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Though CFD methods have become very popular and widespread tools in the early as well as more advanced automotive design stages, they are still not so common in the motorcycle industry branch. The present work aims at the development of a comprehensive simulation environment, based on the open-source finite volume toolbox OpenFOAM®, for the aerodynamic and thermal fluxes optimization of a full motorcycle-and-rider geometry. The paper is divided in two parts: in the first one, the OpenFOAM® code is evaluated for a cold flow aerodynamic analysis, using a slightly simplified version of the Aprilia RSV4 motorbike geometry; in the second one, a mixed reduced scale-full scale methodology is proposed for the simultaneous assessment of aerodynamic forces and heat transfer performances of the engine cooling system. Results have been compared against other well established commercial CFD packages and, where available, with experimental measurements.

3D calculations of homogeneous charge spark ignition engines were carried out using the KIVA III code. A modified wall function was introduced by an approximate solution of the one -dimensional simplified equations of energy and mass balance. The model takes into account the pressure unsteadiness and the mean rate of combustion in boundary layer. Moreover a modified turbulent conductivity law was proposed following the classical Prandtl approach. The predictions of heat transfer model were compared with the mean heat flows calculated by thermodynamic processing of pressure cycles in motored engines. Two engines with different geometry were used. Namely: a CFR engine running 900 rpm and an AVL engine, running at 2200 rpm. The results regarding heat transfer seem very encouraging. The combustion phase was simulated using a Fractal Flame Model (FFM) elsewhere describe. Simulations in firing conditions were compared with measurements carried out on a CFR engine and on an AVL engine.