Electrically Controlled Rotor Blade Vortex Interaction Airloads and Noise Analysis Using Viscous Vortex Particle Method

Su, Taoyong; Lu, Yang; Ma, Jinchao; Guan, Shujun

doi:10.1155/2019/9678970

Cited by 3 publications

(5 citation statements)

References 32 publications

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“…Sample ECR BVI Load and Noise. The accuracy of a model developed based on the viscous vortex method to predict the ECR BVI load and noise and analyzed the effect of blade preindex angle parameters, which is defined as the blade pitch at three-quarter span station when the ECR is stationary, specific to ECR blades on such load and noise is presented in reference [25]. To ensure the integrity of the paper, the calculated results of the sample ECR parameters and the ECR BVI load and noise at various preindex angles are given in this paper; the detailed model validation and analysis of the results are presented in reference [25].…”

Section: Results and Analysismentioning

confidence: 99%

“…Reference [25] analyzed the BVI load and noise characteristics for the sample ECR with preindex angles of 4 °, 6 °, and 8 °, as shown in Figures 8 and 9. The BVI noise footprints of ECR are predicted on a horizontal plane placed 1.1075R below the rotor hub.…”

Section: Results and Analysismentioning

confidence: 99%

“…The findings of our previous study regarding the mechanism of the BVI of an electrically controlled rotor indicate that the BVI phenomenon on the advancing side of rotor principally occurs because the flap has a larger downward deflection angle in the second quadrant and the strong flap tip vortexes move with the incoming flow to the first quadrant and interact with the blade; the BVI phenomenon on the retreating side is similar to that of a conventional rotor and is principally caused by the interaction of the blade tip vortex from the third quadrant with the blade in the fourth quadrant [25]. Therefore, for the advancing side BVI noise control, the nonharmonic amplitude of the flap should be negative to reduce the downward deflection of the electrically controlled rotor flap on the advancing side, which in turn reduces the flap tip vortex and ultimately reduces the BVI-induced noise on the advancing side of the electrically controlled rotor; for the retreating side BVI noise control, the nonharmonic amplitude of flap should be positive to reduce the pitch of electrically controlled rotor blade on the retreating side through the air-elastic action, which in turn reduces the blade tip vortex and ultimately reduces the BVI-induced noise on the retreating side of the electrically controlled rotor.…”

Section: Computational Model Of Aerodynamic Noise In the Bvimentioning

confidence: 99%

“…Our previous research on the generation mechanism of electrically controlled rotor BVI has demonstrated that there are not only concentrated blade tip vortices in the wake flow field of electrically controlled rotors but there are also strong flap tip vortices when the flap deflection is significant [4]; the flap tip vortices released in the second quadrant convect downstream and produce the advancing side interactions, while the blade tip vortices released in the third quadrant convect downstream and produce the retreating side interactions [25]. At present, research on active control methods based on ACFs is focused on single-frequency harmonic and combined harmonic control; based on the BVI generation mechanism of electrically controlled rotors, nonharmonic inputs are introduced in the local azimuth range to reduce the wake vortex strength at the corresponding azimuth position, which can not only reduce the BVI-induced noise of electrically controlled rotors but also reduce the dependence on the closed-loop control system to some extent.…”

Section: Introductionmentioning

confidence: 99%

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Nonharmonic Control of the Blade-Vortex Interaction Noise of Electrically Controlled Rotor

Ke-wei

et al. 2022

International Journal of Aerospace Engineering

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Electrically controlled rotor, also known as swashplateless rotor, represents an active rotor system that, due to the use of a trailing edge flap system instead of a swashplate, not only enables primary control but also conveniently reduces the blade-vortex interaction (BVI) noise of the rotors through active control. The effect of nonharmonic inputs on the control of the BVI noise of electrically controlled rotors based on their unique trailing edge flap systems has been investigated in this paper. To this end, an analytical model for the vortex interaction-induced load and noise of electrically controlled rotor is first established based on the viscous vortex particle method, the Weissinger-L blade model, and the Ffowcs Williams-Hawkings (FW-H) equation. On this basis, a simulation study of flap nonharmonic control for BVI noise reduction in electrically controlled rotors is carried out. According to the mechanism of the BVI in electrically controlled rotors, the second quadrant flap nonharmonic control is used to reduce the advancing side BVI noise, and the effects of different control waveforms and amplitudes on the peak value and directivity of the BVI noise of the sample electrically controlled rotors are analyzed to reveal the noise reduction mechanism of flap nonharmonic control. Subsequently, the effect of the third quadrant flap nonharmonic control on BVI noise on the retreating side of the sample electrically controlled rotors is investigated. The results show that flap nonharmonic control has little effect on miss distance and that it controls BVI noise mainly by reducing the wake vortex strength on the advancing and retreating sides, which may lead to an increase in rotor noise in other regions; the noise reduction effect of flap nonharmonic control for different blade preindex angles indicates that suitable preindex angles coupled with flap nonharmonic control help optimally reduce noise.

