Numerical Modeling Requirements for Coaxial and Chevron Nozzle Flows

None of the standard turbulence models usually found in CFD codes will accurately predict the mixing in even simple axisymmetric jets, and none of the turbulence model modifications that have been proposed to resolve this problem are accurate for more complex jet flows. Because of this, the turbulence modeling requirements for coaxial and chevron nozzle flows are not well understood at present. In this paper, a simple zonal model is used to identify these turbulence modeling requirements. In the course of this work, it was discovered that coaxial jet flows could be very unstable, leading to strongly asymmetrical jet development for small distortions of nominally axisymmetric geometries.

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