Computational Analysis of Subsonic Jets from Rectangular Nozzles with and Without Bevel

摘要

Numerical simulations of a turbulent compressible subsonic jet from baseline rectangular nozzles with aspect ratios of 2:1, 4:1, 8:1, as well as its beveled nozzles (both long and short), were carried out using a commercial computational fluid dynamics software. The Mach number at exit for the aforementioned nozzles was 0.9. Simulations were performed in a three-dimensional computational domain using steady Reynolds-averaged Navier-Stokes equations and a shear-stress transport k - omega turbulence model. The computational domain was discretized using a hexahedral/tetrahedral mesh with approximately 2.5 million cells. The flow was investigated for the velocity fields, as well as the mean and variance of the axial velocity. The impact of the aspect ratio and bevel length on these parameters was analyzed. The results were found to be in reasonable agreement with the available experimental data in the literature. It was observed that increasing the aspect ratio decreased the length of the potential core; thereby, a corresponding increase in turbulence and mixing was obtained. Again, beveling of the nozzle could significantly change both flow pattern and turbulence structures in the jet, which would make it an effective passive method for jet noise reduction.