Experimental investigation of a swirling, axisymmetric, turbulent boundary layer with pressure gradient
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Hebbar, S. K.↗
Engineering topics
Hebbar, S. K.
Publications and source records attributed to Hebbar, S. K..
A three-dimensional turbulent boundary layer undergoing transverse strain and streamwise pressure gradient
Results from an experimental investigation designed to provide data on both mean and turbulence quantities in the axisymmetric, swirling boundary layer (with and without pressure gradient) flowing over a stationary cylinder downstreams of a spinning cylindrical section are presented. The pressure gradient was introduced into the flow field by a 25.4 mm-high, forward-facing, circular step mounted on the stationary cylinder, the step height being nearly equal to the thickness of the approaching boundary layer. All the measurements were made at a nominal upstream reference Reynolds number of 2.4 x 10 to the 6th power/m (corresponding to an upstream reference velocity of 36 to 37 m/sec) with the rotation of the spinner set to make its peripheral speed equal the reference velocity. The data reported included measurements of surface pressure and the mean surface shear-stress vector taken with a miniature, directional, surface-fence gage. These measurements were supplemented by oil-flow visualization studies of the stationary cylinder. The data indicates that the streamwise pressure gradient controls the development of the streamwise component of wall shear, but leaves the peripheral component of wall shear practically unaffected.
Hebbar, S. K.↗
Experimental study of a three-dimensional, shear-driven, turbulent boundary layer using a three-dimensional laser Doppler velocimeter
Experimental data have been obtained in a three-dimensional, shear-driven, turbulent boundary layer subjected to sudden transverse strain. Measurements made with a newly developed, three-dimensional laser Doppler velocimeter include all components of mean flow, turbulent Reynolds stresses, and triple-product correlations. Eddy viscosities, production, convection, turbulent diffusion, and dissipation (balance of kinetic energy equation) are extracted from the data. It was shown experimentally that eddy viscosity is strongly direction-dependent (not a scalar), indicating a need for full Reynolds stress modeling. Turbulence models for eddy viscosity, stress diffusion, pressure rate-of-strain, and anisotropy of Reynolds stresses are tested using the data. Calculations using a Reynolds stress equation model are compared with the data.
Driver, D. M.↗
An experimental investigation of a swirling, axisymmetric, turbulent boundary layer with pressure gradient
The results of an experimental investigation designed to document data on both mean and turbulence quantities in the axisymmetric, swirling boundary layer (with and without a pressure gradient) flowing over a stationary cylinder downstream of a spinning cylindrical section are discussed. The pressure gradient was introduced into the flow field by a 25.4-mm-high, forward-facing circular step mounted on the stationary cylinder, the step height being nearly equal to the approaching boundary-layer thickness. All the measurements were made at upstream reference velocity of 36-37 m/sec, with the rotation of the spinner set to make its peripheral speed equal to the reference velocity. The data reported include measurements of surface pressure and the mean surface-shear-stress vector (using a miniature directional surface-fence gage) and oil-flow visualization studies of the stationary cylinder. The data indicate that the streamwise pressure gradient controls the development of the streamwise component of wall shear but leaves the peripheral component of wall shear practically unaffected.
Hebbar, S. K.↗