Structures of Shear free Turbulence Near A Wall

@article{citeulike:2988986, abstract = {The effect of a wall on shear-free turbulence at moderately high Reynolds numbers (Re\_lambda=280) is investigated experimentally under steady boundary conditions. The experiments are performed in a tank containing four symmetrically positioned active grids, and the data consists 2-D velocity distributions, measured using PIV, with spatial resolution that matches the Kolmogorov scale. The results show an increasing anisotropy with decreasing distance from the wall, as the wall-normal component of the Reynolds stress decreases, whereas the wall-parallel component remains almost unchanged. The dissipation rate peaks away from the wall, by about 10\% of the integral scale. The primary source term of turbulent kinetic energy and wall-normal stress near the wall is pressure diffusion. Inter-component energy transfer caused by the pressure strain enhances the anisotropy by depleting the wall-normal component in favor of the tangential component. The contributions of turbulent diffusion and production to the balance of energy and Reynolds stresses near the wall are smaller than the terms involving dissipation and pressure. However, far from the wall the production and triple correlation terms balance the dissipation terms. Energy, vorticity and dissipation spectra indicate that the elevated dissipation rate is caused by breakup of the large eddies, which dominate the turbulence far from the wall, into energetic small-scale structures. The resulting much shorter length and time scales enhance the dissipation rates.}, author = {Sheng, J. and Malkiel, E. and Katz, J. }, citeulike-article-id = {2988986}, journal = {APS Meeting Abstracts}, keywords = {shear\_free}, month = {November}, posted-at = {2008-07-11 17:05:06}, priority = {2}, title = {Structures of Shear free Turbulence Near A Wall}, url = {http://adsabs.harvard.edu/cgi-bin/nph-bib\_query?bibcode=2003APS..DFD.KC010S}, year = {2003} }

TY - JOUR ID - citeulike:2988986 L3 - citeulike-article-id:2988986 TI - Structures of Shear free Turbulence Near A Wall JF - APS Meeting Abstracts N2 - The effect of a wall on shear-free turbulence at moderately high Reynolds numbers (Re_lambda=280) is investigated experimentally under steady boundary conditions. The experiments are performed in a tank containing four symmetrically positioned active grids, and the data consists 2-D velocity distributions, measured using PIV, with spatial resolution that matches the Kolmogorov scale. The results show an increasing anisotropy with decreasing distance from the wall, as the wall-normal component of the Reynolds stress decreases, whereas the wall-parallel component remains almost unchanged. The dissipation rate peaks away from the wall, by about 10% of the integral scale. The primary source term of turbulent kinetic energy and wall-normal stress near the wall is pressure diffusion. Inter-component energy transfer caused by the pressure strain enhances the anisotropy by depleting the wall-normal component in favor of the tangential component. The contributions of turbulent diffusion and production to the balance of energy and Reynolds stresses near the wall are smaller than the terms involving dissipation and pressure. However, far from the wall the production and triple correlation terms balance the dissipation terms. Energy, vorticity and dissipation spectra indicate that the elevated dissipation rate is caused by breakup of the large eddies, which dominate the turbulence far from the wall, into energetic small-scale structures. The resulting much shorter length and time scales enhance the dissipation rates. KW - shear_free AU - Sheng, J AU - Malkiel, E AU - Katz, J PY - 2003/November// UR - http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=2003APS..DFD.KC010S ER -