A Moving Mesh Strategy to Perform Adaptive Large Eddy Simulation of IC Engines in OpenFOAM®

The paper focuses on a mesh moving method based on non-conformal topologically changing grids for Adaptive Large Eddy Simulation of IC engines in OpenFOAM®. With respect to authors’ previous work, a more efficient algorithm to handle the connectivity of non-conformal interfaces and a mesh-motion solver supporting multiple layer addition/removal of cells, to decouple the timestep constraints of the mesh motion and of the fluid dynamics, have been developed. Other new features include automatic decomposition of large multiple region domains to preserve processors load balance with topological changes and additional tools for automatic parallel preand post-proccessing. Finally, a transient solver for compressible flow of Newtonian fluids using a merged PISO-SIMPLE algorithm has been extended to work with the proposed mesh motion. The resulting framework allows to perform simulations with moving grids where initial mesh properties (skewness and non-orthogonality) are preserved during the engine cycle, favoring an improved accuracy of the fluid-dynamic solution and a fast convergence of the fluid dynamic solver. Also, when LES simulation is performed, the filter width results to be constant during the all simulation. The paper describes the new developments by the authors and includes some validation tests on full-cycle simulation of a single cylinder engine with Transparent Combustion Chamber (TCC) under motored conditions.