Wind-Tunnel and On-Road Wind Noise: Comparison and Replication 2013-01-1255
A KIA Soul was instrumented to measure the relative velocity
(magnitude and yaw angle) at the front of the vehicle and in-cabin
sound at a location close to the side glass near the A-pillar
vortex impingement. Tests were conducted at a proving ground under
a range of conditions from low wind conditions (~3 m/s) to moderate
(7-8 m/s) wind speeds. For any given set of atmospheric conditions
the velocity and sound data at any given position on the proving
ground were noted to be very repeatable, indicating that the local
wakes dominated the "turbulent" velocity field.
Testing was also conducted in an aeroacoustic wind tunnel in
smooth flow and with a number of novel turbulence generating
methods. The resulting sounds were analyzed to study the modulation
at frequencies likely to result in fluctuation strength type noise.
The wind-tunnel results were compared to the on-road measurements
to investigate the potential of generating repeatable and
controllable turbulence in a wind tunnel which replicates the
modulated noise experienced on-road.
The results showed that the novel methods used do increase the
modulation significantly and subjective analysis indicates that the
modulation generated was similar to that experienced on-road.
Analytical analysis of the same data showed the extent of the
modulation and it was found that that the magnitude of the
modulation was too high at low modulation frequencies and too low
at higher frequencies. It is believed that with further development
of the wind-tunnel techniques the distribution over the modulation
frequencies of interest could be improved.