AtReynolds numbers approaching those ofmicro air vehicles (both engineered and natural), the Eppler 387 airfoil (in common with many other smooth profiles) can have multiple lift and drag states at a single wing-incidence angle. Prestall hysteresis and abrupt switching between stable states result from sudden flow reattachment and the appearance of a large separation bubble. It is shown that co...

We present a systematic, multiscale, fully detailed numerical modeling for dynamics of fluid flow and ion transport covering Ohmic, limiting, and overlimiting current regimes in conductance of ion-selective membrane. By numerically solving the Poisson-Nernst-Planck-Navier-Stokes equations, it is demonstrated that the electroconvective instability, arising from the electric field acting upon the...

The unsteady Navier{Stokes equations ooer a large variety of instantaneous solutions even for rather simple boundary conditions once the relevant spatial and temporal scales of the problem at hand are adequately resolved. This is especially true for DNS (Direct Numerical Simulation) of laminar-turbulent transition, where an initially lam-inar ow, disturbed by some unsteady uctuations \breaks do...

Crossflow-induced laminar-turbulent transition and the initial stages of turbulence are investigated by means of spatial direct numerical simulations for the accelerating 3-D flat-plate boundary layer of the ”Querströmungsprinzipexperiment” of the DLR-Göttingen [1]. The complete 3-D incompressible Navier-Stokes equations are solved marching in time on the basis of a 4-order Runge-Kutta scheme. ...

The unsteady Navier Stokes equations o er a large variety of instantaneous solutions even for rather simple boundary conditions once the rel evant spatial and temporal scales of the problem at hand are adequately resolved This is especially true for DNS Direct Numerical Simulation of laminar turbulent transition where an initially lam inar ow disturbed by some unsteady uctuations breaks down in...

We show using diagramtic arguments that in some (but not all) cases, the temperature dependent part of the chiral vortical effect coefficient is independent of the coupling constant. An interpretation of this result in terms of quantization in the effective 3 dimensional Chern-Simons theory is also given. In the language of 3D, dimensionally reduced theory, the value of the chiral vortical coef...

A large-eddy simulation (LES) solver which combines an immersed-boundary technique with a curvilinear structured grid has been developed to study the temporal and spatial dynamics of an incompressible rotor tip-clearance flow. The overall objective of these simulations is to determine the underlying mechanisms for low-pressure fluctuations downstream of the rotor near the endwall. Salient featu...

Two high-speed stereo PIV (HS-SPIV) systems have been used for the characterization of pulsed and continuous jet actuators in the turbulent boundary layer (TBL) wind tunnel at ONERA Lille, an Eiffel type wind tunnel in suction mode with a low turbulence level. The test aimed at generating an aerodynamic database useful for the characterisation of (unsteady) vortical structures responsible for t...