A three-dimensional shear-driven turbulent boundary layer over a flat plate generated
by moving a section of the wall in the transverse direction is studied using large-eddy simulations. The configuration is analogous to shear-driven boundary layer
experiments on spinning cylinders, except for the absence of curvature effects. The
data presented include the time-averaged mean flow, the Reynolds stresses and their
budgets, and instantaneous flow visualizations. The near-wall behaviour of the flow,
which was not accessible to previous experimental studies, is investigated in detail. The
transverse mean velocity profile develops like a Stokes layer, only weakly coupled to
the streamwise flow, and is self-similar when scaled with the transverse wall velocity,
Ws. The axial skin friction and the turbulent kinetic energy, K, are significantly
reduced after the imposition of the transverse shear, due to the disruption of the
streaky structures and of the outer-layer vortical structures. The turbulent kinetic
energy budget reveals that the decrease in production is responsible for the reduction
of K. The flow then adjusts to the perturbation, reaching a quasi-equilibrium three-dimensional collateral state. Following the cessation of the transverse motion, similar
phenomena take place again. The flow eventually relaxes back to a two-dimensional
equilibrium boundary layer.
This work discusses some ongoing efforts towards the simulation of supersonic transverse jet interactions using LES. The code numerics feature a higher-order scheme with a "resurrected" limiting approach by the Jameson's dissipation scheme for dealing with shocks and other discontinuities. The methodology involves generating a "realistic" turbulent boundary layer using the "recycling-rescaling" approach that leads up to the transverse jet. A series of numerical experiments with increasing complexity are preformed to validate this methodology before attempting the transverse jet. The main goal of the effort is to be able to understand the complex physics involved and eventually be able to predict pressure fluctuation levels in such flows.
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