Experimental and numerical study of a turbulent free square jet

Abstract

Results of an experimental and numerical study of a turbulent free jet of air from a sharp-edged square slot are presented. The jet was treated as elliptic in the numerical study that predicted mean streamwise velocity, mean static pressure, and turbulence kinetic energy distributions. The experimental results include the mean velocity, the turbulent normal and shearing stresses obtained with hot-wire anemometry, and the mean static pressure acquired with a pitot-static tube in conjunction with a pressure transducer. The experimental results reveal the existence of pronounced mean streamwise velocity off-center peaks in the very near field, where positive mean static pressures were also found. Furthermore, the square jet is found to spread significantly faster in the near flow field than a jet from a round slot that has the same exit area as the square slot under identical test conditions. The general agreement between experimental results and numerical predictions is relatively good.

Numerical Simulation of Air-water Bubbly Jet Issuing from a Square Nozzle by a Vortex in Cell Method

“…The present result is slightly larger than the measured one by Tsuchiya et al [25] and the experimental formula of Quinn and Militzer [26]. The change in the axial direction is favorably computed.…”

Aerodynamic Simulation of Low Mach Turbulent Jets with Lattice Boltzmann Models

“…Slow decrease of the centerline velocity would indicate deeper penetration of the jet into the ambiance. Figure 5 showed the computed mean streamwise veloc- ity evolution on the jet centerline along with the experimental result of Quinn and Militzer [12]. The centerline velocity U ax is normalized with U max which is the maximum mean streamwise velocity along the jet center line.…”

“…The turbulent square jet has been studied experimentally and numerically [12]. The mean streamwise velocity at the center of the slot exit 0 U is 60 (m/s).…”

“…Starting from the prescribed initial conditions, the results are computed for a long enough time to allow for the establishment of statistically stationary turbulent field. The rate of decrease of the centerline velocity U ax of the jet can be used to make known the extent of penetration [12]. Slow decrease of the centerline velocity would indicate deeper penetration of the jet into the ambiance.…”

Real-Time Adaptive Control of Mixing in a Plane Shear Layer

“…A noncircular geometry was chosen because of its importance to technological applications in combustion (e.g., Gutmark, Schadow, Parr, Hanson-Parr & Wilson 1989b). The interest in noncircular jets for mixing and combustion applications stems from the fact that these jets typically entrain more ambient fluid than round jets having the same exit area and linear momentum flux [e.g., elliptic jets (Ho & Gutmark 1987) and square jets (Quinn & Militzer 1988)]. Furthermore, the presence of sharp comers in the nozzles of reacting jets leads to the appearance of azimuthal concentrations of small-scale motions within the ensuing vortical structures, with considerable enhancement of mixing and reaction of the chemical species (Gutmark et al 1989b).…”