Sand wave formation: a linear instability mechanism

The results for a height and flow-dependent model for turbulent viscosity are reported. This model is developed to explain the generation of sand waves in tidal seas and resolves the problem of excitation of very long waves in sand wave formation, because it leads to damping of the long waves and gives a finite separation between the most excited mode and the zero mode. For parameter settings within a physically realistic range, a linear analysis of the resulting system yields a first excited mode whose wavelength is similar to the characteristic wavelength of sand waves observed in nature. This result can be the starting point for a nonlinear analysis of the system