Abstract
The authors describe a stationary solution to the non-linear, dispersive field equation, rho utt=cuxx+Cuxuxx+huxxxx for the field u(x,t), (a) defined in the range -l<or=x<or=l and (b) clamped at the boundaries u(+or-l,t)=0. The solution is characterized by a cyclic exchange of energy between the two lowest-frequency modes. Expressions are derived for the period and amplitudes of the energy exchange in terms of the parameters rho , c, C, h and l.