A Model for Diffracting Elements to Reduce Traffic Noise
Invited paper
University of Twente
Tuesday 2 june, 2015, 13:40 - 14:00
0.2 Berlin (90)
Abstract:
In the Netherlands there is a great demand for noise reducing measures to
fulfill the noise legislation and to reduce the annoyance of traffic noise.
Silent pavements and noise barriers are well-known, but are there other
alternative or additional measures?
The company 4Silence developed a sound diffracting element (Whisstone); a
concrete element with cavities that is placed alongside the road at the same
level as the road surface. The diffracting element deflects tyre-road noise in
an upward direction, creating a zone of noise reduction behind the element. It
can therefore act as a complement to existing noise-reducing measures and can
be optimized for maximum noise reduction.
Based on a finite element model, it is possible to assess the performance of
the diffracting elements. However, these models are impractically large to
optimize the geometry for maximum sound reduction. We therefore developed a
very fast, semi-numerical model, which makes optimization of the geometry
feasible. In this paper we present this semi-numerical model and report the
validation of its correctness by comparison with a finite element model.
In an accompanying paper of J. Hooghwerff, a measurement setup and actual
experimental results for the diffracting elements will be presented, showing
that this innovation can increase noise reduction up to 4 dB.