Hydraulic jumps and their interactions due to multiple impinging jets

Abstract

Impingement cooling is a mechanism of heat transfer by means of collision, and can be achieved when a fluid jet strikes a surface. Multiple impinging jets increases rates of heat transfer considerably in comparison with single impinging jet. If the colliding fluid is a liquid, the flow of the thin film often gives rise to the formation of a complicated fluid dynamic phenomenon of circular hydraulic jump. The interaction between the hydraulic jumps formed due to multiple impinging jets creates interesting hydraulic jump interaction patterns. Depending on the spacing between the jets, their configuration, and their relative strengths, different kinds of hydraulic jump interactions are possible, resulting in a variety of flow patterns such as ‘upwash’ formation due to two closely spaced impinging liquid jets. The present study experimentally elucidates the jump–jump interactions formed due to normal impingement of two, three, and four liquid jets simultaneously on a flat horizontal surface. In case of more than two impinging jets, multiple stagnation lines are formed and these stagnation lines interact with each other giving rise to interesting flow patterns.