Decay of turbulence behind three similar grids

[摘要] u’ and v’ decay measurements were made behind three similar girds.The u’ readings were corrected for wire length and the v’ readings were corrected for the sensitivity of the v’-meter to u’.These corrected values were plotted against x/M on logarithmic cross-section paper.The slope of these lines gave the exponent in the theoretical law for the decay of isotropic turbulence.A consistent deviation was found between the average u’ and v’ values.A suitable length correction applied to the v’ values would increase them somewhat, lessening the discrepancy, and giving a true comparison between the two components of the turbulent energy.From a comparison of the present u’ values behind the 1” grid with the u’ values measured with a free stream turbulence level 10 times as great as the present one, it is concluded that the change in initial turbulence has no appreciable effect on the u’ behind a grid.

[发布机构] University:California Institute of Technology;Department:Engineering and Applied Science

[关键词] Aeronautical Engineering