Aeroelastic and aeroacoustic modelling of rotorcraft

Opoku, Daniel

doi:10.22215/etd/2002-05227

Cited by 13 publications

(28 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…(2.12)). On thin lifting bodies, SmartRotor also corrects the potential load distribution to account for the leading edge suction force [42], [51].…”

Section: Smartrotor Aerodynamic Componentmentioning

confidence: 99%

Numerical Predictions of Propeller-Wing Interaction Induced Noise in Cruise and Off-Design Conditions

Boots¹

View full text Add to dashboard Cite

Using numerical methods, the aeroacoustic field induced by the interaction of a 4-bladed NASA SR-2 propeller and its wake with a wing is investigated under cruise conditions (Mach 0.6). The SmartRotor code, a coupled vortex particle and panel method, which is integrated with an acoustic solver based on the Farassat 1A formulation of the Ffowcs-Williams Hawkings equation, was used. Three main areas were investigated: the effect of propeller tip geometry on the propeller's wake and blade tip vortex; the effect of integrating a wing in the tractor configuration, including the effect of its position, and wing local leading edge sweep; and the effect of operating the combined wing/propeller system in off-design conditions such as low forward speed or in non-axial inflow.It was discovered that tip sweep is effective at reducing propeller tip vortex strength with no adverse effect on noise. Modifying tip dihedral was found to always increase tip vortex strength. Integrating a wing in the wake of the propeller increased the broadband noise generated, but had little effect on harmonic noise. The downstream position of the wing was found to not affect noise while vertical offset from the propeller axis increased noise. The most important discovery was that applying local leading edge sweep to the wing in the region of the propeller's wake decreases noise proportionally to the change in the angle between the helical tip vortex and the wing's leading edge. These noise reductions were on the order of up to 1.3 dB for overall sound pressure level, and 7.5 dB at the blade passage frequency.iii Acknowledgements First on the list of many people to thank must be my supervisor, Professor Daniel Feszty. His constant enthusiasm and support of my work was invaluable whenever simulations weren't working or results seemed less than reasonable. At the same time, his way of providing guidance while allowing me to choose the direction of my research allowed me to follow up on interesting results and truly take ownership of this work. For this and so much more, thank you.

show abstract

“…(2.12)). On thin lifting bodies, SmartRotor also corrects the potential load distribution to account for the leading edge suction force [42], [51].…”

Section: Smartrotor Aerodynamic Componentmentioning

confidence: 99%

Numerical Predictions of Propeller-Wing Interaction Induced Noise in Cruise and Off-Design Conditions

Boots¹

View full text Add to dashboard Cite

show abstract

“…The FW-H equation has been successfully applied to a wide variety of problems, including propellers, helicopter rotors, and HAWTs [28][29][30][31]. For surfaces moving at subsonic speeds through a medium at rest, solutions of the FW-H equation called Formulations 1 and 1A were derived by Farassat and Succi are commonly used [27,28,32].…”

Section: Aeroacousticsmentioning

confidence: 99%

“…Vortex lattice methods, such as the work by Dixon [42], and vortex particle methods with cut-off lengths are two possible solutions. For example, the Generalized Unsteady Vortex Particle method (GENUVP) developed at the National Technical University of Athens has successfully used a surface panel method and vortex particle wake model to predict the aerodynamics and aeroacoustics of helicopter rotor blades [30].…”

Section: Aerodynamicsmentioning

confidence: 99%

“…The program developed in the present work can represent the far-wake as uniformstrength doublet panels, and include their perturbation velocity field into the solution using a Neumann BC in order to investigate their appropriateness for VAWT applica- The approach taken to modelling the far-wake for the majority of this work is to represent it using vortex particles. This approach has been used successfully in conjunction with panel methods to predict the aerodynamics of rotorcraft [30], and has well-known optimization schemes. The details of this approach may be found in App.…”

Section: Far-wake Representation Using Vortex Particlesmentioning

confidence: 99%

“…The structural vibrations will contribute an additional fluctuation in the velocity distribution over the rotor blades which will contribute to the thickness perturbation pressure. A subgrid approximation, as described in detail in [30], considers the rotor blades to have different scaling levels of discretization, and treats the aerodynamic effects of panels at a point far away from the panels as a group rather than individual panels.…”

Section: Recommendationsmentioning

confidence: 99%

See 2 more Smart Citations

Prediction and Assessment of the Surface-Based Aeroacoustics of Vertical-Axis Wind Turbines

Williams¹

View full text Add to dashboard Cite

Aerodynamic and aeroacoustic prediction tools are developed for rigid rotor blades in unsteady motion to provide insight into the aeroacoustics of vertical-axis wind turbine rotor blades. The aerodynamic component uses a subsonic unsteady inviscid panel method over the surface of the rotor blades to predict the unsteady pressure distribution over the surface, with vortex particles being shed from the blades to represent their freely-convecting wake. Using the velocity and pressure distributions over the rotor blades, the aeroacoustic component employs a non-penetrable version of Formulation 1C of the Ffowcs Williams-Hawkings equation to predict the noise from surface-based acoustic sources called thickness and loading noise. The prediction tools are compared to accepted results for fundamental test cases and vertical-axis wind turbines before being used to investigate the aerodynamics and acoustic noise of vertical-axis wind turbine rotors. Investigations into the effects of the blade geometry, the geometric scale of the rotor, the number of rotor blades, and the tip speed ratio of the rotor on the acoustic field are presented. The acoustic results are expected to under-predict the total acoustic noise of vertical-axis wind turbines.iii

show abstract

Mid-fidelity approach to aerodynamic simulations of unconventional VTOL aircraft configurations

Tugnoli

Montagnani

Syal

et al. 2021

Aerospace Science and Technology

View full text Add to dashboard Cite

Aeroelastic and aeroacoustic modelling of rotorcraft

Cited by 13 publications

References 0 publications

Numerical Predictions of Propeller-Wing Interaction Induced Noise in Cruise and Off-Design Conditions

Numerical Predictions of Propeller-Wing Interaction Induced Noise in Cruise and Off-Design Conditions

Prediction and Assessment of the Surface-Based Aeroacoustics of Vertical-Axis Wind Turbines

Mid-fidelity approach to aerodynamic simulations of unconventional VTOL aircraft configurations

Contact Info

Product

Resources

About