the mentioned regime. As experiments on flow-induced noise are limited, the effective use of computation techniques is of much importance for the research in flow-induced noise.