An Efficient Approach for the Simulation and On-Blade Control of Helicopter Noise and the Impact on Vibration

Chia, Miang H.; Padthe, Ashwani K.; Duraisamy, Karthik; Friedmann, Peretz P.

doi:10.4050/jahs.62.042004

Cited by 5 publications

(12 citation statements)

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“…It was found in [16] that a microphone located on the left boom position provided the best feedback for closed-loop in-plane noise reduction. The feedback microphone location is illustrated in Fig.…”

Section: Resultsmentioning

confidence: 99%

“…In the adaptive HHC algorithm, the sensitivity matrix T is updated recursively, based on the input and output history, using a leastsquares methods. A detailed description of this version is provided in [35], and the details of its implementation for active in-plane noise control are provided in [16].…”

Section: Higher Harmonic Control Algorithmmentioning

confidence: 99%

“…The AVINOR/HELINOIR code, employing a straight blade modeled using the global Galerkin method, has been validated against experimental data [16] obtained in two major wind-tunnel tests: 1) the Higher-Harmonic-Control Aeroacoustic Rotor Test (HART) [36], and 2) the Boeing-SMART rotor wind-tunnel test conducted in the 40 × 80 ft wind tunnel at NASA Ames Research Center [37].…”

Section: Validation Studiesmentioning

confidence: 99%

“…6, and it is evident that the pressure history is predicted well, capturing the peak-to-peak amplitude accurately. Further details of the code validation and verification can be found in [16].…”

Section: Validation Studiesmentioning

confidence: 99%

“…The HELINOIR code combined with the Active Vibration and Noise Reduction (AVINOR) comprehensive rotorcraft analysis code [15] is well suited for such a study. The AVINOR code coupled with HELINOIR has been validated for out-of-plane BVI and in-plane noise prediction and verified for active in-plane noise control using an active flap [16]. The AVINOR/HELINOIR code suite is described with additional details in the current study to examine passive noise reduction using modified blade-tip planforms.…”

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confidence: 99%

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Active and Passive Helicopter Noise Reduction Using the AVINOR/HELINOIR Code Suite

Chia

Duraisamy

Padthe

et al. 2018

Journal of Aircraft

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A suite of computational tools capable of predicting in-plane low-frequency rotorcraft noise and its control using blade-tip geometry modifications is developed. The combined code, consisting of AVINOR, a comprehensive rotorcraft analysis code, and an acoustic code called HELINOIR, is first validated against wind-tunnel tests and subsequently verified by comparing with computational results. Three rotor configurations resembling the Messerschmitt-Bölkow-Blohm BO105 with a tip sweep, dihedral, and anhedral were simulated for level flight at a moderate advance ratio. The impact of passive blade geometry modification on in-plane noise and vibration is studied and compared to the in-plane noise reduction obtained using a single 20% chord active plain trailing-edge flap with a feedback microphone on the left boom. Active control, which is implemented using an adaptive higher harmonic control algorithm, reduces in-plane low-frequency sound pressure levels below the horizon by up to 6 dB, but there is an increase in vibratory loads. The tip dihedral reduces low-frequency sound pressure level by up to 2 dB without a vibratory load penalty, but there is an increase in the midfrequency sound pressure levels. The tip sweep and tip anhedral increase in-plane low-frequency sound pressure level below the horizon. There is a general tradeoff associated with in-plane low-frequency sound pressure level reduction, vibration performance, and midfrequency sound pressure level.

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Section: Resultsmentioning

confidence: 99%

Section: Higher Harmonic Control Algorithmmentioning

confidence: 99%

Section: Validation Studiesmentioning

confidence: 99%

Section: Validation Studiesmentioning

confidence: 99%

mentioning

confidence: 99%

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Active and Passive Helicopter Noise Reduction Using the AVINOR/HELINOIR Code Suite

Chia

Duraisamy

Padthe

et al. 2018

Journal of Aircraft

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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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Numerical and Experimental Investigation of a Single-Axis Parallel Active Vibration Mount for Helicopter Seats Using Vibration Standards

Fereidooni

Graham

Chen

et al. 2020

Journal of Dynamic Systems, Measurement, and Control

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This paper presents the experimental and numerical investigation of a single-axis replicate of a patented multi-axis active vibration isolation seat mount. Following the design of the multi-axis system, this single axis vibration isolation mount uses a flexible elastomer support placed in parallel with an electromagnetic actuator. This mount is designed to reduce the N/rev harmonic vibration of a helicopter using a filtered-X least mean square (FXLMS)-based controller. To improve the efficiency of the FXLMS controller for this application, the ISO-2631-1 Wk filter is added. Employing this modified controller, the experimental setup is tested using a payload mass representative of a 95th percentile pilot. The experimental results confirm the effectiveness of the proposed design in canceling the unwanted helicopter vibration, where the active mount effectively reduces the vibration representative of a Bell-412 helicopter by 69.37% (−10.28 dB, g-rms). In order to develop a better understanding of the problem, the system is also modeled from first principles in simulink. The comparison between the nonlinear numerical model and the experimental results demonstrates a good agreement between the two approaches. Moreover, it is shown that the addition of the ISO-2631-1 Wk filter improves the transient performance of the FXLMS controller for the given helicopter vibration profile.

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An Efficient Approach for the Simulation and On-Blade Control of Helicopter Noise and the Impact on Vibration

Cited by 5 publications

References 0 publications

Active and Passive Helicopter Noise Reduction Using the AVINOR/HELINOIR Code Suite

Active and Passive Helicopter Noise Reduction Using the AVINOR/HELINOIR Code Suite

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

Numerical and Experimental Investigation of a Single-Axis Parallel Active Vibration Mount for Helicopter Seats Using Vibration Standards

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