Explicit and implicit large eddy simulations of free jets

The paper presents studies of a turbulent free jet focusing on the comparison of the efficiency and accuracy obtained using the Large Eddy Simulation (LES) and the Implicit Large Eddy Simulation (ILES) approaches. The solutions are obtained by solving the incompressible Navier-Stokes equations using an unstructured mesh-based Non-oscillatory-Forward-in-Time (NFT) integration framework [1, 2]. The integration builds upon the second-order-accurate high-resolution Multidimensional Positive Definite Advection Transport Algorithm (MPDATA). The capabilities to adequately capture essential turbulent free jet features in both the LES and ILES approaches are demonstrated in the presented work, with the LES simulations carried out at Reynolds number Re = 1.0×104 . Both approaches show good agreement when compared against experiments of Panchapakesan et al. [3] and Hussein et al. [4], with the ILES approach showing a better prediction of the near-field development of the jet. The flexibility of the numerical scheme is also highlighted through numerical investigations with different mesh topologies.