T. Clune, M.C. Depassier and E. Knobloch

Long wavelength oscillatory instability in binary fluids

In: Instabilities and Nonequilibrium Structures V. (E. Tirapegui and W. Zeller, eds.) Kluwer Academic., 1996, 75-84.


Binary fluid convection takes the form of oscillations for sufficiently negative separation ratios. When the confining plates are of poor thermal conductivity these oscillations have a long wavelength. Nonlinear planform equations governing the resulting instability are derived for both two and three dimensions. The technique uses a multiple scale analysis combined with reconstitution. The validity of the resulting equations is discussed and compared with asymptotically exact alternatives. The results are found to differ demonstrating the failure of the reconstitution procedure.