Emmanuel Leriche

Direct numerical simulation of the flow in a lid-driven cubical cavity

Direct numerical simulation of the flow in a lid-driven cubical cavity has been carried out at a Reynolds number above 10 000. Both transient and steady-in-the-mean states of the flow posses long time scales requiring long integration times. A large fraction of the total kinetic energy and dissipation is concentrated in the near-lid mean flow. The flow over most of the domain is laminar with distinct wall-jet profiles found in three of the walls. The high momentum fluid near the lid transmits its energy into a downflowing nonparallel wall jet which separates ahead of the bottom wall. From the collision of this separated layer against the bottom wall two wall jets emerge. In this process the energy lost to turbulence by the impingement is partly recovered by the emerging wall jets.

Large-eddy simulation of the flow in a lid-driven cubical cavity

Large-eddy simulations of the turbulent flow in a lid-driven cubical cavity have been carried out at a Reynolds number of 12000 using spectral element methods. Two distinct subgrid-scales models, namely a dynamic Smagorinsky model and a dynamic mixed model, have been both implemented and used to perform long-lasting simulations required by the relevant time scales of the flow. All filtering levels make use of explicit filters applied in the physical space (on an element-by-element approach) and spectral (modal) spaces. The two subgrid-scales models are validated and compared to available experimental and numerical reference results, showing very good agreement. Specific features of lid-driven cavity flow in the turbulent regime, such as inhomogeneity of turbulence, turbulence production near the downstream corner eddy, small-scales localization and helical properties are investigated and discussed in the large-eddy simulation framework. Time histories of quantities such as the total energy, total turbulen...

High-Order Direct Stokes Solvers with or Without Temporal Splitting: Numerical Investigations of Their Comparative Properties

A recently proposed direct Stokes solver which decouples the velocity and pressure operators without calling for a temporal scheme is numerically analyzed, in comparison, first with the splitting scheme proposed by G. Karniadakis, M. Israeli, and S. Orszag in [ J. Comput. Phys., 97 (1991), pp. 414--443], and with the unique grid (

Large-Eddy Simulation of the Lid-Driven Cubic Cavity Flow by the Spectral Element Method

{\Bbb{P}}_{N}, {\Bbb{P}}_{N-2}

A coupled approximate deconvolution and dynamic mixed scale model for large-eddy simulation

) Uzawa approach for the space accuracy and computational costs. The Chebyshev collocation approximation is used to analyze the spectra of the continuous temporal evolution operators, and their discrete time versions, from the first to the fourth order. An explicit boundary condition is also involved in the proposed Stokes solver, and it is numerically shown that the trace of

Fundamental Stokes eigenmodes in the square: which expansion is more accurate, Chebyshev or Reid-Harris ?

{\bf \Delta }{ \bf u}

Mechanical action of the blood onto atheromatous plaques: influence of the stenosis shape and morphology

on the boundary must be evaluated through its

Direct Numerical Simulation of Buoyancy Driven Turbulence inside a Cubic Cavity

-{\bf \nabla} \times {\bf \nabla} \times

Modelling of fluid–structure interactions in stenosed arteries: effect of plaque deformability

contribution only; otherwise the ellipticity is lost before proceeding to the time discretization. The explicit evaluation of the rotational boundary term does not prevent the first and second order in time schemes from being unconditionally stable, while the schemes built at the next two higher orders are limited by the usual explicit (

Preconditioned Uzawa Algorithm for the Velocity-Pressure-Stress Formulation of Viscoelastic Flow Problems

{\cal {O}}(N^{-4})