Water Tunnel Flow Visualization Study Through Poststall of 12 Novel Planform Shapes

Download or read book Water Tunnel Flow Visualization Study Through Poststall of 12 Novel Planform Shapes written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-07-23 with total page 130 pages. Available in PDF, EPUB and Kindle. Book excerpt: To determine the flow field characteristics of 12 planform geometries, a flow visualization investigation was conducted in the Langley 16- by 24-Inch Water Tunnel. Concepts studied included flat plate representations of diamond wings, twin bodies, double wings, cutout wing configurations, and serrated forebodies. The off-surface flow patterns were identified by injecting colored dyes from the model surface into the free-stream flow. These dyes generally were injected so that the localized vortical flow patterns were visualized. Photographs were obtained for angles of attack ranging from 10' to 50', and all investigations were conducted at a test section speed of 0.25 ft per sec. Results from the investigation indicate that the formation of strong vortices on highly swept forebodies can improve poststall lift characteristics; however, the asymmetric bursting of these vortices could produce substantial control problems. A wing cutout was found to significantly alter the position of the forebody vortex on the wing by shifting the vortex inboard. Serrated forebodies were found to effectively generate multiple vortices over the configuration. Vortices from 65' swept forebody serrations tended to roll together, while vortices from 40' swept serrations were more effective in generating additional lift caused by their more independent nature. Gatlin, Gregory M. and Neuhart, Dan H. Langley Research Center WATER TUNNEL TESTS; FLOW VISUALIZATION; FLOW DISTRIBUTION; FREE FLOW; PLANFORMS; WING PROFILES; AERODYNAMIC CONFIGURATIONS; ANGLE OF ATTACK; ROLL; DYES; FLAT PLATES; FOREBODIES...