Acoustics of a Helmholtz Resonator Aligned Parallel with Flow: A Computational Study VS. Experiments

Abstract

Acoustic attenuation of a Helmholtz resonator (HR) placed parallel to the flow path is investigated computationally with and without mean flow and compared with experimental results. The time-dependent flow field is determined by solving three-dimensional unsteady, laminar/turbulent, compress-ible Navier-Stokes equations using Pressure-Implicit-Splitting- of-Operators algorithm of STAR-CD. Computations are performed by di erent finite difference schemes such as central and upwind for momentum equation. Predictions with central differencing, a blending (with upwind) factor 0.5, and fine mesh reveal results that are consistent with the experimental observations. The effect of flow on the acoustic attenuation characteristics of HR has been illustrated both computationally and experimentally. The predictions for transmission loss exhibit reduced attenuation at elevated flow rates. Index