Home Books eBooks Journals References & Proceedings Authors, Editors, Reviewers A-Z Product Index Awards
Turbulence and Shear Flow Phenomena -1 First International Symposium

ISBN:
1-56700-135-1 (Print)

ON THE EFFECTS OF VELOCITY PROFILES ON THE TOPOLOGICAL STRUCTURE OF A JET IN CROSS FLOW

Daniel T. H. New
Department of Mechanical and Production Engineering, National University of Singapore 10 Kent Ridge Crescent, Singapore 119260

T. T. Lim
Department of Mechanical and Production Engineering National University of Singapore 10 Kent Ridge Crescent, Singapore 119260

S. C. Luo
Department of Mechanical and Production Engineering, National University of Singapore 10 Kent Ridge Crescent, Singapore 119260

Abstract

The effect of jet exit velocity profile on the topological structure of a round jet in a cross flow is investigated experimentally using the laser induced fluorescence technique. The study is focused on two velocity profiles, namely top-hat and parabolic profiles. The jet Reynolds number considered ranges from 350 to 1750, with the corresponding velocity ratios varying from 1 to 5. The results show that the top-hat jets are more unstable and likely to shed shear layer vortices than parabolic jets. Interestingly, it is found that the parabolic jets penetrate higher into the flow, but the large- scale structures appear to be less coherent than those of the top-hat jets. These findings suggest that the characteristics of a jet in a cross flow is not only a function of the Reynolds number and the velocity ratio, but also a function of the shear layer thickness and hence velocity profile.