Active Control of Counter Rotating Open Rotor Interior Noise

Abstract

Future aircrafts have to meet the restrictive fuel consumption guidelines of the European Committee. Therefore lightweight materials like carbon fibre reinforced plastics (CFRP) and new engine concepts are investigated. Counter Rotating Open Rotors (CROR) are a very promising approach for a more efficient aircraft. But in combination with a CFRP fuselage the interior noise levels will be increased dramatically because of the high pressures on the fuselage and the low transmission loss of CFRP. In this work active concepts as a lightweight compliant solution will experimentally investigated to improve the acoustic comfort of future aircrafts. A typical aircraft sidewall panel is therefore realized in a sound transmission loss facility and will be controlled actively by a feedforward control system. The panel is excited by a typical multi tonal pressure field which is generated by a speaker array. This preliminary study shows that an active structural acoustic control system can effectively improve the acoustic comfort inside the cabin.