https://doi.org/10.1140/epjb/e2003-00178-3
Noise correlations in shear flows
1
Fachbereich Physik, Philipps-Universität Marburg,
35032 Marburg, Germany
2
Centre for Condensed Matter Theory, Department of Physics,
Indian Institute of Science, Bangalore, 560 012, India
Corresponding author: a bruno.eckhardt@physik.uni-marburg.de
Received:
26
February
2002
Revised:
11
March
2003
Published online:
20
June
2003
We consider the effects of a shear on velocity fluctuations in a flow. The shear gives rise to a transient amplification that not only influences the amplitude of perturbations but also their time correlations. We show that, in the presence of white noise, time correlations of transversal velocity components are exponential and that correlations of the longitudinal components are exponential with an algebraic prefactor. Cross correlations between transversal and downstream components are strongly asymmetric and provide a clear indication of non-normal amplification. We suggest experimental tests of our predictions.
PACS: 47.27.-i – Turbulent flows, convection, and heat transfer / 05.40.Ca – Noise / 47.20.Ft – Instability of shear flows
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2003
