Turbulence anisotropy characterization in an IC engine intake flow: a scale-resolved modeling study*

The intake flow of an internal-combustion engine, the so-called 'Flowbench' configuration, is computationally investigated using a transient modeling strategy that focuses on a RANS-based, eddy-resolving formulation referred to as Instability-Sensitive Reynolds Stress Model - IS-RSM (RANS - Reynolds-averaged Navier-Stokes), Jakirlic and Maduta (2015, Int J Heat Fluid Flow 51). The model provides the solution for all components of the corresponding residual stress tensor. The turbulence-resolving capability of this subscale stress model is enabled by an additional production of the length-scale-determining quantity in accordance with the SAS-proposal (SAS - Scale-adaptive Simulation), Menter and Egorov (2010, Flow Turbulence and Combustion 85). The results obtained on relatively coarser grids are discussed along with an appropriately resolved LES (Large-eddy Simulation), performed in parallel, and the experimental reference provided by Freudenhammer et al. (2014, Experiments in Fluids 55). The comparative results assessment illustrates correctly predicted instantaneous character of the intake flow as well as its assemble-averaged pattern, highlighting the Reynolds-stress anisotropy characterization revealing differently structured flow regions within the 'Flowbench' configuration.