SUMMARYIn this paper, a numerical investigation of incompressible flow around a hydrofoil is presented. The laminar flow was modeled at different angles of attack. Momentum and continuity equations were coupled by the artificial compressibility scheme. In finite-volume method, convective fluxes were calculated and compared by four schemes. Flux averaging with pressure correction was used. The other characteristic-based (CB) methods consisted of Roe scheme and original CB scheme. A revised CB scheme was implemented in this research, which demonstrated very accurate solutions with respect to others. The results confirmed the superiority of the revised upwind scheme regarding accuracy and convergence without any requirement to artificial viscosity. The problem was studied at high Reynolds numbers at the onset of turbulence. For time discretization, the fifth-order Runge-Kutta scheme was used. Results were compared with those of others in which good agreement was observed. Numerical experiments were performed on the NACA0012 hydrofoil.

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In this paper, a numerical investigation is carried out to realize the behavior of a fabricated vortex tube. A computational fluid dynamics model is used to simulate the flow field structure in the tube in order to study the effects of various parameters on the performance and temperature separation. Numerical results such as temperature separation versus cold outlet mass fraction are obtained for a specific vortex tube with given inlet thermo physical properties. The numerical results are obtained for various amounts of cold outlet mass fractions. The calculated temperature distributions inside the Ranque-Hilsch Vortex Tube (RHVT) are simultaneously compared with available experimental results and a good agreement between them is noticed. It is found that increasing the inlet nozzle height improves the performance of the RHVT. The results also indicated that small values of cold mass fraction give best result in cold exit temperature difference.