Acceleration statistics as measures of statistical persistence of streamlines in isotropic turbulence

• Published in: Physical review. E, Statistical, nonlinear, and soft matter physics Vol. 71; no. 1 Pt 2; p. 015301
• Main Authors: Goto, S, Osborne, D R, Vassilicos, J C, Haigh, J D
• Format: Journal Article
• Language: English
• Published: United States 01.01.2005
• ISSN: 1539-3755
• DOI: 10.1103/PhysRevE.71.015301

We introduce the velocity Vs of stagnation points as a means to characterize and measure statistical persistence of streamlines. Using theoretical arguments, direct numerical simulations (DNS), and kinematic simulations (KS) of three-dimensional isotropic turbulence for different ratios of inner to outer length scales L/eta of the self-similar range, we show that a frame exists where the average Vs = 0 , that the rms values of acceleration, turbulent fluid velocity, and Vs are related by La'/u'2 approximately (V's/u')(L/eta)(2/3+q) , and that V's/u' approximately (L/eta)q with q = -1/3 in Kolmogorov turbulence, q = -1/6 in current DNS, and q = 0 in our KS. The statistical persistence hypothesis is closely related to the Tennekes sweeping hypothesis.