Reynolds Number Effect on Flow Pattern of Turbulent Offset Jet in Narrow Chamber

The offset jet issuing into a narrow chamber was investigated by using the standard k-ε model with the volume-of-fluid (VOF) method. The commercially available CFD software ANSYS FLUENT version 15 was used for the purpose. In this study, the offset ratio, expansion ratio, and submergence ratio are fixed, the initial bulk velocity of the jet was varied from 2 ~ 6 m/s to change the Reynolds number. It is demonstrated that the flow pattern strongly dependent on Reynolds number. The surface attaching flow will be formed when the Re< 4×10⁵, and floor attaching flow will form when Re ≥ 4×10⁵, it follows that the critical Reynolds number should occur at Re_cr=4×10⁵. Attention is given that two big vertical vortexes can be found in surface attaching jet, and single big vertical vortex above the jet in floor attaching jet.

Keywords: offset jet; critical Reynolds number; flow pattern.