Turbulent mixing

We present a generalisation of the Kármán–Howarth–Monin (K–H–M) equation to include variable-density (VD) effects. The derived equation (i) reduces to the original K–H–M equation when density is a constant and (ii) leads to a VD analogue of the 4/5-law with the same value of constant (=4/5) appearing as the prefactor of the dissipation rate.

This paper reports results of a comprehensive experimental investigation of inclined round dense jets in an otherwise stagnant fluid. The tracer concentration field is measured for six jet discharge angles $\\theta\_{0} = (15^o, 30^o, 38^o, 45^o, 52^o, \\& 60^o) $ and jet densimetric Froude number of $F\_{r}$ = 10 – 40 using the planar laser-induced fluorescence (LIF) technique; selected jet velocity measurements are made using Particle Image Velocimetry (PIV).