Calculation of Rotor Blade-Vortex Interaction Airloads Using a Multiple-Trailer Free-Wake Model

Lim, Joon W.; Yu, Yung H.; Johnson, Wayne

doi:10.2514/1.130

Cited by 6 publications

(12 citation statements)

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“…It is noted that the heavier blades exhibit higher peak-topeak deflections for the case with HART II blades [20], which have similar dynamic characteristics with HART I blades. For MN and MV cases, the predicted results by Lim et al [9] show locally good agreements with the measured data, but the waveforms are biased to the advancing side (MN) or to the retreating side (MV), resulting in different waveforms with the measured blade responses. It should be mentioned that Lim et al [9] used slightly different set of structural properties where the DEI data were used for the blade uniform section while HART II blade properties were adopted in the root section.…”

Section: Trim and Blade Motionssupporting

confidence: 56%

“…The correlation of the present elastic twist predictions, against the measured data as well as predicted results by Lim et al [9], is presented in Figure 12 for the three test cases, respectively. The present predictions show good agreements with the measured data in terms of both magnitudes and phases, with a slight under-estimation of the peak-topeak values for MN and MV cases.…”

Section: Trim and Blade Motionsmentioning

confidence: 89%

“…Figure 11 shows the time domain response of the elastic flap displacements at the blade tip, obtained between the present predictions and the wind tunnel measurements for BL, MN, MV cases, respectively. Results by Lim et al [9] are presented for comparison. As is seen, the present predictions generally underestimate the peak-to-peak values against the measured data.…”

Section: Trim and Blade Motionsmentioning

confidence: 99%

“…Despite the fact that HART I test was completed much earlier than HART II and valuable sources of high precision data were provided, the published efforts associated with HART I are significantly less in volume, as compared with HART II [4]. The representative ones of HART I are Tung et al [5], Beaumier and Spiegel [6], Brooks et al [7], Lim et al [8][9], and Yeo and Johnson [10][11]. Most of the research focused on correlating the airloads and vortex wakes against the measured data.…”

Section: Introductionmentioning

confidence: 99%

“…This suggests uncertainty in the DEI blade property set and there is a need to supply reliable HART I blade properties data which can only be achieved by a careful measurement process. Furthermore, it has been known that up to four different sets of blade property data for HART I are in use [5][6][7][8][9][10][11] and there is a clear need for unified version of the blade properties.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Evaluation of Rotor Structural and Aerodynamic Loads Using Measured Blade Properties

Jung

You²,

Lau

et al. 2013

J Am Helicopter Soc

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The structural properties of Higher harmonic Aeroacoustic Rotor Test (HART I) blades have been measured using the original set of blades tested in the wind tunnel in 1994. A comprehensive rotor dynamics analysis is performed to address the effect of the measured blade properties on airloads, blade motions, and structural loads of the rotor. The measurements include bending and torsion stiffness, geometric offsets, and mass and inertia properties of the blade. The measured properties are correlated against the estimated values obtained initially by the manufacturer of the blades. The previously estimated blade properties showed consistently higher stiffnesses, up to 30% for the flap bending in the blade inboard root section. The measured offset between the center of gravity and the elastic axis is larger by about 5% chord length, as compared with the estimated value. The comprehensive rotor dynamics analysis was carried out using the measured blade property set for HART I rotor with and without HHC (Higher Harmonic Control) pitch inputs. A significant improvement on blade motions and structural loads is obtained with the measured blade properties.

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Section: Trim and Blade Motionssupporting

confidence: 56%

Section: Trim and Blade Motionsmentioning

confidence: 89%

Section: Trim and Blade Motionsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Evaluation of Rotor Structural and Aerodynamic Loads Using Measured Blade Properties

Jung

You²,

Lau

et al. 2013

J Am Helicopter Soc

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Aeroelastic response of helicopter rotors using a 3D unsteady aerodynamic solver

Gennaretti

Bernardini

2006

Aeronaut. j.

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The prediction of blade deflections and vibratory hub loads concerning helicopter main rotors in forward flight is the objective of this work. They are determined by using an aeroelastic model derived through the coupling between a nonlinear blade structural model and a boundary integral equation solver for three-dimensional, unsteady, potential aerodynamics. The Galerkin method is used for the spatial integration, whereas the periodic blade response is determined by a harmonic balance approach. This aeroelastic model yields a unified approach for aeroelastic response and blade pressure prediction that may be used for aeroacoustic purposes, with the possibility of including effects from both blade-vortex interaction and multiple-body aerodynamic interaction. Quasi-steady aerodynamic models with wake-inflow from the three-dimensional aerodynamic solver are also applied, in order to perform a comparative study. Numerical results show the capability of the aeroelastic tool to evaluate blade response and vibratory hub loads for a helicopter main rotor in level flight conditions, and examine the sensitivity of the predictions on the aerodynamics model used.

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Numerical analysis of propeller-excited plate vibrations

et al. 2021

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Intense vibrations excited by a propeller worsen the structural reliability of a ship. In this study, a ship hull is modeled as a simple rectangular plate to study propeller excitation vibrations. The interaction between a rectangular plate and propeller is studied, considering the fluid–structure interaction. The turbulence in the flow field is modeled by detached eddy simulations. The results show that in the propeller wake, the pressure fluctuations corresponding to the blade passing frequency (BPF) of the propeller are dominant. In the flow field near the plate, the pressure fluctuations corresponding to the natural frequencies of the plate are dominant. The plate vibrations under a propeller exciting force contain vibrations corresponding to the BPF of the propeller and natural frequencies of the plate. The vibrations of the plate can be divided into vibrations caused by propeller rotation and natural vibrations. The excitation force from the propeller changes the mode shapes of the plate. The vibrations excited by the propeller wake decrease as the distance between the propeller and the plate increases.

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Calculation of Rotor Blade-Vortex Interaction Airloads Using a Multiple-Trailer Free-Wake Model

Cited by 6 publications

References 0 publications

Evaluation of Rotor Structural and Aerodynamic Loads Using Measured Blade Properties

Evaluation of Rotor Structural and Aerodynamic Loads Using Measured Blade Properties

Aeroelastic response of helicopter rotors using a 3D unsteady aerodynamic solver

Numerical analysis of propeller-excited plate vibrations

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