Scalings and structures in turbulent Couette-Taylor flow - art. no. 016308

The scaling of velocity structure functions in Couette-TayIor flow [Lewis a nd Swinney, Phys. Rev. E 59; 5457 (1999)] is revisited to obtain more accur ate values of the scaring exponents for the Reynolds number range investiga ted, 12 000 to 540 000 (Taylor Reynolds numbers, 34<R-<lambda><220). System atic convergence of the statistics with increasing sample size is examined, and the uncertainty of the scaling exponents is assessed. At all Reynolds numbers the data support the hierarchical symmetry proposed by She and Leve que [Phys. Rev. Lett. 72, 336 (1994)]. The She-Leveque constant <beta> has a value of 0.83, indicating greater intermittency in Couette-TayIor turbule nce than in free jets, where beta = 0.87. The constant gamma, which is a me asure of the degree of singularity of the most intermittent structure, decr eases-from 0.14 far R<10(5) to 0.10 for R> 10(5); this transition correspon ds to a visually observed break up of the Taylor vortex roll structure with increasing R.