Calculation process with Lattice Boltzmann and Finite Element methods to choose the best exterior design for wind noise 2019-01-1471
Authors : Guillaume BAUDET, Cécile DUTRION, Rémi LORENZI, Félix GENDRE, Shanshan GENG Renault
Automotive wind noise is a complex phenomenon. Noise in the cabin depends of:
- The exterior loading due to the flow around the vehicle
- The transfer loss of seals and panels
- The acoustic transfer function of the cabin
Each part of this cascading must optimized to have a good final performance.
So the exterior design is a key parameter because it influence the loading (pressure field) on the vehicle panels and seals. For some years, we know that the exterior loading is split in two parts:
- Hydrodynamic (or turbulent) loading with high wave number pressure field
- Acoustic loading with low wave number pressure field
In this paper, we present a calculation process which enables to predict the acoustic source created by the lateral window at high speed which has a major contribution to the interior noise.
It is based on a CFD calculation of the complete car with the Lattice Boltzmann Method to calculate in one pass the hydrodynamic and the acoustic pressure. The pressure field is the input of a vibro acoustic finite element model of the window. This model calculates the vibration and the acoustic source created by the window.
Extensive experiments carried out on several Renault vehicles demonstrate the ability of the method to choose the good design. However, the procedure is simple enough to be easily applied at each design milestone of a new vehicle, to help to choose the best design.