The cylinder charge motion of a diesel engine at the time of injection influences to a significant degree the mixture formation and combustion and consequentially the resulting emissions. Experimental methods as well as computational fluid dynamics (CFD) can be used to investigate the occurring flow phenomena. The Large Eddy Simulation (LES) as a scale resolving turbulence model allows to resolve instantaneous and local flow structures as well as cyclic variations. LES is used in this thesis to simulate the in-cylinder flow of a realistic two-valve diesel engine. The LES results are validated using experimental data. In addition, the application of LES in an industrial environment is assessed, especially with regards to a systematic comparison to more established Reynolds-Averaged Navier-Stokes (RANS) methods. For validation purposes, a comprehensive experimental High-Speed PIV data basis composed of high-resolution – both in time and space – velocity vector fields is available. To ensure comparability of simulation results to experimental data, the simulation boundary conditions and geometry are defined to match the experimental engine investigations as closely as possible.

The simulation was carried out using the commercial CFD solver ANSYS CFX on a high performance computer cluster. A high quality block structured mesh consisting of hexahedral elements was used. As part of the present work, an algorithm for automated remesh based on mesh quality criteria was developed. This was necessary because of mesh deformation due to the moving parts withing the cosidered engine geometry. To reduce computational time for the simulation of several succesive engine cycles, which are necessary for statistical evaluations of mean flow fields, turbulence and cycle-to-cycle fluctuations, a cycle-parallel approach was used.

The inlet flow with very high velocities and fluctuations and the swirl flow which devolopes during the compression stroke are two main characteristic properties of the in-cylinder flow of the two-valve diesel engine. At the end of the compression stroke, the turbulence within the piston bowl increases due to the squish flow. The Large Eddy Simulation is able to reproduce these flow phenomena and the instantaneous and local fluctuations as well as the resulting turbulent kinetic energy, especially during the compression phase. Also cyclic variations, e.g. visible as cycle-to-cycle variations of the swirl center, are predicted in good agreement to experiment.

In principle, the application of LES for the simulation of in-cylinder flows in industrial contexts is possible. The desired reproduction of the small scale flow structures as well as the cycle-to-cycle variations is achieved by the LES. Average values are in good agreement to the experiment for both simulation methods – LES as well as RANS. However, in comparisson to RANS, the LES requires significantly more effort and resources for all three stages of the simulation, that are pre-processing, computation and post-processing.