This work investigates the interactions between time-harmonic gusts and a H-Darrieus vertical axis wind turbine (VAWT) using computational fluid dynamics. The motivation is to characterize aerodynamic behavior of VAWTs in gusty urban environments. A systematic study on gust response torque, power output, behaviors VAWT conducted. Results show that significantly impact performance by altering flow field perturbations blade angle attack. Variations amplitude frequency lead changes efficiency...

This work presents a high-efficiency low-noise propeller design for unmanned aerial vehicles. Three different blade configurations are first investigated, using the computational aeroacoustic approach to recognize flow around propellers and noise emissions. The simulation is obtained by an acoustic-wave preserved artificial compressibility method, far-field extrapolated solving Ffowcs-Williams Hawkings equations. Experiments also conducted validate numerical simulations philosophy....

The aeroacoustic characteristics of flying vehicles with pitch-fixed rotors differ from traditional helicopters pitch-controlled rotor blades. Accurate predictions noise are still challenging because many uncertainty factors and unsteadinesses exist. This work investigates the effects rotational speed deviation, rotation fluctuation, blade vibration geometric asymmetry. analysis is based on efficient computation under different working conditions. mean aerodynamic variables computed using...

This study presents a reconstruction of the Gaussian Beam Tracing solution using CUDA, with particular focus on utilisation GPU acceleration as means overcoming performance limitations traditional CPU algorithms in complex acoustic simulations. The algorithm is implemented and optimised NVIDIA RTX A6000 GPU, resulting notable enhancement Summation (GBS) process. In particular, GPU-accelerated GBS demonstrated significant performance, reaching up to 790 times faster city enviroment 188 open...

This study investigates the interaction between a moving monopole point source and vortex, with particular focus on spatiotemporal frequency characteristics of sound field. High-precision numerical simulations are employed to obtain field for different vortex Mach numbers wavelengths. As stationary source, disrupts symmetry field, creating stable beam structures, root mean square scattered pressure proportional number. However, when is in motion, distribution these beams evolves over time,...

This work investigates the aerodynamic and acoustic response of a pitching airfoil subjected to time-harmonic gust flows. A low-dissipation dispersion numerical solver compressible Navier–Stokes equations was developed with kinetic energy preserving flux scheme. The incoming perturbations were introduced via momentum source method. Then, interaction between is subsequently analyzed. In absence gusts, wake composed series vortex pairs convected downstream, while lift drag curves exhibit...

Unmanned aerial vehicles (UAVs) have become an important research topic due to their wide range of applications and potential meet the future air transportation demands. In many configurations UAVs, rotors interact with wake upstream bodies, which is pivotal importance aerodynamic aeroacoustic performance. The studies flow structures noise sources for interacting adjacent bodies at Reynolds numbers lower than 105, operating condition most small are limited. current study, numerical...

The interaction between turbulence and blade leading edges is known to have a significant impact on the aerodynamic aeroacoustic performance of propellers. In addition directly simulating turbulence, synthetic such as momentum source method, has been developed popular method for studying this process in computational fluid dynamics aeroacoustics. However, it found that non-periodic disturbances, although induced velocity field divergence-free, spurious noise may be generated region...

The geometry of the sectional airfoil has a determinative impact on aeroacoustic characteristics propellers. However, there are always slight deviations in practical profiles due to manufacturing tolerance, wear loss, and limitations processing techniques, which can potentially introduce uncertainties measurements. To this end, systematic investigation is conducted benchmark propeller with diameter 217.2 mm several its variants an anechoic wind tunnel. redesigned by modifying shapes varying...

Abstract This paper focuses on the radiation modes and efficiency of propeller tonal noise. The thickness noise loading model propellers has been formulated in spherical coordinates, thereby simplifying numerical evaluation integral source. More importantly, field can be decomposed projected to harmonics, which separate source-observer positions enable an analysis sound structures. Due parity proposed mathematically explain fact that thrusts only produce antisymmetric waves with respect...

This work reports a super-resolution acoustic imaging method that inverses source distribution, strength, and structure in three-dimensional space. The nonlinear coupling process between low-frequency sound field high-frequency plane wave is endowed to break the resolution limit. reconstructed results for different strengths frequencies demonstrate capability of proposed method. show very suitable imaging, which could strengthen analysis tests and, consequently, lead deepened physical...

This study experimentally investigates the potential of using combinations trailing edge serrations and thin porous membrane/velvet structures for turbulent boundary layer noise reduction. The experiments were conducted in an anechoic wind tunnel, with a flat plate model as baseline model. chord-based Reynolds number ranged between 2×105 5×105, layers fully tripped near leading edge. Two different installation methods tested, where serration structure was aligned/misaligned undisturbed wake...

In this paper we present a theoretical model to study sound scattering from flow ducts with semi-infinite lining surface covered by some equally spaced rigid splices, which is of practical importance in the development silent aeroengines. The key contribution our work analytical and rigorous description axial liner splices incorporating Fourier series expansion Wiener–Hopf method. particular, describe periodic variations using that accurately represent layout circumferential direction....

This paper presents an efficient impedance eduction method for grazing flow incidence tube by using a surrogating model along with the Wiener–Hopf method, which enables rapid acoustic predictions and effective eductions over range of parametric values working conditions. The proposed is demonstrated comparing to theoretical results, numerical predictions, experimental measurements, respectively. All demonstrations clearly suggest capability potential solver studies optimizations lining methods.

Vortical gusts are unsteady flow disturbances that can affect the aerodynamic performance and stability of aircraft. Generating realistic vortical in simulations is challenging due to complexity diversity turbulence characteristics. This paper introduces a novel framework for creating using momentum sources. The method manipulate incoming with any desired divergence-free velocity perturbation at location avoid unwanted acoustic waves meanwhile. It starts from linearized incompressible...

Electric vertical and takeoff/landing vehicles for urban aerial mobility have attracted considerable attention in recent years. Some of these are equipped with ducted propellers to improve power efficiency, but the duct may also affect propeller noise generation radiation. This work presents thorough numerical investigations assess importance a short on An analytical model is employed predict emission from an isolated propeller, boundary element method adopted account acoustic scattering...

Traditional sound source localization methods encounter significant challenges in simultaneously locating rotating and static sources. These arise from the different motion patterns of these two types sources, they are typically not situated on same plane. To address this issue, a method based Modal Composition Beamforming (MCB) equivalent is proposed for separating which fully utilizes prior knowledge spatiotemporal properties The approach involves establishing Rotating-Static Sources Power...

Novel acoustic liner designs often incorporate new materials with non-uniform impedance distributions. Therefore, methods are required for their modelling and analysis. In this paper, a theoretical model is developed to investigate the scattering of sound waves from an axially symmetrical flow duct semi-infinite, azimuthally lining on wall. More specifically, incorporation Fourier series expansions into Wiener–Hopf method leads analytical matrix kernel, which further factorised by using...