Unsteady behaviour of opposite impinging jets interaction in crossflow

Abstract

A mixing of fuel with air in jet engine is studied by analyzing unsteady turbulent flow in a simplified flow channel which consists of the opposed jets in a cross-flow. The mixing behaviors of the flow have been investigated parametrically by using a momentum flux ratio between jet and cross-flow to find that the mixing performance was related with the momentum flux ratio. It was also suggested that the mixing performance was connected with the flow behavior of the opposing jets in their interaction area. Presently the frequency analysis is performed to elucidate the characteristics of unsteady opposed jets in a cross-flow. The results show that the Kelvin-Helmholtz instability and low frequency fluctuation exist in the opposed impinging jets. The strength of the K-H instability is about one-tenth of the low frequency fluctuation. The low frequency fluctuation is related to the circulation which is caused from the collision between opposed jets.