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The steady incompressible Navier-Stokes equations in a 2D driven cavity are solved in primitive variables by means of the multigrid method. The pressure and the components of the velocity are discretized on staggered grids, a block-implicit relaxation technique is used to achieve a good convergence and a simplified FMG-FAS algorithm is proposed. Special(More)
This paper focuses on improving the stability as well as the approximation properties of Reduced Order Models (ROM) based on Proper Orthogonal Decomposition (POD). The ROM is obtained by seeking a solution belonging to the POD sub-space and that at the same time minimizes the Navier-Stokes residuals. We propose a modified ROM that directly incorporates the(More)
The aim of this work is to combine penalization and level-set methods to solve inverse or shape optimization problems on uniform cartesian meshes. Penalization is a method to impose boundary conditions avoiding the use of body-fitted grids, whereas level-sets allow a natural non-parametric description of the geometries to be optimized. In this way, the(More)
This report focuses on improving the stability as well as the approximation properties of Reduced Order Models (ROM) based on Proper Orthogonal Decomposition (POD). The ROM is obtained by seeking a solution belonging to the POD subspace and that at the same time minimizes the Navier-Stokes residuals. We propose a modified ROM that directly incorporates the(More)
SUMMARY A new artificial boundary condition for 2D subsonic flows governed by the compressible Navier–Stokes equations is derived. It is based on the hyperbolic part of the equations, according to the way of propagation of the characteristic waves. A reference flow as well as a convection velocity are used to properly discretize the terms corresponding to(More)
Experiments and direct numerical simulations reveal the coexistence of two cascades in two-dimensional grid turbulence. Several features of this flow such as the energy density and the scalar spectra are found to be consistent with well known theoretical predictions. The energy transfer function displays the expected up-scale energy transfers. The vorticity(More)
This book presents the fundamental principle of dynamics, fused together with the conservation of mass equation, which is written formally as the sum of an irrotational contribution and a solenoid contribution following a Hodge–Helmholtz decomposition. The gradient of the scalar potential is associated with pressure forces whereas the rotational of the(More)