Affiliations: School of Mechanical Engineering, Pusan National
University, Pusan, 609-735, Korea
Abstract: The instantaneous and ensemble averaged flow characteristics of a
round jet issuing normally into a crossflow was studied using a flow
visualization technique and Particle Image Velocimetry measurements.
Experiments were performed at a jet-to-crossflow velocity ratio, 3.3 and two
Reynolds numbers, 1,050 and 2,100, based on crossflow velocity and jet
diameter. Instantaneous laser tomographic images of the vertical center plane
of the crossflow jet show that there exists very different natures in the flow
structures of the near field jet due to Reynolds number effect even though the
velocity ratio is same. It is found that the shear layer becomes much thicker
when the Reynolds number is 2,100 because of the strong entrainment of the
inviscid fluid by turbulent interaction between the jet and crossflow. The mean
and second order statistics are calculated by ensemble averaging over 1,000
realizations of instantaneous velocity fields. The detail characteristics of
mean flow field, streamwise and vertical rms velocity fluctuations, and
Reynolds shear stress distributions are presented. The new PIV results are
compared with those from previous experimental and LES studies.
Keywords: crossflow jet, particle image velocimetry, Reynolds number dependency, flow and turbulence characteristics