Turbulent jet characteristics for axisymmetric and serrated nozzles

• Turbulent jet characteristics are explored for an axisymmetic and serrated nozzle.
• Numerical solutions are performed on grids from 7 M to 20 M nodes.
• Validation against a variety of experimental data is made for the round jet.
• Comparisons of round and chevron jet are made in terms of mean velocities and higher order turbulent statistics.
• A user-level scheduling procedure is found to enhance the scalability of the parallel flow solver.

Turbulent jet large eddy simulations (LES) are performed at Mach 0.9 and Reynolds number around 106106. Implicit large-eddy simulation (ILES) is employed, namely omitting explicit subgrid scale models. The Reynolds-averaged Navier–Stokes (RANS) solution is blended into the near wall region. This makes an overall hybrid LES-RANS approach. A Hamilton–Jacobi equation is applied to remove the disparate turbulence length scales implied by hybridization. Computations are contrasted for a baseline axisymmetric (round) nozzle and a serrated (or chevron) nozzle with high bending and penetration. Jet characteristics for both nozzles are studied in detail with well documented experimental data compared. The chevron effects are demonstrated by comparing both solutions using the same mesh resolution and flow conditions. Higher order velocity moments with potential for aeroacoustic modeling and noise prediction, such as the two-point velocity spatial correlations, are also explored. Numerical simulations presented in this study utilize an in-house flow solver with improved parallel scalability and efficiency by means of data packeting and a scheduling algorithm similar to the Round Robin scheduling.