Application Of High Resolution Airload Calculations To Helicopter Noise Prediction

Recent studies of blade/vortex interactions have resulted in the development of aerodynamic models with which the very detailed loading data necessary for noise predictions can be calculated. The methods employed not only obviate the need for some of the simplifying assumptions that have previously reduced the precision and sensitivity of acoustic calculations but also achieve this improvement at little cost in computing power. Although development of the aeroacoustic techniques is not yet complete it has been established that highly detailed predictions can be made as a matter of routine. Applications of these techniques in light of the growing requirement for noise prediction methods and the penalty incurred by manufacturers if they are not available at the design stage of a new helicopter project are described.