# An Experimental Study on Ice Accretion under Bridge Cable in Different Conditions
## 3 Results and Discussion
### Effect of Change of Inclination Angle and Diameter of Cable on Bottom Lcing Condition  
In Figure 10a-c, under the same temperature condition, the maximum length of the icicle decreases with the increase of the angle of the stay cable. When the inclination angle of the stay cable increases from 0\({}^{\circ}\) to 60\({}^{\circ}\), the decrease of the maximum length of the icicle varies from 66 mm to 310 mm and decreases to 0 when the inclination angle is 60\({}^{\circ}\), which indicates that the increase of the inclination angle will reduce the length of the bottom icicle, that is, too large an inclination angle will inhibit the growth of the icicle. This is because an increase in inclination will reduce the mass of the intercepted droplets, so the amount of liquid water that can reach the bottom area of the stay cable will decrease [14]. That is, the droplet impingement surface reduces, and the droplet flows inertia on the surface of the stay cable increases. As a result, the droplet collection efficiency on the surface of the stay cable decreases, and the amount of water that can reach the bottom falls.  
Figure 9: (**a–d**) Influence of ambience on ice rib width.  
Figure 10: _Cont._  
Additionally shown in Figure 10a-c, under the same temperature, the maximum length of the icicle decreases between 112 mm and 310 mm in D1 and D2 with the increase of angle, while the maximum length decreases between 66 mm and 82 mm in D3. It can be seen that the change in the cable diameter will also affect the maximum length of the icicle because the decrease in the cable diameter will increase the droplet collision efficiency. [PERSON] et al. [27] pointed out in their analysis of the icing flow field that for a cylinder with a large diameter, the resistance of the droplets overcomes the inertial force, which makes them more inclined to follow the airflow line and bypass the cylinder.  
Figure 11 shows the trend of the number of icicles changing with the inclination angle and diameter of the stay cable when the ambient temperature remains unchanged. It can be seen that, under the same ambient temperature conditions, the number of icicles gradually decreases as the inclination angle of the cable (2 m) increases; as the inclination angle of the cable increases from 0\({}^{\circ}\) to 60\({}^{\circ}\), the reduction in the number of D1 icicles varies from 19 to 55, and the decrease in the number of D2 icicles varies from 13 to 49. The reduction in the number of D3 icicles varies from 7 to 18, no L2 icicles appear at any time, and no icicles are formed when the inclination angle is 60\({}^{\circ}\). This indicates that the increase in the angle of inclination inhibits the growth of icicles to some extent. This phenomenon was also verified by [PERSON] et al. [28]. The increase in inclination angle leads to an increase in the effective impact velocity of the droplets, resulting in a decrease in ice accumulation in the upper part [29; 30; 31; 32]. The lower piece of the inclined rope does not have access to sufficient material, thus inhibiting ice formation on the bottom surface.  
Figure 10: (**a**–**c**) Influence of cable inclination angle on maximal length of icicles.  
Figure 11: _Cont._  
In Figure 11, the smaller the diameter, the greater the number of icicles formed for a given inclination of the diagonal cable, and, again, more icicles were formed for L \(\geq\) 100 mm. In the studies by [PERSON] [33] and [PERSON] et al. [27], appropriate inclination angles and smaller diameters helped to increase the efficiency of droplet collision with the sloping cable surface, which, to some extent, increased the efficiency of liquid water collection on the cable surface, which in turn increased the water supply to the bottom surface, allowing the number of icicles to increase.