Duration of transient processes in the formation of internal-wave beams

Abstract

the fluid with density ρ in the presence of the gravitational acceleration g directed oppositely to the y axis. The beam width is on the order of the characteristic size of the body. The phase patterns of internal waves for steady-state oscillations and for the impulse displacement of bodies were discussed in [1]. The theoretical solution for internal waves generated by harmonic oscillations of a circular cylinder in a linearly stratified ideal fluid was obtained in [2]. An approximate solution for the case of nonzero fluid viscosity was given in [3]. Various approaches to solving the problem of the emission of internal waves by oscillating bodies in a viscous fluid were also discussed in [4]. A number of problems concerning the viscous mechanism of generating internal waves were considered in [5–7]. The nonstationary problem of the formation of internal-wave beams has been studied less thoroughly. A review of works and the asymptotic solutions of the time-dependent problem concerning internal waves generated by various systems of model singularities were given in [8]. Systematic experimental investigations of transient processes at the initial stage of the formation of internal-wave beams have not yet been carried out. In this work, quantitative experimental estimates for the duration of transient processes are obtained using the correlation analysis of wave-disturbance fields at different times. Ω arcsin ω N ---