Academie des Sciences Paris Comptes Rendus Serie Sciences Mathematiques, Sep 1, 1990
The three-dimensional Navier-Stokes equations are numerically integrated by a spectral method. Us... more The three-dimensional Navier-Stokes equations are numerically integrated by a spectral method. Using the symmetries of the initial data, a resolution of 863-cubed and high Reynolds numbers (140) are obtained. Visualizations of the resulting turbulent flow show that the vorticity is spatially more concentrated than the energy dissipation. Consequently, the turbulent activity is strongly correlated with low-pressure zones. Measures of the
Academie des Sciences Paris Comptes Rendus Serie Sciences Mathematiques, Mar 1, 1982
A numerical model based on the three-dimensional Navier-Stokes equations is presented for the cas... more A numerical model based on the three-dimensional Navier-Stokes equations is presented for the case of an incompressible flow. Initial conditions defined by Taylor and Green are used, wherein behavior is modified as a function of the harmonics of the wave number. Six discrete symmetries are observed in the flow, three which are implicit in the concept of a cube of a side pi, where a vertical component appears in the presence of pressure. A pseudo spectral technique is employed with a second order time scheme, in order to take advantage of fast Fourier transformations in analyzing the nonlinear terms. An example is provided for a viscous flow, with Reynold numbers of 1600 and 3000. The presence of Taylor-Green vortices was found to cause overly large recovery in the latter case.
Preliminary results on the behavior of a forced pendulum chain modified in order to obtain a tuna... more Preliminary results on the behavior of a forced pendulum chain modified in order to obtain a tunable frequency gap in the dispersion relation are presented. The limit of vanishing frequency gap is considered. Discrepancy with previous results [Physica D 163 (2002) 127-149] are discussed.
Academie des Sciences Paris Comptes Rendus Serie Sciences Mathematiques, Sep 1, 1990
The three-dimensional Navier-Stokes equations are numerically integrated by a spectral method. Us... more The three-dimensional Navier-Stokes equations are numerically integrated by a spectral method. Using the symmetries of the initial data, a resolution of 863-cubed and high Reynolds numbers (140) are obtained. Visualizations of the resulting turbulent flow show that the vorticity is spatially more concentrated than the energy dissipation. Consequently, the turbulent activity is strongly correlated with low-pressure zones. Measures of the
Academie des Sciences Paris Comptes Rendus Serie Sciences Mathematiques, Mar 1, 1982
A numerical model based on the three-dimensional Navier-Stokes equations is presented for the cas... more A numerical model based on the three-dimensional Navier-Stokes equations is presented for the case of an incompressible flow. Initial conditions defined by Taylor and Green are used, wherein behavior is modified as a function of the harmonics of the wave number. Six discrete symmetries are observed in the flow, three which are implicit in the concept of a cube of a side pi, where a vertical component appears in the presence of pressure. A pseudo spectral technique is employed with a second order time scheme, in order to take advantage of fast Fourier transformations in analyzing the nonlinear terms. An example is provided for a viscous flow, with Reynold numbers of 1600 and 3000. The presence of Taylor-Green vortices was found to cause overly large recovery in the latter case.
Preliminary results on the behavior of a forced pendulum chain modified in order to obtain a tuna... more Preliminary results on the behavior of a forced pendulum chain modified in order to obtain a tunable frequency gap in the dispersion relation are presented. The limit of vanishing frequency gap is considered. Discrepancy with previous results [Physica D 163 (2002) 127-149] are discussed.
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