IMA Journal of Applied Mathematics Advance Access published online on February 9, 2007
IMA Journal of Applied Mathematics, doi:10.1093/imamat/hxm002
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Explicit modulation equations, Reynolds averaging and the closure problem for the Korteweg-deVriesBurgers equation

School of Mathematics, The University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
Email: smithwar{at}maths.bham.ac.uk
Received on 5 December 2005; Revision received 5 January 2007.
| Abstract |
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Original explicit modulation equations are determined for cnoidal waves of the Korteweg-deVries (KdV)Burgers equation. This formal asymptotic analysis is used to demonstrate that there is no single partial differential equation for the leading-order mean velocity. The technique of Reynolds averaging is also employed to determine an equation for the mean velocity with the familiar closure problem being encountered. The Reynolds-averaged KdVBurgers equation is shown to be a counterexample to the existence of a closure associated with a convective nonlinearity.
Keywords: strongly nonlinear analysis; Reynolds averaging.