Turbulence effects on fluidelastic instability of a cylinder in a shear flow

Fluidelastic instability is the main mechanism that causes severe damages in flow-induced vibration. Experiments show that grid-generated turbulence can affect the stability of the system, which is modeled as an Ornstein–Uhlenbeck process. The dynamic stability of a four-dimensional system under real noise excitation is studied through the determination of the p th moment Lyapunov exponent and the Lyapunov exponent. The partial differential eigenvalue equation governing the moment Lyapunov exponent is established. For small noise amplitudes, a method of regular perturbation is used to determine analytical expansions of the moment Lyapunov exponents and Lyapunov exponents, which are shown to be in good agreement with those obtained using numerical approaches. The analytical method is applied to study the stability of a cylinder in a shear flow, where fluidelastic instability is known to occur. The results demonstrate that the unstable system can be stabilized under certain conditions and the effect of stabilization is proportional to the turbulence intensity, which agrees with experimental observations.