Physics
Scientific paper
Jun 2005
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2005njph....7..142o&link_type=abstract
New Journal of Physics, Volume 7, Issue 1, pp. 142 (2005).
Physics
11
Scientific paper
We present an experimental test of Corrsin's conjecture against experimental data obtained by a particle tracking technique in approximately homogeneous and isotropic turbulent flow at Reynolds numbers Rλ ap 100. The conjecture states that \begin{equation*} R_L(t)\approx \int R_E(\bm{x},t)\,G(\bm{x},t)\,\rmd^3 x, \end{equation*}where RL(t - t') = langv(t)·v(t')rang is the Lagrangian velocity covariance function, G is the single particle mean Green's function, and RE(x - x', t - t') ≡ langu(x, t)·u(x', t')rang is the Eulerian two-point, two-time velocity covariance function. All terms in the relation have been measured in the experiment. The equation is exact if a conditional Lagrangian velocity function RL(t|x) is inserted in place of RE(x, t) on the right-hand side. RL(t|x) is obtained by restricting sampling of the two velocities to situations where both belong to the same fluid particle trajectory. The experimental data show that the RE(x, t) and RL(t|x) behave fundamentally differently, thereby seriously questioning the rationale of the conjecture. The estimate of RL(t), based on Corrsin's conjecture and the experimentally determined RE and G, is found to decrease too fast compared to the directly measured RL, thus underestimating the Lagrangian timescale by about 40%. Even asymptotically (t → ∞) the estimate is considerably lower than the measured Lagrangian correlation function. The simpler relation RL(t) = RE(0, t), which has also been attributed to Corrsin, appears to agree much better with data. Various simple physical models of the spatiotemporal Eulerian correlation function have been compared with data, and models inspired by eddy sweeping seem to perform well.
Mann Jakob
Ott Søren
No associations
LandOfFree
An experimental test of Corrsin's conjecture and some related ideas does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with An experimental test of Corrsin's conjecture and some related ideas, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and An experimental test of Corrsin's conjecture and some related ideas will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1164669