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THE FREE SURFACE PROFILE OF HYDRAULIC JUMPS IN ABRUPTLY EXPANDING INCLINED CHANNELS

Congress: 2008
Author(s):
J. Demetriou Associate Professor (Rd) National Technical University of Athens, Hydraulics Laboratory 1 Iroon Polytechnion St., Zografou15780, Athens, Greece. Tel. 0030-9341007, e-mail:idimit@central.ntua.gr

Keyword(s): Surface profile, repelled hydraulic jumps
AbstractIntroduction and Objective: This laboratory research is concerning the free surface profile of a rather complex hydraulic jump, which is created beyond a sluice gate within a straight rectangular but non prismatic inclined channel (angle φ with 0o≤φ≤8o). The channel is abruptly expanding at the sluice gate location and the created flow separation is dominant, fully affecting these profiles. The profiles are also compared to corresponding jump profiles in prismatic inclined channels. Method: With x=inclined distances from the beginning of the jump and h= corresponding water depth (perpendicular to the channel floor), b0/b1= upstream to downstream width ratio (0.5≤bo/b1≤0.85), Lh=jump length and h1, h2, water depths at x=0 and x=Lh correspondingly, the flow profiles are elaborated in terms of dimensionless depths vs dimensionaless distances f and bo/b1, where f= suitable function which is determined from the experiments (measurements of x and respective h, h1, h2, bo, b1, φ, Lh). Results and Conclusions: All profiles were elaborated with the above method, they are fully systematic for all angles φ and bo/b1 and show that: (i) For h=h1, while for h=h2, where the profiles are continuously ascending. (ii) All profiles are at lower level than corresponding profiles in jumps within prismatic channel (bo/b1=1).
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