Enhanced Capabilities of the Aeroacoustic Wind Tunnel Braunschweig

The Aeroacoustic Wind Tunnel Braunschweig is DLR’s small, high-quality test facility for aero-acoustic noise measurements. After years of mainly pure acoustic measurements the actual and the future research work will focus on the combined acquisition of aerodynamic and acoustic data. In order to prepare the AWB for the next decades a modernization of this wind tunnel was initiated targeting the enhancement of the aerodynamic properties while the excellent acoustic properties should at least be preserved. Based on the assessment of AWB’s original acoustic and aerodynamic characteristics a new acoustic wall-treatment in combination with new sound absorbing turning vanes was installed in the flow circuit. In order to prevent the highly bended downwash flow caused by airfoils tested at high angles of attack from impinging on the test section floor a new collector was installed that can be moved upstream and vertically down. Finally the driven efforts resulted in an increase of the maximum flow velocity of about 8% while first the background noise levels for an empty test section were preserved and second the use of the adaptive collector lead to a significant background noise reduction for airfoil tests.