Title: Application of the passive control of shock wave to the reduction of high-speed impulsive noise

Authors: Piotr Doerffer, Oskar Szulc

Addresses: Department of Transonic Flows, Institute of Fluid-Flow Machinery, Polish Academy of Sciences, Fiszera 14, 80-952 Gdansk, Poland. ' Department of Transonic Flows, Institute of Fluid-Flow Machinery, Polish Academy of Sciences, Fiszera 14, 80-952 Gdansk, Poland

Abstract: Strong, normal shock wave, terminating a local supersonic area on an airfoil (or helicopter blade), not only limits aerodynamic performance but also becomes a source of a high-speed impulsive (HSI) noise. The application of a passive control system (a cavity covered by a perforated plate) on a rotor blade should reduce the noise created by a moving shock. This article covers details of the numerical implementation of the Bohning/Doerffer transpiration law into the SPARC code and includes a validation against the experimental data obtained for the ONERA transonic nozzle with a flat wall. The passive control device is then applied numerically on a helicopter blade in high-speed transonic hover conditions to weaken the shock wave – the main source of HSI noise.

Keywords: shock waves; passive control; perforated walls; transpiration; helicopter rotors; transonic hover conditions; high-speed impulsive noise; airfoils; helicopter blades; transonic nozzles.

DOI: 10.1504/IJESMS.2011.038751

International Journal of Engineering Systems Modelling and Simulation, 2011 Vol.3 No.1/2, pp.64 - 73

Published online: 21 Mar 2015 *

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