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Measurement of terms and parameters in turbulent modelsExperimental measurements of the mean and turbulent velocity field in a water flow, turn-around-duct is documented. The small radius of curvature duct experiments were made over a range of Reynolds numbers (based on a duct height of 10 cm) from 70,000 to 500,000. For this particular channel, the flow is dominated by the inertia forces. Use of the local bulk velocity to non-dimensionalize the local velocity was found to limit Reynolds number effects to the regions very close to the wall. Only secondary effects on the flow field were observed when the inlet or exit boundary conditions were altered. The flow over the central two-thirds of the channel was two-dimensional. Mean tangetial and radial velocities, streamlines, pressure distributions, surface shear stress; tangential, radial and lateral turbulent velocities and the Reynolds turbulent shear values are tabulated in other reports. It is evident from the experimental study that a complex numerical modeling technique must be developed to predict the flow in the turn-around-duct. The model must be able to predict relaminarization along the inner-convex-wall. It must also allow for the major increase in turbulence produced by the outer-concave-wall.
Document ID
19900016955
Acquisition Source
Legacy CDMS
Document Type
Contractor Report (CR)
Authors
Sandborn, Virgil A. (Colorado State Univ. Fort Collins, CO, United States)
Date Acquired
September 6, 2013
Publication Date
June 1, 1989
Subject Category
Fluid Mechanics And Heat Transfer
Report/Patent Number
NASA-CR-183993
NAS 1.26:183993
Accession Number
90N26271
Funding Number(s)
CONTRACT_GRANT: NAS8-36354
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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