The influence of impinging jets on hydraulic jumps

Abstract

Experiments were carried out in a horizontal channel with a free jump and jumps with jets introduced at various angles. Particles within the jumps were traced using a high-speed video camera and the images were processed using a computer to determine particle velocities within the jumps. A simple numerical model using Strip Integrals across the flow is used to predict the kinematic characteristics of such jumps. Numerical and experimental results agree satisfactorily. The results show that even a relatively small momentum flux of the impinging jet can profoundly influence the jump in terms of the velocities within the jump and its surface profile. Plunging breakers occurring on a beach as the wave breaks may also be represented as a hydraulic jump with a weak jet impinging at its toe. This study shows that the impinging jet can increase energy dissipation within a plunging breaker.

Flow patterns, sedimentation and deposit architecture under a hydraulic jump on a non‐eroding bed: defining hydraulic‐jump unit bars

“…, 2000; Liu et al. , 2004; Yüksel et al. , 2004) and at sharp negative steps such as at a headcut (Bennett & Casali, 2001; Alonso et al.…”

“…Although jet separation from the bed has been described in sites with positive lee-side ramps (McCorquodale & Khalifa, 1980;Mossa & Tolve, 1998;Balachandar et al, 2000;Liu et al, 2004;Yü ksel et al, 2004) and at sharp negative steps such as at a headcut (Bennett & Casali, 2001;Alonso et al, 2002), wall jets entering hydraulic jumps above flat surfaces have, until recently, been assumed to expand into the tailwater without any separation from the floor. Run 1 confirms that wall jets in hydraulic jumps do separate from a solid floor rather than simply diffuse into a parabolic tailwater (cf.…”

Aspects of super to subcritical flow transition without a jump

“…Since the late 1950s, investigations of hydraulic jumps have focused on the understanding and description of large-scale mean flow characteristics. Over the years, several studies have been conducted to extend the hydrodynamics of the hydraulic jump (Lennon and Hill, 2006;Liu et al, 2012;Long et al, 1991;McCorquodale and Khalifa, 1983;Misra et al, 2008;Mitchell, 2008;Omid et al, 2010Omid et al, , 2011Resch et al, 1976;Yüksel et al, 2004;Zhang et al, 2012). Khatsuria et al (1988) introduced a reference section 20h 2 from the toe of the jump (h 2 is the sequent depth of the jump) where the turbulence effect on normal flow has completely decayed.…”