Numerical study of Fermi-Pasta-Ulam recurrence for water waves over finite depth
V. P. Ruban
L.D. Landau Institute for Theoretical Physics RAS, 119334 Moscow, Russia
Abstract
Highly accurate direct numerical simulations have been performed
for two-dimensional free-surface potential flows of an ideal incompressible
fluid over a constant depth h, in the gravity field g. In each numerical
experiment, at t=0 the free surface profile was in the form , and the velocity field v=0. The computations demonstrate the
phenomenon of Fermi-Pasta-Ulam (FPU) recurrence takes place in such systems
for moderate initial wave amplitudes and spatial periods
at least . The time of recurrence T FPU is well
fitted by the formula
.