Theoretical study of glaze ice accretion on an oscillating cylinder and its aerodynamic characteristics

Abstract

Researchers, through time, have been conducted a series of theoretical and experimental measures on the glaze icing phenomena, but very few literatures can be found to quantify the effects of cylinder oscillation on the evolution of water films and ice shapes, and further to characterize aerodynamic characteristics during the glaze ice accretion process. A preliminary study is carried out to demonstrate a glaze icing process on the upwind face of both fixed and movable cylinder surfaces, and to discuss the cylinder aerodynamic characteristics. Based on the lubrication theory, the coupled masses and energy balances, the evolution of water film and glaze ice growth models on the upwind side of the cylinder are proposed by considering water film thickness, ice thickness, upper rivulet positions and the cylinder acceleration in the vertical direction. Wind pressures and frictions, and aerodynamic coefficients on the cylinders (Non-ice with rivulet, iced with rivulet and non-rivulet) are computed by the computational fluid dynamics (CFD) method. A comparison between the fixed and the moveable cylinders on water films and the ice shapes is carried out, and the effects of the upper rivulet positions and the wind velocities on aerodynamic vibrations of both iced and non-ice cylinders are also discussed further. The results show that the cylinder oscillation has a certain effect on the upper rivulet positions, and further influences on ice shapes. Moreover, the aerodynamic characteristics of the cylinders with upper rivulets are somewhat like wind velocities and amplitude-restricted vibrations. It turns out that the proposed models can capture main features of the glaze icing process, and shed light on more actual glaze ice accretion.