Vibro-Acoustic Simulation of Side Windows and Windshield Excited by Realistic CFD Turbulent Flows Including Car Cavity 2012-01-1521

Nowadays, the interior vehicle noise due to the exterior aerodynamic field is an emerging topic in the acoustic design of a car. In particular, the turbulent aerodynamic pressure generated by the air flow encountering the windshield and the side windows represents an important interior noise source.

As a consequence PSA Peugeot Citroën is interested in the numerical prediction of this aerodynamic noise generated by the car windows with the final objective of improving the products design and reducing this noise. In the past, several joint studies have been led by PSA and Free Field Technologies on this topic. In those studies an efficient methodology to predict the noise transmission through the side window has been set up. It relies on a two steps approach: the first step involves the computation of the exterior turbulent field using an unsteady CFD solver (in this case EXA PowerFlow). The second step consists in the computation of the vibro-acoustic transmission through the side window using the finite element vibroacoustic solver Actran.

The present paper extends this methodology for the handling of multiple windows, i.e., the two front side windows and the windshield. The complete car cavity is modeled as well. First, a complete description of the method and the finite element model is provided, from the boundary conditions to the different components involved, like the windows, the seals and the car cavity. The total wind noise level results and the relative contributions of the different windows are then presented and compared to measurements for a real car model. The influence of the flow yaw angle (0° versus 10° orientation) is also assessed.