Michael W. Plesniak

Evolution of jets emanating from short holes into crossflow

The evolution of a short injection-hole jet issuing into a crossflow at low blowing ratios is presented. Particle image velocimetry (PIV) is used to determine structural features of the jet/crossflow interaction throughout its development from within the jet supply channel (which feeds the holes), through the injection hole, and into the crossflow. The effect of supply channel feed orientations, i.e. counter to, or in the same direction as the crossflow is emphasized. Feed orientation profoundly affects such jet characteristics as trajectory and lateral spreading, as well as its structural features. Fluid within the high-speed supply channel exhibits swirling motions similar to the flow induced by a pair of counter-rotating vortices. The sense of rotation of the swirling fluid depends upon the orientation of the supply channel flow with respect to the crossflow, and in turn impacts the in-hole velocity fields. In the coflow supply channel geometry (channel flow is in the same direction as the free stream), a pair of vortices exists within the hole with the same sense of rotation as the primary jet counter-rotating vortex pair (CRVP)

Scalar mixing in a confined rectangular jet in crossflow

An experimental investigation of a confined rectangular jet in crossflow was performed. The rectangular jet is highly confined in that it spans almost 80% of the crossflow duct, rather than issuing into a semi-infinite crossflow. Furthermore, the jet is confined in the cross-stream direction because it issues into a relatively narrow duct. In addition, the flow rate of the secondary jet is large (up to 50% of the crossflow flow rate) which also influences the jet–crossflow interaction. Configurations of this type are found in a variety of different industrial manufacturing processes used to mix product streams. A systematic variation of three pertinent parameters, i.e. momentum ratio, injection angle and development length, was performed. A full factorial experiment was run using three velocity ratios (

The occurrence of the Coanda effect in pulsatile flow through static models of the human vocal folds

Vr\,{=}\,0.5, 1.0, 1.5

The influence of large-scale, high-intensity turbulence on vane aerodynamic losses, wake growth, and the exit turbulence parameters

), three downstream distances (

Film Cooling Effectiveness for Short Film Cooling Holes Fed by a Narrow Plenum

x/D_{h}\,{=}\,6, 10, 19

A synergistic approach to the design, fabrication and evaluation of 3D printed micro and nano featured scaffolds for vascularized bone tissue repair.

) and six injection angles (

Non-Uniform Flow Behavior in a Parallel Plate Flow Chamber Alters Endothelial Cell Responses

\alpha\,{=}\,18^\circ, 24^\circ

Curved two-stream turbulent mixing layers: three-dimensional structure and streamwise evolution

, 30^\circ, 48^\circ, 60^\circ, 90^\circ

The influence of inlet velocity profile and secondary flow on pulsatile flow in a model artery with stenosis

). A planar Mie scattering mixing diagnostic system was used to evaluate the relative mixing effectiveness at various conditions within the parameter space studied. Three regimes for the jet–crossflow interaction and the resulting scalar concentration field were revealed: ‘wall jet’, ‘fully lifted jet’ and ‘reattached jet’. To understand the flow physics in these regimes, a more detailed exploration of the secondary flow and coherent structures was required. This was accomplished by acquiring velocity field data at measurement locations and conditions that demarcate the different regimes (

Spanwise averaging of plane mixing layer properties

\alpha\,{=}\,30^{\circ}