Numerical Simulation of On-Road Wind Conditions for Interior Wind Noise of Passenger Vehicles

Traditionally vehicles are designed for wind noise under ideal steady wind conditions. But, passenger comfort is affected by high modulation of cabin noise while cruising in traffic due to variations of instantaneous wind speed and direction from driving through large-scale turbulence. In consequence, designing a vehicle for the best performance in a low-turbulence wind tunnel may lead to issues during on-road conditions. To predict the interior noise corresponding to on-road turbulence, a simulation approach is proposed combining an upstream turbulence flow simulation with an SEA vehicle model. This work is an extension of existing well validated procedures for steady wind conditions. Time-segmented transient loads on panels and steady-state structural acoustics transfer functions are combined, producing interior noise results for a series of overlapping time segments. This interior noise prediction, as a function of time, captures the modulation of wind noise results, which are then visualized using a spectrogram, plotting sound pressure level indicated by color as a function of time and frequency bands. Audio signals are also created from the interior noise results, allowing detailed signal analysis from this simulation. This capability enables designers to reduce wind noise modulation in time caused by on-road turbulence, improving speech intelligibility and passenger comfort.