中国物理B ›› 2012, Vol. 21 ›› Issue (11): 114701-114701.doi: 10.1088/1674-1056/21/11/114701

• ELECTROMAGNETISM, OPTICS, ACOUSTICS, HEAT TRANSFER, CLASSICAL MECHANICS, AND FLUID DYNAMICS • 上一篇    下一篇

Influence of polymer additives on turbulent energy cascading in forced homogeneous isotropic turbulence studied by direct numerical simulations

李凤臣, 蔡伟华, 张红娜, 王悦   

  1. School of Energy Science and Engineering, Harbin Institute of Technology, Harbin 150001, China
  • 收稿日期:2012-04-15 修回日期:2012-05-08 出版日期:2012-10-01 发布日期:2012-10-01
  • 基金资助:
    Project supported by the National Natural Science Foundation of China (Grant Nos. 51076036 and 51206033), the Foundation for Innovative Research Groups of the National Natural Science Foundation of China (Grant No. 51121004), the Fundamental Research Funds for the Central Universities, China (Grant No. HIT.BRET2.2010008), the Doctoral Fund of Ministry of Education of China (Grant No. 20112302110020), and the China Postdoctoral Science Foundation (Grant No. 2011M500652).

Influence of polymer additives on turbulent energy cascading in forced homogeneous isotropic turbulence studied by direct numerical simulations

Li Feng-Chen (李凤臣), Cai Wei-Hua (蔡伟华), Zhang Hong-Na (张红娜), Wang Yue (王悦 )   

  1. School of Energy Science and Engineering, Harbin Institute of Technology, Harbin 150001, China
  • Received:2012-04-15 Revised:2012-05-08 Online:2012-10-01 Published:2012-10-01
  • Contact: Cai Wei-Hua E-mail:caiwh@hit.edu.cn
  • Supported by:
    Project supported by the National Natural Science Foundation of China (Grant Nos. 51076036 and 51206033), the Foundation for Innovative Research Groups of the National Natural Science Foundation of China (Grant No. 51121004), the Fundamental Research Funds for the Central Universities, China (Grant No. HIT.BRET2.2010008), the Doctoral Fund of Ministry of Education of China (Grant No. 20112302110020), and the China Postdoctoral Science Foundation (Grant No. 2011M500652).

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摘要： Direct numerical simulations (DNS) were performed for the forced homogeneous isotropic turbulence (FHIT) with/without polymer additives in order to elaborate the characteristics of the turbulent energy cascading influenced by the drag-reducing effects. The finite elastic non-linear extensibility-Peterlin model was used as the conformation tensor equation for the viscoelastic polymer solution. Detailed analyses of DNS data were carried out in this paper for the turbulence scaling law and the topological dynamics of FHIT as well as the important turbulent parameters, including turbulent kinetic energy spectra, enstrophy and strain, velocity structure function, small-scale intermittency, etc. A natural and straightforward definition for the drag reduction rate was also proposed for the drag-reducing FHIT based on the decrease degree of the turbulent kinetic energy. It was found that the turbulent energy cascading in the FHIT was greatly modified by the drag-reducing polymer additives. The enstrophy and the strain fields in the FHIT of polymer solution were remarkably weakened as compared with their Newtonian counterparts. The small-scale vortices and the small-scale intermittency were all inhibited by the viscoelastic effects in the FHIT of polymer solution. However, the scaling law in a fashion of extended self-similarity for the FHIT of polymer solution, within the presently simulated range of Weissenberg numbers, had no distinct differences compared with that of the Newtonian fluid case.

关键词: forced homogenous isotropic turbulence, polymer additives, turbulent energy cascading, drag reduction

Abstract: Direct numerical simulations (DNS) were performed for the forced homogeneous isotropic turbulence (FHIT) with/without polymer additives in order to elaborate the characteristics of the turbulent energy cascading influenced by the drag-reducing effects. The finite elastic non-linear extensibility-Peterlin model was used as the conformation tensor equation for the viscoelastic polymer solution. Detailed analyses of DNS data were carried out in this paper for the turbulence scaling law and the topological dynamics of FHIT as well as the important turbulent parameters, including turbulent kinetic energy spectra, enstrophy and strain, velocity structure function, small-scale intermittency, etc. A natural and straightforward definition for the drag reduction rate was also proposed for the drag-reducing FHIT based on the decrease degree of the turbulent kinetic energy. It was found that the turbulent energy cascading in the FHIT was greatly modified by the drag-reducing polymer additives. The enstrophy and the strain fields in the FHIT of polymer solution were remarkably weakened as compared with their Newtonian counterparts. The small-scale vortices and the small-scale intermittency were all inhibited by the viscoelastic effects in the FHIT of polymer solution. However, the scaling law in a fashion of extended self-similarity for the FHIT of polymer solution, within the presently simulated range of Weissenberg numbers, had no distinct differences compared with that of the Newtonian fluid case.

Key words: forced homogenous isotropic turbulence, polymer additives, turbulent energy cascading, drag reduction

中图分类号:  (Isotropic turbulence; homogeneous turbulence)

  • 47.27.Gs
47.50.-d (Non-Newtonian fluid flows) 47.85.lb (Drag reduction)