Measurements of prandtl number of an elliptic jet

Abstract

The turbulent Prandtl number, Prt, distributions of a heated contoured contraction nozzle elliptic air jet with a 2:1 aspect ratio issuing into stagnant, unconfined surroundings were presented. The measurements were carried out with X-wire and three-wire (a cold wire in front of an X-wire) probes. The normalized RMS velocities in both lateral and span-wise directions were consistently smaller than those in the streamwise direction, indicating the anisotropy of the turbulence in the flow. The Prt evaluated based on the self-preserved data of Reynolds shear stress, uv, and heat flux, vθ, at x = 30De decrease sharply from the center and only remained at a constant value of about 0.8 within the range of 0.4 ≤ y ̸Ly ≤ 1.8 along the major axis while a gradual increase is observed in the minor axis. A constant Prt in both axes should not be granted in the computational modeling and analysis of a heated elliptic jet.