Effect of geometric parameters on the noise generated by rod-airfoil configuration

TL;DR

This study explores how the geometric parameters of rod diameter and distance to the airfoil affect noise generation in rod-airfoil setups, using combined experimental and numerical methods for validation.

Contribution

It introduces a comprehensive numerical approach with DDES and SLA SGS for simulating aeroacoustic noise, validated against experimental phased microphone array data.

Findings

Numerical results agree well with experimental data on far-field acoustics.

Geometric parameters significantly influence noise levels.

The combined approach improves prediction accuracy of aeroacoustic noise.

Abstract

This paper investigates the effect of the geometric parameters -- rod diameter and the distance between the rod and the airfoil -- on the noise generated by rod-airfoil configuration using experimental and numerical techniques. The numerical simulations are carried out using the low-dissipation up-wind scheme and the Delayed-Detached-Eddy Simulation (DDES) approach with Shear-Layer Adapted (SLA) sub-grid length scale (SGS) for a faster transition between RANS and LES. A dual-time stepping strategy, leading to second-order accuracy in space and time, is followed. The Ffowcs-Williams and Hawkings (FWH) technique is used to post-process the pressure fluctuations to predict the far~field acoustics. A corresponding detailed experimental analysis, carried out using phased microphone array techniques in the aeroacoustic wind tunnel at the Brandenburg Technical University at Cottbus, is used for the validation of the numerical method. The key objective of the analysis is to examine the influence of the parameters of the configuration on the noise generation. The results show reasonable agreement with the experimental data in terms of far-field acoustics.