Turbulent free jet simulations with LES and ILES based on NFT MPDATA

Numerical studies focusing on comparing the Large Eddy Simulations (LES) and Implicit Large Eddy Simulation (ILES) approaches in simulating the turbulent free jet are carried out in the presented work. In both approaches, the unstructured mesh-based Non-oscillatory Forward-in-Time (NFT) Multidimensional Positive Definite Advection Transport Algorithm (MPDATA) numerical scheme [1,2] was employed to integrate the incompressible Navier-Stokes equations. The capabilities of both the LES and ILES approaches to predict essential turbulent free jets are evaluated in the presented work, with LES carried out at Reynolds number Re = 1.1 × 104. Good agreement with the experimental data of Panchapakesan et al. 1993 [3] and Hussein et al. 1994 [4] was observed with both approaches. More impressively, energy spectra analysis revealed that ILES could also reproduce the -5/3 and -7 gradients that signify the universal inertia subrange and dissipation range for jets [5] respectively. The flexibility of the numerical scheme is also highlighted through numerical investigations with different mesh topologies.