Installation effects of a propeller mounted on a wing with Coanda flap

Abstract

The effect of installation on propeller noise was investigated. The chosen configuration consists of a nine bladed propeller in tractor configuration with a high-lift wing. Tests in the 3m acoustic wind tunnel DNW-NWB provided a valuable dataset for validation purpose of numerical codes. The CAA computations were based on a new highly efficient concept to represent the propeller as a perturbation consisting of rotating mass and momentum source distributions fed by CFD RANS data on the propeller blades, thus avoiding rotating grids. This approach will allow quantifying the installation effect at propeller driven aircraft especially to assess design changes with moderate computational effort. The validation showed good agreement. The particular tractor propeller/ high-lift wing arrangement showed excess noise due to the impingement of the propeller tip vortices on the (swept) wing nose and trailing edge flap.