Numerical research on the rotor “super blade/vortex interaction noise” generation mechanism in helicopter roll maneuver state

Physics of Fluids, Journal Year: 2025, Volume and Issue: 37(1)

Published: Jan. 1, 2025

To explore the evolution law of rotor vortex and aeroacoustic characteristics during helicopter roll maneuver flight, numerical simulations were conducted in different rates based on high-precision computational fluid dynamics method Ffowcs Williams-Hawkings equation. Initially, we verified collective pitch increased test blade/vortex interaction (BVI) cases. The comparison results show that constructed can capture aerodynamic transient maneuvering states has reliable predictive capability for BVI noise. Then, analyses right was performed. It found state, multiple vortices merge develop into a higher-intensity “supervortex system” near 75° azimuth angle, triggering “superblade/vortex noise” (Super-BVI) upon collision with subsequent blade, maximum increase overall sound pressure level (OASPL) approximately 16 dB. Next, carried out left rates, it (pmax) OASPL (OASPLmax) have linear logarithmic relationships rate, respectively. This holds both left- right-roll states. Finally, four cases specific angles comprehensive studies. maneuvers intensify strength rolling side while weakening other side, which is closely linked to formation mechanism “Super-BVI noise.”

Language: Английский

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Designing a Probable Engine for Future Supersonic Transport Aircraft

International Journal of Engineering and Advanced Technology, Journal Year: 2025, Volume and Issue: 14(3), P. 33 - 39

Published: Feb. 20, 2025

Supersonic transport (SST) is poised to revolutionize the aviation industry once again, offering potential for significantly reduced travel times across transcontinental and transoceanic routes. This paper delves into key engine design elements next-generation SST aircraft, focusing on critical areas such as fuel efficiency, environmental sustainability, noise reduction. With a particular emphasis low-bypass turbofan engines, variable cycle technology, afterburner integration, this provides comprehensive analysis of technological advancements necessary address challenges that previously plagued supersonic transport, high consumption impact earlier designs like Concorde [1]. The also explores role alternative fuels—namely, sustainable (SAF) liquid hydrogen—and their implications future high-speed aviation. Through computational modeling materials analysis, proposes conceptual model balances performance, regulatory compliance. Areas research, particularly in abatement thermodynamic are outlined.

Language: Английский

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Multilayer stackable grouped acoustic metamaterial with optional sound absorption performance

Journal of Applied Physics, Journal Year: 2025, Volume and Issue: 137(12)

Published: March 24, 2025

The control of noise pollution in the low-frequency domain with various spectrum ranges requires development a novel tunable sound absorbing material, and multilayer stackable grouped acoustic metamaterial (MSG-AM) is proposed this research to obtain optimal reduction effect while minimizing occupied space. MSG-AM includes four layers eight Helmholtz resonators each layer divided into three groups, total 32 different are connected parallel. absorption property optimized by joint simulation finite element particle swarm optimization algorithm, average coefficient (SAC) reaches 0.8609 for first 535–650 Hz, 0.7126 second 782–937 0.9285 third 650–782 0.7615 fourth 435–535 respectively. can be combined flexibly gain desired expected frequency range, sequence multiple critical factor. SAC improved from 0.3696 4 + 1 3 2 0.8726 4, it better put behind front achieve high-frequency domain. mechanism revealed intuitively through distributions thermal power densities, which certify that there exists resonance Fabry–Pérot effects simultaneously. conducive guarantee effective variable noise.

Language: Английский

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Aerodynamic interaction mechanisms in typical wingtip-mounted tractor propeller configurations

Physics of Fluids, Journal Year: 2024, Volume and Issue: 36(12)

Published: Dec. 1, 2024

The wingtip-mounted tractor propeller configuration has been extensively studied due to its great potential for improving wing aerodynamic performance. In the present work, interaction mechanisms in typical configurations are analyzed depth using reformulated vortex particle method. results show that elliptical lift distribution over entire is altered by installation of tip-mounted propeller. coefficient increases with inboard-up rotation and decreases outboard-up rotation. Three key mechanisms, swirl recovery, slipstream distortion, impingement, investigated. recovery mechanism generated rotating positively contributes performance downstream wing. For rotation, propeller-induced downwash reduced increased induced drag. between spanwise velocity wingtip-induced crossflow distortion. At α = 0°, either or on retreating side moved toward axis away from advancing side. With change direction angle attack, geometry exhibits different features. impingement generates time-varying loads at blade passing frequency. tip vortices start bend close leading edge their vorticity increases, then tube begins deform. A higher attack larger fluctuations wing's drag coefficient.

Language: Английский

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Dynamic response of an aeroelastic airfoil within ground effects of flat and wavy surfaces

Physics of Fluids, Journal Year: 2024, Volume and Issue: 36(11)

Published: Nov. 1, 2024

Due to the significant threat posed by waves safety of ground-effect vehicle, a numerical study has been conducted reveal impact patterns on dynamic response an aeroelastic airfoil flying above flat and wavy ground surfaces compared with case in far field. The two degrees freedom equations are coupled governing incompressible flow Reynolds number based chord length Re=6.85×107. is capable pitching plunging motions driven both elastic aerodynamic forces. effects spring stiffness damping ratio flutter explored within effect conditions, respectively. Compared field, exhibits better stability effect. Within surface, as decreases, can be categorized into four different types: static state (U*=5, 6, 7), limit cycle oscillation (U*=8), nonlinear random (U*=9), stall-induced collision (U*=10). When waves, experiences sustained wave excitation, resulting intensified velocity fluctuations increased susceptibility ground. effectiveness mitigating preventing crashes demonstrated for airfoils These findings provide valuable insights risks associated effect, offering implications design wing-in-ground vehicles.

Language: Английский

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Machine-learned flow estimation with sparse data—Exemplified for the rooftop of an unmanned aerial vehicle vertiport

Physics of Fluids, Journal Year: 2024, Volume and Issue: 36(12)

Published: Dec. 1, 2024

We propose a physics-informed data-driven framework for urban wind estimation. This validates and incorporates the Reynolds number independence flows under various working conditions, thus allowing extrapolation conditions far beyond training data. Another key enabler is machine-learned non-dimensionalized manifold from snapshot The velocity field modeled using double encoder–decoder approach. first encoder normalizes data oncoming speed, while second projects this normalized onto isometric feature mapping manifold. decoders reverse process, with k-nearest neighbor performing decoding undoing normalization. coarse-grained by clustering to reduce computational load de- encoding. sensor-based flow estimation based on estimate of speed sensor signal latent variables. proposed exemplified above an unmanned aerial vehicle vertiport. shown generalize well rare not included in original database.

Language: Английский

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