화학공학소재연구정보센터
Journal of Non-Newtonian Fluid Mechanics, Vol.129, No.1, 56-60, 2005
The influence of finite extensibility on the eigenspectrum of dilute polymeric solutions
Linear stability of plane Couette flow of dilute polymeric solutions modeled using the FENE-P constitutive equation has been examined. Specifically, the spurious, discrete and continuous spectra are identified as a function of the ratio of the solvent to the total viscosity beta, maximum chain length L, disturbance wavenumber alpha and the Weissenberg number (We). It is observed that reducing L shifts the entire spectrum to the left (in the eigenspectrurn plane) by a factor directly related to the steady-state value of the Peterlin function f. Additionally, decreasing the value of L causes the splitting of the regular continuous spectrum, initially located at -1/We, into two branches. Overall, the plane Couette flow of a FENE-P model is found to be unconditionally stable. Specifically, decreasing L increases the decay rate of the most dangerous disturbance while increasing the number of discrete and spurious modes. However, increasing both P and 01 decreases the number of discrete and spurious modes whereas increasing We has no influence on the number of spurious modes but results in an increase in the number of discrete modes. (c) 2005 Elsevier B.V. All rights reserved.