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

Abstract

As the vehicle and wind speeds and directions change, the unsteady flow creates non-stationary wind noise. 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 used 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 based on provided wind profiles. A reference wind noise measurement is then filtered 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 and one stationary reference measurement are used to estimate the relationship between sound power and wind speed. The accuracy of the estimation was validated by comparing wind noise simulations with wind tunnel measurements, A further improvement is to use partially correlated white noise signals to simulate binaural sounds that have a similar coherence structure between the left and right ear sounds to that observed in binaural measurements in the vehicle.