Numerical investigation of coaxial jets entering into a hot environment

Coaxial jets with and without a supersonic core flow are typical for many technical applications and therefore of general interest. These jets show a lot of unsteady phenomena such as shear layer instability and transition to turbulence. Their accurate numerical simulation is still challenging despite todays available computing resources. The strategy of using high-fidelity numerical methods and a high spatial resolution helps to increase the range of resolved scales of the flow. This paper focuses on the numerical simulation of coaxial jets entering into a hot environment. Based on these results a new correlation model and optimisation criteria is proposed to predict the potential core- and supersonic length of the coaxial jet and leading to a significantly increased jet length. In particular, the enlarged supersonic jet length is of interest for special industrial applications.