Entrainment Characteristics of Transient Turbulent Round, Radial and Wall-Impinging Jets: Theoretical Deductions

Abstract

Expressions for the mass entrained in transient turbulent radial and wall-impinging jets are derived by employing scaling laws derived for quasi-steady jets. Quantitative values of the mass entrained in these jets are compared with that in the round jet through an analytical study. In the case of the round jet, the expression has been derived and reported in the literature. It is shown that the ratio of mass entrained in transient radial and round jets for the same mass and momentum flow rates has a constant value with respect to time. In the case of the wall-impinging jet, it is shown that the ratio of the mass entrained in the jet to that in the round jet is a function of the impinging distance and time. The increase in entrained mass with increase in jet penetration in the fully developed region is slower in the wall-impinging jet than in the round jet.