A Quasi-Steady 3-DoFs Sectional Aerodynamic Model: Preliminary Results

A generalized quasi-steady three-degrees-of-freedom analytical model, capable of predicting the aerodynamic instability of a cylinder with a generic cross-section, is proposed. The three degrees-of-freedom refer to the two orthogonal displacements, perpendicular to the body’s axis, plus the rotation about the longitudinal body axis. It allows for the variation of the force coefficients, i.e., drag, lift, and moment, with Reynolds number based on the relative flow velocity, with relative angle-of-attack, and relative cable-wind angle. The aerodynamic forces acting on the structure are linearized around the static equilibrium configuration. Based on the analytical solution of the eigenvalue problem, an expression of the galloping- and static divergence-type instability condition is derived. Finally, an application of the model is proposed to study the galloping of a full-scale dry inclined/yawed cable.