EPJ Web Conf.
Volume 137, 2017XIIth Quark Confinement and the Hadron Spectrum
|Number of page(s)||11|
|Section||Section G: Strongly Coupled Theories|
|Published online||22 March 2017|
Advection of a passive scalar field by turbulent compressible fluid: renormalization group analysis near d = 4
1 Department of Theoretical Physics, Faculty of Physics, Saint-Petersburg State University, 7/9 Universitetskaya nab., St. Petersburg, 199034 Russia
2 Faculty of Sciences, P.J. Šafárik University, Moyzesova 16, 040 01 Košice, Slovakia and Fakultät für Physik, Universität Duisburg-Essen, D-47048 Duisburg, Germany
Published online: 22 March 2017
The field theoretic renormalization group (RG) and the operator product expansion (OPE) are applied to the model of a density field advected by a random turbulent velocity field. The latter is governed by the stochastic Navier-Stokes equation for a compressible fluid. The model is considered near the special space dimension d = 4. It is shown that various correlation functions of the scalar field exhibit anomalous scaling behaviour in the inertial-convective range. The scaling properties in the RG+OPE approach are related to fixed points of the renormalization group equations. In comparison with physically interesting case d = 3, at d = 4 additional Green function has divergences which affect the existence and stability of fixed points. From calculations it follows that a new regime arises there and then by continuity moves into d = 3. The corresponding anomalous exponents are identified with scaling dimensions of certain composite fields and can be systematically calculated as series in y (the exponent, connected with random force) and ε = 4 − d. All calculations are performed in the leading one-loop approximation.
© The Authors, published by EDP Sciences, 2017
This is an Open Access article distributed under the terms of the Creative Commons Attribution License 4.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
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