Oscillatory model of vortex-induced oscillations under the influence of wide-band random excitation

Predrag Kozić, Ratko Pavlović

An oscillation system with two degrees of freedom of movement was analyzed in the action of a stationary broadband Gaussian random process in which an aproximation vector was drawn in according to Markov. The liferential equations after the first and second statistical moments of the solution process also contain the statistical moments of the third and fourth order and are determined using the Fokker-Planck equation. With the assumption that the statistical moments of a higher order (higher than 3) can be presented with moments of a lower order, then the system of differential equations is reduced to the so-called. ’’closed system’ reduced. The stationary values of the solution process can then be determined numerically using moments of the first and second order. These values can be represented graphically (Figures 2 and 3) as functions of the spectral density S of the turbulent velocity process of the fluid flow.