Velocity fluctuations in a turbulent soap film: The third moment in two dimensions
نویسندگان
چکیده
Quasi-two-dimensional decaying turbulence is studied in a flowing soap film by measuring the moments of the probability density function P„dv(r)... for the longitudinal velocity differences dv(r) on a scale r. As in three-dimensional ~3-D! turbulence, P becomes non-Gaussian with decreasing r. The third moment S3(r)[^„dv(r)... & is small and negative at small scales, but becomes positive at larger scales. The exact calculation of S3(r) for 2-D homogeneous isotropic turbulence relates this change in sign to the development of the velocity correlation function as the turbulence decays. © 1999 American Institute of Physics. @S1070-6631~99!01905-4#
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