It is well known that initial conditions significantly affect the flow field and the evolution characteristics of the jets. In the present study, experiments on twin pipe jets were performed to understand the effect of developing length on the twin-jet characteristics. The developing length was varied in the range of 4<L/D<9, and hot-wire data were acquired up to a downstream distance of 40D. Twin jets combine at farther downstream axial distance with an increase in the developing length due to delayed mixing brought about by relatively less intense vortex action. The range of the energy-containing eddies decreases, resulting in a decrease in the spread rates of the twin jet.
HussainA. K. M. F.ClarkR. A.Upstream influence on the near field of plane turbulent jets. Phys. Fluids, 1977, 20(9), 1416–1426.
2.
HussainA. K. M. F.ZedanM. F.Effects of the initial condition on the axisymmetric free shear layer: Effects of the initial momentum thickness. Phys. Fluids, 1977, 21(7), 1100–1112.
3.
NamerI.OtugenM. V.Velocity measurements in a plane turbulent air jet at moderate Reynolds numbers. Exp. Fluids, 1988, 6, 387–399.
4.
AntoniaR. A.XuG.Effect of different initial conditions on a turbulent round free jet. Expl Fluids, 2002, 33, 677–683.
5.
BurattiniP.AntoniaR. A.RajagopalanS.StephensM.Effect of initial conditions on the near field development of a round jet. Expl Fluids, 2004, 37, 56–64.
