Hydrodynamic forces and flow pattern of four kinds of cavitating grid fins with cavitation number from 2.5 to 0.25 were simulated numerically with a bubble two-phase flow model embodied in the commercial CFD code Flue...Hydrodynamic forces and flow pattern of four kinds of cavitating grid fins with cavitation number from 2.5 to 0.25 were simulated numerically with a bubble two-phase flow model embodied in the commercial CFD code Fluent 6.0. Comparison with experimental datum showed that rules of hydrodynamic forces changing with cavitation number were coordinated with experiment, and cavitation made the ratio of lift to resistance decrease. Calculated axial force and chordal pressure center in all-wetted condition or those at cavitation number less than 0.75 agreed well with experiments. Normal force in all-wetted condition was less by 20 per cent. The differences between computation and experiment in the total range of cavitation number were mainly because that the incipient cavitation number in computation was less than that at experiment.展开更多
A two-phase mixture model based on the solution for the Navier-Stokes equations has been utilized in calculating the hydrodynamic characteristics of cavitating honeycomb grid fins with different configurations. The ca...A two-phase mixture model based on the solution for the Navier-Stokes equations has been utilized in calculating the hydrodynamic characteristics of cavitating honeycomb grid fins with different configurations. The calculation results of lift, drag, and hinge moment coefficients are presented in various cavitation numbers and angles of attack, and its hydrodynamic features are also analyzed. The calculation results indicate that cavitation will reduce the lift/drag ratio of grid fins. The increment of horizontal blades as lift surface cannot unendingly improve lift because of the disturbance between the blades.展开更多
基金the National Natural Science Foundation of China (Grant No: 10372061) and the Doctor Foundation (Grant No: 20030248001)
文摘Hydrodynamic forces and flow pattern of four kinds of cavitating grid fins with cavitation number from 2.5 to 0.25 were simulated numerically with a bubble two-phase flow model embodied in the commercial CFD code Fluent 6.0. Comparison with experimental datum showed that rules of hydrodynamic forces changing with cavitation number were coordinated with experiment, and cavitation made the ratio of lift to resistance decrease. Calculated axial force and chordal pressure center in all-wetted condition or those at cavitation number less than 0.75 agreed well with experiments. Normal force in all-wetted condition was less by 20 per cent. The differences between computation and experiment in the total range of cavitation number were mainly because that the incipient cavitation number in computation was less than that at experiment.
基金Project supported by the National Natural Science Foundation of China (Grant No: 10372061)the National Defense Technology Key Laboratory on Hydrodynamics
文摘A two-phase mixture model based on the solution for the Navier-Stokes equations has been utilized in calculating the hydrodynamic characteristics of cavitating honeycomb grid fins with different configurations. The calculation results of lift, drag, and hinge moment coefficients are presented in various cavitation numbers and angles of attack, and its hydrodynamic features are also analyzed. The calculation results indicate that cavitation will reduce the lift/drag ratio of grid fins. The increment of horizontal blades as lift surface cannot unendingly improve lift because of the disturbance between the blades.
