## 2 Ice Accretion Tests
### Ice Accretion Parameters  
For the ice accretion on a circular cylinder, the symbols and parameters are depicted in Figure 4. The radial ice (the upper ice from the starting point to the ending point) thickness at \(\theta\) (\(\delta_{\theta}\)) around the cylinder circumference in the range of \(\theta=-100^{\circ}\) to \(100^{\circ}\) with an increment of \(5^{\circ}\) or \(10^{\circ}\) were measured. The \(\delta_{\theta}\) values (which were equal to the distance from the auxiliary line (Figure 4) to the cylinder subtracted the distance from the auxiliary line to the ice surface) were measured at six cross sections with distances of 100 mm by a cooled vernier caliper, and the averages were taken as the final results. To describe the icing range of the radial ice, \(\mu\) was defined as the ratio of the ice-covered arc length to the circumference of cylinder (excluding the icicle area). And \(\mu\) = (the circumference of cylinder - the ice-free arc length of cylinder)/the circumference of cylinder. The ice-free arc length was measured by a tape measure. An icicle was composed of a curved part and a linear part. The curved part was attached to the cylinder as droplets flowed down along the circumference. The linear part was under the cylinder, which pointed vertically downward as the run-down water froze under the curved part. The length, longitudinal (along the length direction) top width, longitudinal bottom  
\begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Section Type** & **Section Size (mm)** & **Length \(L\) (mm)** & **Angle \(\gamma\) (\({}^{\circ}\))** & **Spraying Times \(N\)** \\ \hline Circular cylinder & \(\mathcal{O}1000\), \(\mathcal{O}800\), \(\mathcal{O}600\) & 1000 & 0 & 240 \\ Circular cylinder & \(\mathcal{O}400\), \(\mathcal{O}300\), \(\mathcal{O}200\), & 1000 & 0 & 160 \\ Circular cylinder & \(\mathcal{O}150\), \(\mathcal{O}100\), \(\mathcal{O}50\), \(\mathcal{O}25\) & 1000 & 10, 20, 30,40, 50, 60 & 80 \\ Angle steel & L160, L100, L50 & 1000 & 0, 180 & 80 \\ U-steel & U200, U140, U100 & 1000 & 0, 90 & 80 \\ I-beam & 1250, I200, I100 & 1000 & 0 & 80 \\ Girder A & \(324\times 417\) (scale 1: 6) & 1030 & 0 & 30 \\ Girder B & \(536\times 336\) (scale 1: 5) & 1000 & 0 & 30 \\ Girder C & \(625\times 453\) (scale 16: 4) & 1200 & 0 & 30 \\ \hline \hline \end{tabular}
\end{table}
Table 1: Summary of icing test cases.  
Figure 3: Schematic diagram of cross section (unit: mm): (**a**) girder A, (**b**) girder B and (**c**) girder C.  
width, and longitudinal center-to-center spacing of the linear parts of the icicles (denoted as \(l\), \(d_{t}\), \(d_{b}\), and \(s\), respectively) were recorded which were measured by a band tape. The ice profiles were also recorded by taking photographs of their front, top, and bottom views.  
For the section steel, the average ice thicknesses on the top, bottom, and lateral walls (denoted as \(B_{t}\), \(B_{b}\), and \(B_{s}\), respectively), the icicle lengths on the top, bottom, and lateral walls (denoted as \(l_{t}\), \(l_{b}\), and \(l_{s}\), respectively), and the center-to-center spacings of the icicles on the top, bottom, and lateral walls (denoted as \(s_{t}\), \(s_{b}\), and \(s_{s}\), respectively) were measured.  
For the bridge girder, the ice thicknesses on the guardrail, grate plate, truss, and pipeline were measured at six cross sections, and the average values were considered as the final results. The measurement of the icicle size was the same as that of the section steel. Due to component interference, only \(\delta_{0}\) and \(\mu\) were measured for radial ice accretion of the pipeline. The longitudinal and transverse width, and thickness of the grate plate were measured. Measurement of the ice size of the circular component of the guardrail was the same as that of the pipeline, and the uniform thicknesses on the surface of the other components were measured.