I. Introduction

    The aim of this report is to study an example of transient dynamic mesh with STAR-CD. The physical problem we studied is a simplified port-valve and piston-cylinder problem. This case is two-dimensional and represents a simplified four strocke engine.The domain is composed by the cylinder, the piston surface, the exhaust and intake valves and the exhaust and intake port. The fluid within the cylinder is assumed to be air, initially at room temperature and pressure.
    The simulation begins with the piston in bottom dead centre (BDC) position and finishes after a 3600  crank revolution. The flow is assumed to be turbulent and it's driven by the motion of the piston. The port boundary pressures are held constant throughout the simulation.