Direct numerical experiment on measuring of dispersion relation for gravity waves in the presence of condensate
A. O. Korotkevich
Department of Mathematics and Statistics, University of New Mexico,
MSC01 1115, 1 University of New Mexico, Albuquerque, NM 87131-0001, USA
Landau Institute for Theoretical Physics of the RAS, 119334 Moscow, Russia
Abstract
During previous numerical experiments on isotropic turbulence of
surface gravity waves we observed formation of the long wave background
(condensate). It was shown (Korotkevich, Phys. Rev. Lett. 101(7),
074504 (2008)), that presence of the condensate changes a spectrum of direct
cascade, corresponding to the flux of energy to the small scales from pumping
region (large scales). Recent experiments show that the inverse cascade
spectrum is also affected by the condensate. In this case mechanism proposed
as a cause for the change of direct cascade spectrum cannot work. But inverse
cascade is directly influenced by the linear dispersion relation for waves,
as a result direct measurement of the dispersion relation in the presence of
condensate is necessary. We performed the measurement of this dispersion
relation from the direct numerical experiment. The results demonstrate that
in the region of inverse cascade influence of the condensate cannot be
neglected.