Calculation of Tyre Noise Radiation with a Mixed Approach

The radiation of tyre noise is computed with a mixed integral/ ray tracing approach called GRIM. It is simply an integral over the vibrating tyre, of the product of the known velocity by the full Green function which takes into account all the multiple reflections and diffraction between tyre, ground and car body. This Green function is calculated by means of a beam tracing program named ICARE, which can deal with curved surfaces and multiple diffraction. This approach makes the link between tyre models and certification points well outside the car.