کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
9693431 1459120 2005 22 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
On the linear stability of plane Couette flow for an Oldroyd-B fluid and its numerical approximation
موضوعات مرتبط
مهندسی و علوم پایه مهندسی شیمی جریان سیال و فرایندهای انتقال
پیش نمایش صفحه اول مقاله
On the linear stability of plane Couette flow for an Oldroyd-B fluid and its numerical approximation
چکیده انگلیسی
It is well known that plane Couette flow for an Oldroyd-B fluid is linearly stable, yet, most numerical methods predict spurious instabilities at sufficiently high Weissenberg number. In this paper we examine the reasons which cause this qualitative discrepancy. We identify a family of distribution-valued eigenfunctions, which have been overlooked by previous analyses. These singular eigenfunctions span a family of non-modal stress perturbations which are divergence-free, and therefore do not couple back into the velocity field. Although these perturbations decay eventually, they exhibit transient amplification during which their “passive” transport by shearing streamlines generates large cross-stream gradients. This filamentation process produces numerical under-resolution, accompanied with a growth of truncation errors. We believe that the unphysical behavior has to be addressed by fine-scale modelling, such as artificial stress diffusivity, or other non-local couplings.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Non-Newtonian Fluid Mechanics - Volume 127, Issues 2–3, 1 May 2005, Pages 169-190
نویسندگان
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