We study the spectral properties of the advection-diffusion operator associated with a non-chaotic 3d Stokes flow defined in the annular region between counter-rotating cylinders of finite length. The focus is on the dependence of the eigenvalue-eigenfunction spectrum on the Peclet number Pe. Several convection-enhanced mixing regimes are identified, each characterized by a power law scaling, -μd∼Pe-γ (γ<1) of the real part of the dominant eigenvalue, -μd, vs.Pe. Among these regimes, a Pe-independent scaling -μd=const (i.e., γ=0), qualitatively similar to the asymptotic regime of globally chaotic flows, is observed. This regime arises as the consequence of different eigenvalues branches interchanging dominance at increasing Pe. A combination of perturbation analysis and functional-theoretical arguments is used to explain the occurrence and the range of existence of each regime. © 2008 Europhysics Letters Association.

Complex spectral properties of non-Hermitian operators: An application to open-flow mixing systems / Giona, Massimiliano; Cerbelli, Stefano; F., Garofalo. - In: EUROPHYSICS LETTERS. - ISSN 0295-5075. - 83:3(2008), pp. 34001-34001-6. [10.1209/0295-5075/83/34001]

Complex spectral properties of non-Hermitian operators: An application to open-flow mixing systems

GIONA, Massimiliano;CERBELLI, Stefano;
2008

Abstract

We study the spectral properties of the advection-diffusion operator associated with a non-chaotic 3d Stokes flow defined in the annular region between counter-rotating cylinders of finite length. The focus is on the dependence of the eigenvalue-eigenfunction spectrum on the Peclet number Pe. Several convection-enhanced mixing regimes are identified, each characterized by a power law scaling, -μd∼Pe-γ (γ<1) of the real part of the dominant eigenvalue, -μd, vs.Pe. Among these regimes, a Pe-independent scaling -μd=const (i.e., γ=0), qualitatively similar to the asymptotic regime of globally chaotic flows, is observed. This regime arises as the consequence of different eigenvalues branches interchanging dominance at increasing Pe. A combination of perturbation analysis and functional-theoretical arguments is used to explain the occurrence and the range of existence of each regime. © 2008 Europhysics Letters Association.
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Complex spectral properties of non-Hermitian operators: An application to open-flow mixing systems / Giona, Massimiliano; Cerbelli, Stefano; F., Garofalo. - In: EUROPHYSICS LETTERS. - ISSN 0295-5075. - 83:3(2008), pp. 34001-34001-6. [10.1209/0295-5075/83/34001]
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11573/230320
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