Numerical investigation of the velocity and spreading characteristics of non-circular turbulent jets at different Reynolds numbers

Abstract

The flow field characteristics of non-circular turbulent jets are investigated numerically. A steady numerical simulation is conducted using the k–ε turbulence model in Ansys Fluent software. A hotwire anemometer is utilized to collect velocity data along the jet centerline for velocity validation. The jet exit Reynolds numbers vary from 200 to 5000, covering both laminar and turbulent regimes. The mean flow field characteristics, such as mean velocity, turbulent intensity, velocity decay, and half-jet spread width, are examined. The simulated results depict that mean velocity profile decay reveals a universal decay pattern, and the lateral velocity distribution shows a top-hat-like velocity profile in the near field. It significantly changed into peak-shaped and parabolic-shaped at a far downstream distance. The turbulent intensity profile reveals that shear layer growth begins near the jet exits, and entrainment becomes strong with the Reynold number. The potential core region increases with Reynolds numbers. The jet spread width shows a linear increment with the jet exit Reynolds number. The presented numerical results agree well with the measured experimental results and are consistent with published data.