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This study presents a numerical study concerning flow control by suction and injection. The case studied is the flow field over a subsonic airfoil with four suction and injection slots on the suction side of the airfoil. Five different angles of attack, 0, 5, 10, 13.3 and 20 with the Mach number of 0.15 are studied. Three cases are studied in each angle of attack. The three cases are airfoil with surface suction, surface injection and the base airfoil. A commercial CFD code, the FLUENT, is used in this study. The effect of suction and injection on aerodynamic coefficients is investigated. The results show that the surface suction can significantly increase the lift coefficient. The injection decreases the skin friction.

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A large-scale, high-resolution finite element methodology for thermomechanical analysis of complex engine components has been developed. This paper describes the process and presents an example evaluation of an engine cylinder head. Because of its non-symmetric configuration, the cylinder head was entirely modelled. The geometric nature of the cylinder head requires very precise three-dimensional analysis techniques. The geometry modelling was carried out using a computer-aided engineering tool. Full multidimensional mechanical and thermal stress analysis in the cylinder head is made by using a finite element analysis commercial code. Validation of the simulation is achieved by comparison between simulation and experimental test results. The results of this analysis show high stresses at the valve bridge. These stresses result from a constrained thermal expansion of the cylinder head, and are generally compressive and radial in nature. Finite element analysis (FEA) and computational fluid dynamics (CFD) used in conjunction with experimental verification were found to be very powerful analysis tools for engine component development and design.