A Numerical and Experimental Investigation of a DISI-Engine Intake Port Generated Turbulent Flow

The CFD simulation of the turbulent flow induced by the intake port of a modern direct injection gasoline engine requires the application of advanced turbulence models taking into account the unsteady nature of the flow. The validation of such models necessitates the availability of high quality experimental data. The present paper describes a comparative analysis between Detached Eddy Simulation, a “standard” hybrid Large Eddy Simulation approach, and an innovative concept called Scale Adaptive Simulation. The flow field generated by the cylinder-head of a production four-valve gasoline engine in a configuration with fixed valve positions has been simulated. The same configuration has been investigated experimentally using a stereoscopic High-Speed Particle Image Velocimetry system. The main focus of the work has been put on the very high time-resolution of the measured data, as well as on the strong refinement of the numerical mesh employed. With an acquisition frequency of 20kHz and a mesh size of about 30 million cells, a particularly good resolution of the turbulence structures was achieved both in the experiment and the simulation. A new visualization method has been proposed to characterize and quantify the turbulent structures developing under the flow conditions considered.