###### Abstract  
Rotating machinery in cold and humid regions is prone to icing. For exploring the characteristics of icing on objects rotating around a vertical axis, such as vertical axis wind turbines (VAWT), a cylinder rotating around the vertical axis was selected as the research object in this study. Three cylinders with different diameters were selected, and icing tests carried out under different tip speed ratios (TSR) in a self-built icing wind tunnel. The icing characteristics were quantitatively analyzed using characteristic parameters, including the icing area, the dimensionless icing area, the stagnation point thickness and the dimensionless stagnation point thickness. The dimensionless stagnation point thickness decreased with increases in the diameter of the cylinder. The icing limit decreased with an increase in the rotational speed of the cylinder, and reached 50% under the high TSR condition. Various icing characteristics were also analyzed for two rotation modes: rotation around the vertical axis and around the horizontal axis. The research findings in the present study lay the theoretical and experimental foundations for exploring VAWT icing in depth. low temperature; humid environment; vertical axis wind turbine; icing; rotating cylinder; wind tunnel test 27 September 2021 3 November  
aircraft wing surface [13]. [PERSON] studied the characteristics of the ice accretion occurring on a large wind turbine blade surface and the effect of the ice formation on the performance of the wind turbine, using an icing wind tunnel test and numerical simulation [14]. [PERSON] predicted the sizes, the shapes and the types of icing at several cross sections along the blade span using a blade element momentum tool, and the power loss due to icing was also evaluated. The calculation results showed good agreement with the AERTS results [15]. [PERSON] computed the ice shapes along the blade span using a two-dimensional ice accretion simulation and established the shedding time and location using a robust and efficient numerical multi-step icing simulation tool [16]. [PERSON] comparatively analyzed the simulation results for the flow behaviors and the resultant ice accretion for 2D and 3D numerical approaches [17]. The author also carried out experimental research on the ice accretion on S826 and S832 airfoil blades and calculated the degradation of the aerodynamic performance using computational fluid dynamics (CFD) [18]. [PERSON] implemented the Ruff scaling method to scale the atmospheric icing conditions and studied the icing shape of a scaled-down model of the blade. The experimental results showed good agreement with simulation results using LEWICE [19]. [PERSON] carried out experiments on the icing of a rotating blade with an NACA0018 airfoil [20; 21]. [PERSON] carried out a field study of ice accretion on a realistic wind turbine blade and predicted the ice thickness distribution using the icing similarity concept and blade element momentum theory [22; 23]. However, there are many different types of airfoil blades in HAWTs, and they have complex curved surfaces. This raises a difficulty in exploring the mechanism of icing on wind turbines. Therefore, empirical ice accretion models have been developed by some scholars and cited by IEA Wind TCP Task 19, which simplify the HAWT blade to a cylinder [24]. In this way, the empirical ice accretion model can simulate the growth of ice on structures under different atmospheric conditions. It provides results in a much shorter period of time for theory and experiments and uses empirical relationships to solve the flow field rather than using the more expensive CFD models. It is a practical method of carrying out basic research on wind turbine blade icing. [PERSON] examined the process and the shape of icing on a non-rotating cylinder surface and quantitatively analyzed the characteristics of icing via heat transfer [25; 26]. [PERSON] established a simulation model for icing on a non-rotating cylinder and carried out icing tests in an icing wind tunnel [27; 28].