Large Eddy Simulation of Flow over a Valve in a Simplified Cylinder Geometry
This study focuses on gaining a deeper understanding on the formation of turbulence and other in-cylinder flow structures caused by the intake jets during the intake stroke in internal combustion engines. This is important as the in-cylinder turbulence has a large effect on the mixing of fuel and oxidizer. A fine resolution large eddy simulation (LES) is carried out on an incompressible flow (Re is equivalent to 100,000) over a static valve (lift d = 7 mm) alongside with three other simulations using coarser meshes. The problem is studied in a simplified valve-cylinder geometry on which experimental data by Yasar et al., (2006) is available. The vortex cores, produced by the shear layer of the intake jets, are visualized using the λ₂ definition for vortex cores. The governing flow structures are identified and some features of the flow's mixing capabilities are observed. Additionally, the mixing is studied by releasing a passive scalar into to the flow.