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Section: Results and Analysismentioning

confidence: 99%

Section: Results and Analysismentioning

confidence: 99%

Section: Computational Model Of Aerodynamic Noise In the Bvimentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Nonharmonic Control of the Blade-Vortex Interaction Noise of Electrically Controlled Rotor

Ke-wei

et al. 2022

International Journal of Aerospace Engineering

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“…The effect of flap deflection on the wake and vortex circulation distribution at the blade boundaries was considered in his work. Another aerodynamic model of ACF rotor was proposed by Su [57,58] based on the viscous vortex particle method and a lifting surface model recently.…”

Section: Introductionmentioning

confidence: 99%

Numerical and experimental analysis on the helicopter rotor dynamic load controlled by the actively trailing edge flap

Zhou

Huang

Tian

et al. 2022

Smart Mater. Struct.

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Reducing the rotor dynamic load is an important issue to improve the performance and reliability of a helicopter. The control mechanism of the actively controlled flap on the rotor dynamic load is numerically and experimentally investigated by a 3-blade helicopter rotor in this paper. In the aero-elastic numerical approach, the complex motion of the rotor such as the stretching, bending, torsion and pitching of the blade including the deflection of the actively controlled flap (ACF) are all taken into consideration in the structural formulation. The aerodynamic solution adopted the vortex lattice method combining with the free wake model, in which the influence of ACF on the free wake and the aerodynamic load on the blade is taken into account as well. While the experimental method of measuring hub loads and acoustic was accomplished by a rotor rig in a wind tunnel. The result shows that the 3/rev ACF actuation can reduce the $3\omega$ hub load by more than 50\% at maximum, which is significantly better than the 4/rev control. While 4/rev has greater potential to reduce BVI loads than 3/rev with $\mu=0.15$. Further mechanistic analysis shows that by changing the phase difference between the dynamic load on the flap and the rest of the blade, the peak load on the whole blade can be improved, thus achieving effective control of the hub dynamic load, the flap reaches the minimum angle of attack at 90°-100° azimuth under best control condition; when the BVI load is perfectly controlled, the flap reaches the minimum angle of attack at 140° azimuth, and by changing the circulation of the wake, the intensity of blade vortex interaction in the advancing side is improved. Moreover, an interesting finding in the optimal control of noise and vibration is that an overlap point exist on the motion patterns of the flap with different frequencies.

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Open-Loop Simulation of Active Vibration Control of Electrically Controlled Rotor

Ke-wei

et al. 2023

Machines

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An electrically controlled rotor (ECR), also known as a swashplateless rotor, is an active rotor system that reduces the vibration load of the rotor through active control while achieving primary control by using a trailing edge flap system instead of a swashplate. In this study, the control effect of a 2Ω higher-order harmonic input on the vibration load of an ECR is investigated. First, an analytical aeroelastic model of the ECR is established based on Hamilton’s principle and an unsteady aerodynamic model with a flapped airfoil. On this basis, the use of higher-order harmonic flap control to reduce the vibration load of the ECR is investigated. The effect of the 2Ω higher-order harmonic flap control on the 2Ω vibration load of the example ECR is analyzed by sweeping the amplitude and phase of the higher-order harmonic flap control. The effect of higher-order harmonic flap control on the primary control of the ECR is also analyzed. The results show that the 2Ω higher-order flap deflection has the most significant control effect on the 2Ω vertical vibration load of the hub, that there is coupling between the higher-order flap deflection and the primary control of the ECR, and that the higher-order flap deflection disrupts the original equilibrium of the ECR.

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Electrically Controlled Rotor Blade Vortex Interaction Airloads and Noise Analysis Using Viscous Vortex Particle Method

Cited by 3 publications

References 32 publications

Nonharmonic Control of the Blade-Vortex Interaction Noise of Electrically Controlled Rotor

Nonharmonic Control of the Blade-Vortex Interaction Noise of Electrically Controlled Rotor

Numerical and experimental analysis on the helicopter rotor dynamic load controlled by the actively trailing edge flap

Open-Loop Simulation of Active Vibration Control of Electrically Controlled Rotor

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