Showing papers in "Tsagi Science Journal in 2011"

Modeling of dielectric barrier discharge actuators at various gas pressures and estimation of their influence on shear flows

Abstract: Numerical research of the gas pressure influence on a conduction current in a dielectric barrier discharge (DBD), the average volumetric force acting on gas from the discharge, and the power of heat release in the discharge is carried out for aerodynamic applications. The calculations are implemented with use of the earlier proposed boundary problem about the DBD generation near a flat dielectric plate. This problem statement takes into account such factors as the finite thickness of the exposed electrode, finite rates of desorption and the recombination of charged particles on the dielectric surface, and the electric field induced by a superficial charge. Represented are the results of numerical modeling of the incompressible Poiseuille and Couette flows under the time-averaged transverse force impact of DBD actuators placed along the main flow. The possibility of significant influence of an additional transfer of the main flow momentum due to the cross-flow (induced by actuators) on the structure and the characteristics of the considered shear flows is demonstrated.

Steady and periodic regimes of laminar flow around the rotating cylinder

Abstract: A numerical study of the problem of laminar infinite flow of viscous incompressible fluid around a rotating circular cylinder at Reynolds number $ 50 \le {\rm Re} \le 500 $ and dimensionless rotation rate $ 0 \le \alpha \le 7 $ has been carried out. The parametric map of flow regimes has been constructed, where two zones of steady and two zones of periodic solutions are signed out. The dependencies of the drag and lift coefficients on the rotation rate for $ {\rm Re} = 200 $ are studied in detail. Convergence of the numerical solution to the known asymptotic solution at large $ \alpha $ is confirmed.