# Comprehensive Investigations on Fluid Flow and Cavitation Characteristics in Rotating Disk System
## 1 Introduction
explored the relationship between texture position, texture depth, and oil-film-bearing capacity and found that the bearing capacity could be improved in both converging and diverging regions, and shallow texture in converging regions could better improve lubrication performance, while effect in diverging region was not significant. [PERSON] [20] et al. modeled the spherical crown texture and simplified it dimensionless, simulated the 3D model in Fluent, and found that the increase of Reynolds number and texture depth enhances the fluid-bearing capacity. [PERSON] [21] nondimensionalized the Reynolds equation and established the hydrodynamic-pressure lubrication equation for a non-contact mechanical seal with hemispherical texture and found that as dimple diameter decreases, the oil-bearing capacity and leakage decreases, the torque increases, and the optimal dimple size is related to the viscosity of the oil. [PERSON] [22] et al. used the finite difference method to simulate the effect of columnar texture on dynamic pressure radial bearings, based on analysis of different texture arrangements, and found that the bearing surface texture rate of 100% was not effective in increasing the dynamic bearing capacity, and the best effect was achieved when the attitude angle of the texture was 49\({}^{\circ}\), and the thickness of the oil film was able to increase by 1.8%. [PERSON] [23] et al. investigated the effect of texture rate on sliding bearings and found the stability of bearing operation decreases when the texture rate increases to a certain value; the oil temperature increases by 10% after textured compared to the untextured bearing. Cavitation is specific and occurs in a low pressure region inside liquid, especially at the interface between liquid and solid. Conventionally, cavitation is a phase change from liquid [24; 25; 26; 27]. As shown in Figure 1, the morphological characteristics of the friction pairs severely affect the intensity of shear cavitation [28]. [PERSON] [29] pointed out that when the aircraft is flying in rain or clouds, the edges of the turbofan blades in turbine are affected by cavitation causing surface material loss, which increases the surface roughness of turbofan blades and reduces the efficiency of the aircraft flight. [PERSON] (2018) studied the corrosion effect of fluid cavitation on material surfaces by controlled experiments. A pressure difference was applied in flow field and significant vortices in the flow field with a blunt body was caught by high-speed camera. Through continuous experiments for up to 30 h, it was found that extensive erosion occurred in the flow field with a blunt body. [PERSON] (2018) added abrasives into fluid to finish the internal surfaces of mechanical parts. It was found that tiny abrasive particles increased the cavitation erosion effect and increased the cleaning degree by 90%. [PERSON] (2018) et al. studied the underwater vehicle cavitation and analyzed the special flow due to cavitation bubbles being created, dislodged, and collapsed, which provides guidance for the design of underwater vehicles to prevent cavitation. [PERSON] (2018) studied the effect of microstructured surfaces on cavitation to reduce the hazard level of cavitation of ship propellers and found that the momentum of microjet flow produced by cavitation bubbles ruptured on microstructured surfaces and smooth surfaces was different, and microstructured surfaces can effectively reduce the annular ring after bubbles rupture, while surfaces machined with microporosity can reduce the cavitation area. [PERSON] (2018) analyzed the preventive effect of various coatings on cavitation and found that cavitation always starts at pores or small cracks on the surface of the object, leading to brittle damage of the material as a whole and eventually to large cavitation dimples.