## 4 Simulation Results and Discussions
The node pressure patterns along the line of \(b_{1}\)-\(b_{2}\) for different OLDRs are depicted in Figure 3:0 It can be found from Figure 7 that the oil pressure is nearly symmetric with respect to the node position of 58 mm. The maximum node pressure is located at the node position of 58 mm, and then a pressure drop and a limited pressure recovery occur further downstream. The node pressure has a linear decrease in the sealing land regions. The maximum node pressure for different OLDRs decreases as in the sequence of OLDRs of 0.25, 0.5, 1, 2, 3, 4, 5. However, the node pressure for different OLDRs decreases as in the sequence of OLDRs of 2, 3, 1, 4, 5, 0.5, 0.25 in the zone of II. It can be concluded that a too large or too small OLDR is not conducive to pressure maintenance. The velocity magnitude patterns along the line of \(b_{1}\)-\(b_{2}\) for different OLDRs are depicted in Figure 3:1 It can be found from Figure 8 that the distribution of fluid velocity magnitude is M-shaped and is almost symmetric with respect to the node position of 58 mm. There are four stages of the fluid velocity variation along the flow direction: acceleration-deceleration-acceleration-nearly uniform speed. The velocity magnitudes are very low at the node position of 58 mm for different OLDRs, which decrease as in the sequence of OLDRs of 2, 4, 5, 0.25, 0.5, 1, 3. The velocity magnitude is rapidly accelerated to the maximum value within a radius of 0.6 mm, which is increased by about 6 times. The maximum velocity magnitudes for various OLDRs decrease as in the sequence of OLDRs of 0.25, 0.5, 1, 2, 3, 4, 5. It can be concluded that the smaller the OLDR is, the larger  
Figure 3:2 Pressure patterns of various OLDRs along the line of \(b_{1}\)-\(b_{2}\). (**a**) Node pressures of various OLDRs along the line of \(b_{1}\)-\(b_{2}\); (**b**) local enlarged view of I; (**c**) local enlarged view of II. the maximum velocity magnitude is. Furthermore, the maximum velocity magnitudes of OLDRs of 0.25 and 0.5 are almost equal, presenting that further reduction of the OLDR has few effects on the maximum velocity magnitude. When the velocity magnitude reaches its maximum value, it begins to decrease. As the fluid flows out of the annular recess, the small clearance of the sealing lands that follows offers an increased resistance to flow, causing a considerable acceleration of the flow. Finally, the fluid flows out of the sealing lands at a nearly uniform velocity. The turbulent intensity patterns along the line of \(b_{1}\)-\(b_{2}\) for different OLDRs are depicted in Figure 3:3 It can be found from Figure 9 that the pattern of turbulent intensity of each OLDR is almost symmetric with respect to the node position of 58 mm. The maximum turbulent intensity occurs near the center of the orifice inlet and it continually decreases along the flow direction until the fluid reaches near the boundary between the annular recess and the sealing lands. Then, a limited turbulent intensity recovery occurs further downstream. Finally, the fluid flows out of the sealing lands at a nearly uniform low-level turbulent intensity. The maximum turbulent intensity for different OLDRs decreases as in the sequence of OLDRs of 0.5, 0.25, 1, 2, 3, 4, 5. Furthermore, the turbulent intensities of OLDRs of 0.25 and 0.5 are almost equal, presenting that further reduction of the OLDR has little effect on the turbulent intensity. Figure 3:4 Velocity magnitude patterns of various OLDRs along the line of \(b_{1}\)–\(b_{2}\). (**a**) Velocity magnitudes of various OLDRs along the line of \(b_{1}\)–\(b_{2}\); (**b**) local enlarged view of I; (**c**) local enlarged view of \(\Pi\). The line of \(a_{1}\)-\(a_{2}\) is one part of the operating wall \(S\) which is the boundary wall of the oil film. The node pressure patterns along the line of \(a_{1}\)-\(a_{2}\) for different OLDRs are depicted in Figure 3:5 It can be found from Figure 10 that the node pressure profile along the line of \(a_{1}\)-\(a_{2}\) is similar to that of the line of \(b_{1}\)-\(b_{2}\).