TITLE:
The dynamic field in turbulent round jet discharging into a co-flowing stream
AUTHORS:
Mohamed Hichem Gazzah, Nejmiddin Boughattas, Hafedh Belmabrouk, Rachid Said
KEYWORDS:
Co-Flow; Turbulence; Jets; Models; Entrainment
JOURNAL NAME:
Natural Science,
Vol.2 No.6,
July
1,
2010
ABSTRACT: The effects of a co-flow on a spreading and entrainment rate of turbulent round jets have been studied numerically. The first and second order closure models are used and have been comp- ared with existing experimental data. The influence of theses models on the dynamic fields is examined. The results of the models in general agree well with the trends observed experiment- tally. The co-flowing imposed noticeable restri- ctions on the spreading and the turbulent mixing. Finally, an entrainment hypothesis has been introduced to describe the development of turbulent jets issuing into a stagnant or co-flowing air. It relates the mass flow rate of the surround- ing fluid entrained into the jet to the characteristic velocity difference between the jet and the co-flow. It is obvious that the co-flow decreases considerably the entrainment of air.