Transition to turbulence on a cylinder in axial oscillatory flow
MetadataShow full item record
The transition to turbulence in oscillatory flow along a smooth cylinder, aligned axially with the ambient flow, was investigated through direct measurement of the wall shear stress, the phase lead of the maximum wall shear stress over the maximum free stream velocity, and the use of flow visualization with a laser light sheet. The results have shown that the Reynolds number clearly delineates the boundaries of the laminar stable flow (less than 420), transitional flow (between 420 and 780), and turbulent flow (greater than 780) at the start of which the phase angle decreases rapidly from about 34 degrees to 13 degrees, the friction coefficient increases rapidly, and the turbulent motion prevails over larger fractions of the flow cycle. The transitional and turbulent states are rich with nonaxisymmetric radial and vortical motions which burst themselves into existence most intensely during the later stages of the deceleration phase. 28 refs.
RightsThis publication is a work of the U.S. Government as defined in Title 17, United States Code, Section 101. Copyright protection is not available for this work in the United States.
Showing items related by title, author, creator and subject.
Kindelspire, David W. (1988-09);An experimental study was conducted to determine the effects of freestream turbulence on airfoil boundary layer behavior. Freestream turbulence intensity levels up to approximately 4% and length scales up to approximately ...
Study of transition phenomena in a straight channel with 40 to 1 aspect ration with and without imposed pulsations Part two: Reynolds number surveys Smith, Bradley Joseph (Monterey, California. Naval Postgraduate School, 1991-03);A channel with rectangular cross-section, 40 to 1 aspect ratio (height is0.0127 m) and 4.27 m test section length (336 channel lengths) is used to study the effects of imposed pulsations on laminar, transitional, and ...
Effects of 1, 2, 3 and 4 Hz imposed bulk flow oscillations on transition in a straight channel with 40 to 1 aspect ratio Koth, Howard Edwin (Monterey, California: Naval Postgraduate School, 1990-06);A channel with 40 to 1 aspect ratio and rectangular cross-section is used to study the effects of imposed oscillations on transition from laminar to turbulent flow. Oscillations are imposed using a single rotating vane ...