Analysis of hydrodynamic characteristics of oblique flow angle to semisubmerged blade profile

Abstract

To analyze the mechanism of the hydrodynamic characteristics of oblique flow angle to surface piercing propeller under natural ventilation, the cup section of an 841-B surface piercing propeller with a dimensionless radius of 0.7 was modeled. A reliable numerical method was established by solving the RANS equation to simulate the water entry process of the cup section combined with standard <i>k-ε</i> turbulence model, VOF method, and overlapping grid technique. On this basis, the hydrodynamic characteristics of the surface piercing propeller cup section under different oblique flow angles were studied, and the free liquid surface form, ventilation cavity form, flow field form, and surface pressure distribution of the surface piercing propeller cup section under different oblique flow angles were analyzed. Results show that increasing the oblique flow angle of the surface piercing propeller cup section will promote the ventilation phenomenon in the water entry process. In addition, increasing the oblique flow angle of the surface piercing propeller cup section will indirectly increase the immersion depth. As a result, the transverse force coefficient and vertical force coefficient of the surface piercing propeller cup section will increase further. Therefore, the influence mechanism of the transmission shaft and working condition on its oblique flow angle should be considered in the engineering application of surface piercing propeller.