The HART II test – measurement of helicopter rotor wakes

Wall, Berend G. van der; Burley, Casey L.; Yu, Yung; Richard, Hugues; Pengel, K.; Beaumier, Philippe

doi:10.1016/j.ast.2004.01.001

Cited by 58 publications

(64 citation statements)

References 1 publication

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“…Same waves are repeated at an interval of 90 in the calculation because all four blades are identical, but they differed in the experiment because the physical properties of the four blades were different; pressure sensors were embedded in only two blades and these blades moved differently, causing a different BVI noise for each blade. 22) At each BVI peak, there was a difference in peak level between the calculation with elastic deformation and the experiment; the sound pressure is overestimated in the calculation rather like the amplitude of blade loading in Fig. 11.…”

Section: Bvi Between Elastically Deforming Rotor Bladesmentioning

confidence: 99%

“…For the purpose of this model, we use the time history data of blade deformation measured in the HART II project experiments. 21,22) This project data includes information about ''flapping'' (bending perpendicularly with respect to blade surface), ''lead-lag'' (forward or backward bending along blade surface), and ''torsion'' (twisting around quarter chord of blade). These data are available at interval both in space (at eighteen spanwise position) and in time (at every 15 degrees of azimuth angle), and need to be interpolated for our calculation, which requires the continuous blade position both in time and space.…”

Section: Bvi Between Elastically Deforming Rotor Bladesmentioning

confidence: 99%

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Efficient Prediction of Helicopter BVI Noise under Different Conditions of Wake and Blade Deformation

Inada¹,

Yang²,

Iwanaga³

et al. 2008

Trans. Japan Soc. Aero. S Sci.

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Predictions of helicopter BVI noise using three-dimensional Euler code with a single blade grid are conducted under three different conditions: BVI noise caused by (1) interaction between rotating blades and vortex shed from fixed wing vortex generator, (2) interaction between rotating blades and tip vortices shed from preceding blades, and (3) interaction between rotating blades with elastic deformation and shed tip vortices. In the CFD calculation, the Field Velocity Approach (FVA) and Scully's vortex model are used to import the wake information into the calculation grid and to determine the induced velocity made by tip vortices, respectively (cases 1-3). Beddoes generalized wake model is used to prescribe the tip vortices position in the wake (cases 2 and 3). Information about blade elastic deformation is imported from HART II project experimental data into the calculation (case 3). Acoustic analyses based on Ffowcs-Williams and Hawkings (FW-H) equation are conducted subsequently in each case. The results from the calculations show good agreement with experiments in all three cases, indicating that application of FVA, Scully's model, and Beddoes generalized wake model is effective for BVI noise prediction in this study, which is intended for low calculation cost using a single blade grid. Also, use of blade elastic deformation data in the calculation shows marked improvement in calculation precision. Consequently, the method used in this study can predict BVI noise under various conditions of wake or blade deformation with acceptable precision and low calculation cost.

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Section: Bvi Between Elastically Deforming Rotor Bladesmentioning

confidence: 99%

Section: Bvi Between Elastically Deforming Rotor Bladesmentioning

confidence: 99%

Efficient Prediction of Helicopter BVI Noise under Different Conditions of Wake and Blade Deformation

Inada¹,

Yang²,

Iwanaga³

et al. 2008

Trans. Japan Soc. Aero. S Sci.

View full text Add to dashboard Cite

show abstract

“…One way to achieve this is to examine the pressure distribution at the blade tip. There has been considerable research involving pressure measurements on rotor blades [1][2] . These measurements, however, typically lack the resolution to capture phenomena such as the nascent tip vortex or dynamic stall.…”

Section: Introductionmentioning

confidence: 99%

Blade Tip Pressure Measurements Using Pressure-Sensitive Paint

Wong¹,

Watkins²,

Goodman³

et al. 2018

j am helicopter soc

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This paper discusses the application of pressure sensitive paint using laser-based excitation for measurement of the upper surface pressure distribution on the tips of rotor blades in hover and simulated forward flight. The testing was conducted in the Rotor Test Cell and the 14-by 22-ft Subsonic Tunnel at the NASA Langley Research Center on the General Rotor Model System (GRMS) test stand. The Mach-scaled rotor contained three chordwise rows of dynamic pressure transducers for comparison with PSP measurements. The rotor had an 11 ft 1 in. diameter, 5.45 in. main chord and a swept, tapered tip. Three thrust conditions were examined in hover, C T = 0.004, 0.006 and 0.008. In forward flight, an additional thrust condition, C T = 0.010 was also examined. All four thrust conditions in forward flight were conducted at an advance ratio of 0.35.

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“…In addition, it is superior to other non-contact methods, such as those using laser displacement sensors (LDS), because it is capable of a fullfield measurement with the use of only a single set of sensors. Owing to these advantages, its application ranges from the deflection estimation of laboratory test structure model [3,4] to various maneuvering structures such as aircraft wings [5][6][7], rotor blades [8][9][10] and civil infrastructures [11][12][13][14].…”

Section: Introductionmentioning

confidence: 99%

Performance evaluation method of homogeneous stereo camera system for full-field structural deformation estimation

Yun¹,

Kim²,

Han³

et al. 2015

International Journal of Aeronautical and Space Sciences

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This study presents how we can evaluate stereo camera systems for the structural deformation monitoring. A stereo camera system, consisting of a set of stereo cameras and reflective markers attached on the structure, is introduced for the measurement and the stereo pattern recognition (SPR) method is utilized for the full-field structural deformation estimation. Performance of this measurement system depends on many parameters including types and specifications of the cameras, locations and orientations of them, and sizes and positions of markers; it is difficult to experimentally identify the effects of each parameter on the measurement performance. In this study, a simulation framework for evaluating performance of the stereo camera systems with various parameters has been developed. The maximum normalized root-mean-square (RMS) error is defined as a representative index of stereo camera system performance. A plate structure is chosen for an introductory example. Its several modal harmonic vibrations are generated and estimated in the simulation framework. Two cases of simulations are conducted to see the effects of camera locations and the resolutions of the cameras. An experimental validation is carried out for a few selected cases from the simulations. Using the simultaneous laser displacement sensor (LDS) measurements as the reference, the measurement errors are obtained and compared with the simulations.

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The HART II test – measurement of helicopter rotor wakes

Cited by 58 publications

References 1 publication

Efficient Prediction of Helicopter BVI Noise under Different Conditions of Wake and Blade Deformation

Efficient Prediction of Helicopter BVI Noise under Different Conditions of Wake and Blade Deformation

Blade Tip Pressure Measurements Using Pressure-Sensitive Paint

Performance evaluation method of homogeneous stereo camera system for full-field structural deformation estimation

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