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Prasad Perlekar
| Speaker: |
Prasad Perlekar (Dept. of Physics, Indian Institute of
Science, Bangalore, India)
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| Date: |
Thursday February 26, 2009
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| Title: |
Statistically
steady turbulence in Soap Films: Direct Numerical Simulations
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Abstract
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We
present a detailed direct numerical simulation (DNS) of statistically
steady two- dimensional turbulence in soap films. To mimic the
experiments of Ref.[1] we (a) use no-slip conditions on the boundaries,
(b) introduce air drag via an Ekman-friction term, and
(c) use Kolmogorov forcing. Our results are in very good agreement with
experiments. In particular, we find (a) the energy dissipation rates
because of the Ekman friction and conventional viscosity are comparable
and (b) topological properties of our DNS flows are similar to those in
experiments [2].
We also show that an SO(2) decomposition of velocity and vorticity
structure functions leads to multiscaling ratios (extracted via the
extended-self-similarity procedure), we find that velocity structure
functions display simple scaling whereas their vorticity counterparts
show multiscaling.
[1] M. Rivera, P. Vorobieff, and R.E.-Ecke, PRL, Vol. 81, pages =1417,
year = 1998.
[2] M. Rivera, X.L. Wu, and C. Yeung, PRL, Vol. 87, pages = 044501,
year = 2001.
[3] P. Perlekar and R. Pandit, arXiv:0811.1324
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