Interaction of a wall-jet with a shear flow

Mukherji, Sanjib K., author
Sadeh, Willy Z., author
Fluid Dynamics and Diffusion Laboratory, Fluid Mechanics Program, Department of Civil Engineering, Colorado State University, publisher
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An experimental investigation of a flow field resulting from the interaction between a spreading turbulent wall jet on a smooth surface and a shear flow was conducted. The combined flow was formed by a downward circular jet penetrating perpendicularly a moving shear stream confined within a constant-area open channel. A hot-wire survey of mean velocity and turbulence intensity was carried out. A similar variation of mean velocity was found to exist on either side of the axis of the impinging jet, provided that appropriate characteristic scales were used. Similarity was obtained by dividing the flow into an inner and an outer layer, and by subdividing the latter into two zones of equal thickness. This partition into three distinct regions was deduced from the velocity change with height and, particularly, from the existence of a local characteristic maximum velocity. Within each region, velocity and length scales were formulated. The former was defined in terms of the local maximum velocity for the inner layer. In the two zones of the outer layer the velocity scales were defined in terms of the zonal maximum excess velocities. The excess velocity was computed with respect to the local free-stream velocity characteristic to this flow. In all three regions, the thicknesses of the layers were utilized as the length scale. The similarity in mean velocity variation is corroborated by the computed constant values of the shape factor for each particular region of the flow. The use of analogous scales led to similarity in the change of mean energy. Furthermore, it was found that the turbulence intensity variation exhibited similarity when the same scales used for the velocity were employed.
March 1972.
Includes bibliographical references (pages 38-39).
Project THEMIS, technical report no. 15.
Prepared for Office of Naval Research. Contract No. N00014-68-A-0493-0001. Project No. NR 062-414/6-6-68(Code 438).
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Dynamic meteorology
Jet stream
Air flow -- Mathematical models
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