ORGANIZED EDDY SIMULATION APPROACH FOR TURBULENCE MODELING OF UNSTEADY AERODYNAMIC FLOWS

The present paper deals with the problem of efficient modeling of unsteady turbulent aerodynamic flows in high Reynolds number. The capabilities of higher-order closures implemented in the Organized Eddy Simulation(OES) approach are provided in the context of the solution of phase-averaged Navier-Stokes equations. The needs of reconsidering the turbulent scales coming from modeling of flows in statistical quilibrium, in the sense of the Kolmogorov theory are discussed for the present class of flows in non-equilibrium. Reconsideration of diffusivity scaling for the two-equation turbulence models in OES is achieved by means of the second-order-moment closures. The possibilities offered by the Direct Numerical Simulation (DNS) approaches, applied to aerodynamic flow configurations (flows around wings) are shown in respect to a thorough physical understanding of the flow unsteadiness for an improved flow physics modeling. Especially, the ability offered by the present DNS to quantify the phase-averaged turbulent stress tensor and the unsteady velocity gradients is discussed in respect to constitutive laws for urbulence, for the present class of unsteady aerodynamic flows. Furthermore, a special attention is addressed on compressibility effects of the transonic regime on the unsteadiness and onset of turbulence around wings.

کلیدواژه ها:

Turbulence Modeling-Unsteady Flows-Aerodynamics-Transition-DNS