Improvements to a Method to Simulate Non-Stationary Wind Noise in Vehicles 2023-01-1122

Unsteady flow conditions over vehicles creates wind noise. As the vehicle and wind speeds and directions change, the wind noise in the vehicle also changes. To investigate people’s perceptions of non-stationary wind noise, a method to simulate the non-stationary wind noise is needed. Previously, a method was developed that uses stationary recordings taken at several speeds and directions to create a set of sound pressure level predictions in each one-third octave band that are a function of wind speed and direction. These functions are used to create time-varying filters that are used in simulations of non-stationary wind noise. These time-varying filters can be used with a reference measurement, white noise, or pink noise to produce the sounds. A drawback of this method is that many stationary wind condition measurements are needed to form accurate sound pressure level functions, which can be time consuming. A method requiring fewer measurements was investigated. At each yaw angle one non-stationary noise measurement where the speed is swept from the lowest to the highest speed and one stationary reference measurement are used. By combining results at all different yaw angles, the sound pressure level functions in the one-third octave bands can be generated. A further improvement to the previous wind noise simulation method is to simulate binaural sounds that have the similar coherence structure between left and right ear sounds observed in binaural measurements in the vehicle. Three independent sources are used: one at low frequencies for both ears and two at high frequencies, one for each ear. The wind noise simulations are compared to stationary and non-stationary measurements taken in the car in the wind-tunnel.