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Numerical investigations on the flow control around airfoils, in conjunction with Coandã effect, based on RANS equations are done. The circulation control uses the tangential blowing jet on the upper surface of the airfoil near the trailing edge with the rounded or modified flatback surface. Flow field spectra around such a configurations, involving the delayed of flow separation are obtained and analyzed by CFD methods. Thus can be identified the optimum domain of the geometric and jet flow parameters in which this flow control method should be used. [ABSTRACT FROM AUTHOR]

Coanda effect consists of the tendency of a jet to adhere to and to flow around nearby solid boundaries. This general class of phenomena, which may be observed in both liquid and gaseous jets, are known as the Coanda effect. In this paper, interest in the detailed behavior of an existing Coandă ejector model is taken, used in propulsion systems. The goal is to investigate the influence of various geometric parameters and pressure ratios on the Coandă ejector performance. The application of the Coandă effect to the directional control of a jet is also presented. Deviation of the thrust force by direct flow can be achieved by using the Coanda effect to change the angle of the primary jet engine exhaust nozzle. Since single jet flows or multi-jet flows are extensively applied in conjunction with the Coandă surface, as confined or free jet flows, in the last part of the paper, further insight into complexities involving issues such as the variety of flow structure and the related bifurcation and flow instabilities are provided. Thus, the conditions and the limits within which one can benefit from the advantages of Coandă-type flows are determined. [ABSTRACT FROM AUTHOR]

A design method and analysis tool of an UAV propeller based on Blade Element Momentum Theory (BEMT) for low-Reynolds number flow is presented. BEMT is completed with 3D equilibrium- implementation, a post-stall model and swirl velocity considerations to improve the accuracy of the results. An open-source code, JBlade, based on BEMT is used to obtain performance curves in off-design cases for a given propeller. Finally, the results are analyzed for a UAV Hirrus propeller. This methodology can be used successfully in the preliminary design phase of an UAV propeller, whose data can then be used as input in an optimization method. [ABSTRACT FROM AUTHOR]

Combustion phenomenon is one of the most important problems involved in different industries, such as gas turbines, combustion chamber, melting of metals, etc. In this paper, combustion process of methane downstream of an axisymmetric sudden expansion in a circular pipe with a constant wall temperature has been studied. The conservation equations of mass, momentum, energy, and species as well as additional equations due to turbulence modeling have been numerically solved. The standard k-ε model and eddy dissipation combustion model has been used to simulate the turbulence and combustion phenomenon, respectively. Properties of gaseous mixture have been computed using the ideal gas equation of state. The governing equations have been discretized using a finite volume approach and power law scheme and the resulting set of algebraic equations has been solved simultaneously using the SIMPLER algorithm on a non-uniform staggered grid system. The numerical results have been compared with the other's numerical results and experimental data. [ABSTRACT FROM AUTHOR]