Aerodynamics and acoustics of rotor blade-vortex interactions

Yu, Yung H.; Tung, Chee; Gallman, Judith M.; Schultz, Klaus J.; Wall, Berend van der; Spiegel, P.; Michea, Bertrand

doi:10.2514/3.46825

Cited by 40 publications

(8 citation statements)

References 4 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…where β is logical variable (β = 1 N-S solver, β = 0 Euler solver). Previous researches have shown that viscous effects have a negligible influence [9,15] on aerodynamic flow filed of BVI and the Euler equations are most effective for increasing computational efficiency. Therefore, the Euler model of equation ( 1) is chosen in the present study.…”

Section: Non-linear Aerodynamicsmentioning

confidence: 99%

“…Rotor wake characteristics play an important role in determining the nature of BVI. Over the past years, many different hybrid computational codes with a combination of computational fluid dynamics (CFD) and free wake analysis have been developed for BVI loading prediction [8][9][10]. The results from these works show that the quality of the correlation with experimental data is dependent on the wake structure/geometry from the comprehensive analytic model of rotor aerodynamics.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

An Analytical Study of Parametric Effects on Rotor—Vortex Interaction Noise

Shi

Zhao

2011

Proceedings of the Institution of Mechanical Engineers, Part G:

View full text Add to dashboard Cite

A numerical method for modelling the aerodynamic interaction between rotor blades and an independently generated vortex is developed. In this method, the Navier—Stokes/Euler equations are adopted for capturing the features of rotor blade—vortex interaction (BVI) flow and the overset grids technique is used for multi-zone solution. To incorporate the effects of the vortex in the solution, a generalized grid-velocity approach is presented to simplify the computations. The acoustic prediction is based on the well-known Ffowcs Williams-Hawkings (FW-H) equation for acoustic pressure. By this method developed, a parametric study is performed to examine the effects of the vortex strength, miss-distance, core-radius, oblique interaction, and interaction angle in a blade-shaft plane on BVI noise. The results indicate that the increase in miss-distance, core-radius, obliqueness of interaction, or interaction angle in a blade-shaft plane is an effective approach to reduce BVI noise, makes the BVI noise less impulsive (lower high harmonic content in noise energy) and increases the high noise encompassed area. However, the decrease in vortex strength changes only the magnitude of noise, not its distribution in different harmonics. The research also indicates that oblique interaction in a rotor plane has a significant effect on radiation directionality, while other parameters show little impact on it.

show abstract

Section: Non-linear Aerodynamicsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

An Analytical Study of Parametric Effects on Rotor—Vortex Interaction Noise

Shi

Zhao

2011

Proceedings of the Institution of Mechanical Engineers, Part G:

View full text Add to dashboard Cite

show abstract

“…The 10014 test case under BVI state [32,33] The flow solver is run for four revolutions with 1440 steps per revolution in the azimuthal direction during the CFD computation, that is, the time step corresponds to the 0.25 °azimuthal angle. The CFD codes run on a standard PC with an 8-core Intel Core i7-7700 CPU (3.60 GHz) and 9 International Journal of Aerospace Engineering 32.0 GB of RAM [20,21].…”

Section: Resultsmentioning

confidence: 99%

Numerical Investigation of an Unsteady Blade Surface Blowing Method to Reduce Rotor Blade-Vortex Interaction Noise

Sun

Shi

2022

International Journal of Aerospace Engineering

View full text Add to dashboard Cite

This paper presents a numerical investigation of unsteady surface blowing using periodic variations of jet velocity with azimuthal angle to reduce helicopter rotor blade-vortex interaction (BVI) noise. The unsteady blowing is modeled as the mass flow outlet boundary condition of time-varying jet velocity on the blade surface grid using computational fluid dynamics. The same high-resolution overset grid system and flow/noise solver are used to perform a detailed flow field simulation and noise prediction for the nonblowing baseline case and the steady/unsteady blowing cases under the rotor BVI condition, and a grid convergence study for the steady and unsteady blowing cases is carried out. The BVI noise reduction and rotor thrust coefficient results of the unsteady blowing method and the previously published steady blowing with constant jet velocity are then compared. The noise reduction level of unsteady blowing is approximately equivalent to that of steady blowing (noise reduction is more than 3 dB). However, the loss in rotor thrust coefficient caused by unsteady blowing (3.3%) is only half of that by steady blowing (6.3%); the air mass cost by unsteady blowing is only 63.7% of that by steady blowing per rotation revolution. The results show that unsteady blowing can effectively reduce BVI noise with lower cost and less thrust loss.

show abstract

“…It can be seen that results of this paper demonstrate good agreement with those of Baeder. Figure 4 shows the experimental sound pressure of the AH-1/OLS [32] single rotor, compared with the calculated results of this paper. The state is Matip = 0.664, μ = 0.164, which has obvious blade vortex interaction (BVI).…”

Section: Validation Casesmentioning

confidence: 96%

Investigation on Aerodynamic Noise Characteristics of Coaxial Rotor in Hover

Wang

Jiang

et al. 2022

Applied Sciences

View full text Add to dashboard Cite

A numerical method based on Reynolds Averaged Navier–Stokes (RANS) equations and a high-efficiency trim model is developed to simulate the aerodynamics of a coaxial rotor. Farassat 1A equations are used for the prediction of thickness and loading noise. Hover cases of different thrust coefficients with torque balance are conducted. The sound pressure history of different observation points positioned below the rotor disk plane is analyzed. Results indicate that the special noise characteristics of the coaxial rotor are mainly caused by the noise superposition of the twin rotors and the unsteady loads of aerodynamic interaction. A new kind of impulsive loading noise is induced by the blade-meeting interaction. In contract to the single rotor, the loading noise of a coaxial rotor has a much larger sound pressure level in the high-frequency band. The loading noise is obviously enhanced around the blade-meeting azimuths. The maximum noise of the coaxial rotor is located immediately below the rotor disk center, while for the single rotor, it is the minimum location.

show abstract

Aerodynamics and acoustics of rotor blade-vortex interactions

Cited by 40 publications

References 4 publications

An Analytical Study of Parametric Effects on Rotor—Vortex Interaction Noise

An Analytical Study of Parametric Effects on Rotor—Vortex Interaction Noise

Numerical Investigation of an Unsteady Blade Surface Blowing Method to Reduce Rotor Blade-Vortex Interaction Noise

Investigation on Aerodynamic Noise Characteristics of Coaxial Rotor in Hover

Contact Info

Product

Resources

About