Preface

摘要

Nonconservative mechanical systems have been known about since the end of the nineteenth century when Greenhill posed a problem on the buckling of a screw shaft of a steamer subject to both an end thrust and an axial torque. In the 1920s, Nicolai introduced a follower torque into the Greenhill problem and demonstrated a dynamic instability (flutter) of the shaft. In the 1930s, Theodorsen presented a model of flutter of flexible structures in a flow and derived circulatory lift and drag forces. In the 1950s, Ziegler proposed a classification of conservative and non-conservative loads, distinguishing nonpotential positional forces that produce nonzero work on a closed contour, and, inspired by aerodynamics, called them circulatory. Nearly at the same time as Greenhill published his work, Kelvin and Tait, studying models of formation of binary stars, discovered the destruction by viscosity of gyroscopic stabilization of rotating ellipsoidal masses of fluid. This was the first example of dissipation-induced instabilities. Nowadays dissipative and circulatory forces are recognized as the two fundamental nonconservative forces in a growing number of scientific and engineering disciplines including physics, fluid and solid mechanics, fluid-structure interactions, and modern multidisciplinary research areas such as biomechanics, micro- and nanomechanics, optomechanics (for instance, optical tweezers generate a circulatory force field), robotics, energy harvesting, and material science.