Abstract
In this paper, we report on a numerical study of the interaction and merging of a turbulent crossflow with an incoming turbulent jet in a T-junction with rectangular cross section. Our study is based on wall-resolved and experimentally validated large eddy simulations. The bulk Reynolds number of the crossflow is 15 000. Further, we consider cases with two different momentum ratios, namely, MR = 2 and MR = 0.5. In the presentation of the results, we elaborate on the main features of the flow, namely, the shear layers that emanate from the corners of the entry of the jet, the large recirculation bubble downstream the incoming jet, and the mixing process beyond the reattachment point. For validation purposes, we compare our simulations with existing experimental data. This comparison shows a good agreement between our numerical predictions and the measurements. First- and second-order statistics of the flow are also presented and analyzed in detail. Our simulations reveal two features of the flow that have not been reported before in studies of T-junctions. The first one is a secondary small-scale recirculation region between the entry of the jet and the large recirculation bubble. The second one is the negative turbulent kinetic energy production that occurs in the recirculation bubble and close to the reattachment of the flow. The analysis of our results further reveals that just across the entry of the jet, the boundary layer in the wall opposite to the jet experiences a favourable pressure gradient due to a Venturi effect induced by the incoming jet. In turn, this favourable pressure gradient contributes to the local relaminarization of the flow. On the other hand, the boundary layer downstream the recirculation bubble experiences an adverse pressure gradient. In both cases, a significant deviation from the universal law of the wall is confirmed.
Published Version
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call