Abstract: A flexible duct for conveying a gaseous flow, with the duct useable as the flexible nozzle in a wind tunnel. The duct includes a flexible plate member which is attached at the downstream end to a frame support member, with the upstream end of the flexible plate member being slideable and pivotable upon a member attached to the frame support member. A plurality of swing link members in spaced-apart relationship are pivotally connected at one end to the flexible plate member, and pivotally connected at the other end to a translatable and rotatable cradle-like member which is supported by crank members from the frame support member. An actuator is used to selectively move the cradle-like member. The resultant movement of the cradle-like member causes the flexible plate member to deflect, resulting in predetermined contours (and profiles) of the flexible plate member.

Abstract: An apparatus is disclosed for achieving interference-free fluid velocity distributions in the plane of the walls of a subsonic wind tunnel. Adjustable slats having longitudinal baffles therebetween make up the test section walls, excluding the ground plane, and extend upstream and downstream of the vehicle to be tested. Static pressure measurements along the centerline of each slat provide information that enables calculation of the slat contour required to achieve close matching of the streamlines within the tunnel to those occurring on the road.