Accession Number : ADA183359


Title :   A Flow Visualization Study of Laminar/Turbulent Transition in a Curved Channel


Descriptive Note : Master's thesis


Corporate Author : NAVAL POSTGRADUATE SCHOOL MONTEREY CA


Personal Author(s) : Siedband, Marc A


Full Text : https://apps.dtic.mil/dtic/tr/fulltext/u2/a183359.pdf


Report Date : Mar 1987


Pagination or Media Count : 126


Abstract : Laminar/turbulent transition was studied as it occurs in a newly constructed curved channel of rectangular cross section. The channel is 1.27 centimeters high by 50.8 centimeters wide (0.5 in. x 20 in.), aspect ratio of 40 to 1, with a concave surface radius of curvature of 60.96 centimeters (24 in.). Mean velocities for air in the channel range from 1.40 to 3.89 m/sec, which corresponds to Dean number and hydraulic Reynolds number ranges of 167 to 4651 and 2,231 to 6,173, respectively. Flow visualization from a smoke ire shows changes in the behavior and appearance of a smoke trace illuminated in the radial plane with varying Dean number and varying channel location. In some cases, these smoke trace patterns show distortion similar to what would be expected if pairs of counter-rotating vortices are present. A map of vortex stability as channel location and Dean number were varied was constructed from analysis of smoke trace photographs. Keywords: Dean vortices; Taylor Gortler vortices; Dean number; Rectangular curved channel; Secondary flow; Laminar flow; Concave curvature; Convex curvaturre.


Descriptors :   *CHANNEL FLOW , *FLOW VISUALIZATION , *TURBULENCE , *VORTICES , ASPECT RATIO , CHANNELS , CONCAVE BODIES , CONVEX BODIES , COUNTERROTATION , CROSS SECTIONS , CURVATURE , DISTORTION , HYDRAULICS , LAMINAR FLOW , PATTERNS , PHOTOGRAPHS , RADIUS(MEASURE) , RECTANGULAR BODIES , REYNOLDS NUMBER , SECONDARY FLOW , SMOKE , SURFACES , THESES , TRANSITIONS


Subject Categories : Test Facilities, Equipment and Methods
      Fluid Mechanics


Distribution Statement : APPROVED FOR PUBLIC RELEASE