Three dimensional modelling of sound absorption in porous asphalt pavement for oblique incident waves
Regular paper
University of Twente
Tuesday 2 june, 2015, 09:00 - 09:20
0.2 Berlin (90)
Abstract:
Tyre-road noise can be reduced by increasing the sound absorption of the pavement.
Properties that influence the sound absorption are for example the porosity, the
stone size, the type of bitumen and fillers. A ground impedance model can be used
to predict the acoustical properties of the pavement.
Since a rolling tyre will radiate noise in all directions, the angle of incidence
should be accounted for. Also, the sound waves will reflect and scatter on the
stones within the pavement, which can be best described by a nonlocally reacting
surface.
A numerical model has been developed which can predict the three-dimensional sound
field in and above the porous asphalt pavement and the absorption coefficient for
oblique incident sound waves. The modelling approach is a combination of an
analytical and a finite element approach, including both the viscothermal effects
and the scattering effects.
In this paper the modelling approach is described and simulation results for
various three-dimensional stone configurations are given. The developed model can
be validated by measurements with a small microphone array, which can measure the
absorption coefficient for oblique incident sound waves.