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Advances in Mechanical Engineering
Volume 2013 (2013), Article ID 921524, 8 pages
http://dx.doi.org/10.1155/2013/921524
Research Article

The Polymer Effect on Nonlinear Processes in Decaying Homogeneous Isotropic Turbulence

1School of Energy Science and Engineering, Harbin Institute of Technology, Harbin 150001, China
2School of Civil Engineering, Harbin Institute of Technology, Harbin 150090, China
3School of Municipal and Environmental Engineering, Harbin Institute of Technology, Harbin 150090, China

Received 9 October 2012; Revised 16 January 2013; Accepted 16 January 2013

Academic Editor: Tomoaki Kunugi

Copyright © 2013 Wei-Hua Cai et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

In order to study the polymer effect on the behavior of nonlinearities in decaying homogeneous isotropic turbulence (DHIT), direct numerical simulations were carried out for DHIT with and without polymers. We investigate the nonlinear processes, such as enstrophy production, strain production, polymer effect, the curvature of vortex line, and many others. The analysis results show that the nonlinear processes like enstrophy production (and many others) are strongly depressed in regions dominated by enstrophy as compared to those dominated by strain either in the Newtonian fluid case or in polymer solution case. Polymers only decrease the values of these parameters in the strongest enstrophy and strain regions. In addition, polymer additive has a negative effect on enstrophy and strain production, that is, depression of nonlinearity in DHIT with polymers.