Abstract
ABSTRACT
There is commonality between the lift /drag and aero-acoustic performance of a vehicle. Reducing the size of wakes not only reduces drag but also reduces the drag but also reduces the extent of aero-acoustic sources.
This paper describes both qualitative and quantitative aero-acoustic assessment over the side glass of a vehicle traveling at 130 km/hr. The wind tunnel used in this investigation is a ”low cost‘ facility normally used for lift/drag assessments and is considered, by aero-acoustic standards, to be a noisy tunnel.
The aero-acoustic assessment is compared with data acquired in an equivalent aero-acoustic (quiet) wind tunnel and is shown to be in close agreement up to a readily identifiable frequency limit. (a) Baseline 130 km/h The aero-acoustic assessment consists of flow visualizations followed by surface pressure measurements. The interior SPL is then calculated from this measured data. The adoption of this procedure is useful early in vehicle programmes where, for instance, the assessment is carried out over an aero-buck; a mock-up of the exterior surfaces of a vehicle that has no representation of the interior within which to measure interior SPL.