An investigation made on the rotor blade tip vortex through use of a Three Dimensional Laser Doppler Velocimetry(3D LDV) is described. The experiment is conducted with a 2 m in diameter model helicopter rotor. By a ...An investigation made on the rotor blade tip vortex through use of a Three Dimensional Laser Doppler Velocimetry(3D LDV) is described. The experiment is conducted with a 2 m in diameter model helicopter rotor. By a series of measurements near blade tip, the velocity field near blade tip is documented, and through which, the tip vortex rollup and development are presented. The radial distribution of instantaneous velocities at various levels above and under the rotor disc is also measured in this investigation. Using this distribution, the influence of the tip vortex from the preceding blade on the follow up blade is discussed.展开更多
This paper presents an experimental investigation on flow field induced by a dielectric barrier discharge(DBD) plasma actuator with serrated electrodes in still air to further improve its flow control effectiveness. F...This paper presents an experimental investigation on flow field induced by a dielectric barrier discharge(DBD) plasma actuator with serrated electrodes in still air to further improve its flow control effectiveness. For comparison, the actuator with widely used linear electrodes was also studied. Experiments were carried out using 2D particle image velocimetry. Particular attention was given to the flow topology, discharge phenomenon, and vortex formation mechanism. Results showed that a 2D wall jet was induced by the linear actuators, whereas the plasma actuators with serrated electrode introduced a series of streamwise vorticities, which might benefit flow control(e.g., enhancing the momentum transport in the separated boundary flow). In addition, the mechanism of 3D flow topology induced by the serrated DBD actuator was analyzed in detail.展开更多
文摘An investigation made on the rotor blade tip vortex through use of a Three Dimensional Laser Doppler Velocimetry(3D LDV) is described. The experiment is conducted with a 2 m in diameter model helicopter rotor. By a series of measurements near blade tip, the velocity field near blade tip is documented, and through which, the tip vortex rollup and development are presented. The radial distribution of instantaneous velocities at various levels above and under the rotor disc is also measured in this investigation. Using this distribution, the influence of the tip vortex from the preceding blade on the follow up blade is discussed.
基金supported by the National Natural Science Foundation of China (51222606)
文摘This paper presents an experimental investigation on flow field induced by a dielectric barrier discharge(DBD) plasma actuator with serrated electrodes in still air to further improve its flow control effectiveness. For comparison, the actuator with widely used linear electrodes was also studied. Experiments were carried out using 2D particle image velocimetry. Particular attention was given to the flow topology, discharge phenomenon, and vortex formation mechanism. Results showed that a 2D wall jet was induced by the linear actuators, whereas the plasma actuators with serrated electrode introduced a series of streamwise vorticities, which might benefit flow control(e.g., enhancing the momentum transport in the separated boundary flow). In addition, the mechanism of 3D flow topology induced by the serrated DBD actuator was analyzed in detail.
