Effect of tactile vibration on annoyance to synthesized propfan noise

Abstract

A research program at NASA-Langley Research Center is being conducted to provide design information that maximizes passenger comfort for proposed propfan aircraft. Particular emphasis in this study is being placed on predicting noise and vibration environments and the resultant passenger acceptability. Previous ride quality research of this program has indicated that vibrations of sufficient intensity to produce whole body movements (at frequencies less than 30 Hz) cause passenger discomfort and annoyance. Within this complex interior environment, this type of vibration interacts additively with noise to produce discomfort. However, recent questions have arisen concerning the effect of high frequency tactile vibration (i.e., greater than 30 Hz) on passenger reactions. The current study addressed this question through obtaining passenger reactions to a wide range of noise and tactile vibration environments. The investigation was conducted in the passenger ride quality simulator located at the NASA-LaRC using 96 subjects who evaluated either synthesized propeller noises only, or these noises combined with seat/arm vibration. The noises ranging from 80–100 dB consisted of a turbulent boundary layer noise with a factorial combination of five blade passage frequencies (50–200 Hz), two harmonic rolloffs, and three tone/noise ratios. The results indicate that passenger reaction (annoyance) to noise is not significantly changed in the presence of tactile vibration.