Journal of Fluid Mechanics


Hydraulic jumps due to oblique impingement of circular liquid jets on a flat horizontal surface


a1 Department of Mechanical Engineering, Indian Institute of Technology, Kharagpur 721302, India


An obliquely inclined circular water jet, impinging on a flat horizontal surface, confers a series of hydraulic jump profiles, pertaining to different jet inclinations and jet velocities. These jump profiles are non-circular, and can be broadly grouped into two categories, based on the angle of jet inclination, φ, made with horizontal. Jumps corrosponding to the range (25° < φ≤ 90°) are observed to be bounded by smooth curves, whereas those corresponding to φ≤ 25° are characterized by distinct corners. The present work attempts to find a geometric and hydrodynamic characterization of the spatial patterns formed as a consequence of such non-circular hydraulic jump profiles. Flow-visualization experiments are conducted to depict the shape of demarcating boundaries between supercritical and subcritical flows, and the corresponding radial jump locations are obtained. Theoretical calculations are also executed to obtain the radial locations of the jumps with geometrically smooth profiles. Comparisons are subsequently made between the theoretical predictions and the experimental observations, and a good agreement between these two can be observed. Jumps with corners, however, turn out to be comprised of strikingly contrasting profiles, which can be attributed to the ‘jump–jet’ interaction and the ‘jump-jump’ interaction mechanisms. A phenomenological explanation is also provided, by drawing an analogy from the theory of shock-wave interactions.

(Received June 06 2005)

(Revised July 31 2006)


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