In this work, we experimentally investigate turbulence ingesting rotor noise under various thrusting states. The broadband caused by ingestion is found to dominate at the normalized frequency range of $f\phantom{\rule{0}{0ex}}R/{U}_{\mathrm{\ensuremath{\infty}}}$ = 20 80 when low-thrusting conditions. Results also suggest that can be scaled Mach number scaling ${M}_{\mathrm{\ensuremath{\infty}}}^{2}$${M}_{c}^{4}$, where ${M}_{\mathrm{\ensuremath{\infty}}}$ freestream number, and ${M}_{c}$...

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 work, we conduct a numerical investigation of aerodynamics and aeroacoustics propeller blades with vibrations, which could occur in practical unmanned aerial vehicles as the are often made lightweight materials. The simulations resolve sound generation from unsteady turbulent flows using an acoustic-wave preserved artificial compressibility method. Then, projection to far-field observers is integral solution Ffowcs-Williams Hawkings equation. study shows that periodic blade...

The vehicle routing problem is common for drone delivery in urban areas, and the strategies can impact both transport efficiency community noise. In this article, we propose an optimization method to reduce en route noise during process. A hybrid cost function adopted evaluate quality of strategies, considering path length. evaluated based on efficient flight simulation assessment platform, which enables accurate sound source modeling a practical propagation computation realistic...

We investigate the aerodynamic and aeroacoustic characteristics of a small-scale drone rotor operating in axial descending flight. The integrated forces far-field noise are measured by wind tunnel experiments. Then, near-field flow structures corresponding source analysis presented based on computational aeroacoustics (CAA) simulations. found unique acoustic feature flight is haystacking-like spectral humps, possibly caused interaction between blade leading edge wake.

Unmanned aircraft systems (UAS) have promising potential for on-demand air transportation modes. Integration of UAS into existing airspace operations faces challenges, one these is the increased noise level caused by multiple vehicles operating within a limited airspace. Finding solutions to mitigate environmental crucial public acceptance and sustainable implementation in urban areas. In this paper, we introduce decentralized method guide flights, aiming minimize impact near intersection...

Turbulent flow in the blade boundary layer causes unsteady surface pressure and produces rotor noise broadband frequencies. intermittency affects creates sporadic high-strength sources. In this study, we demonstrate experimentally that strength of transient follows a log-normal distribution. A wavelet-based beamforming method is used to capture sources from 2 kHz 10 on with rotating speeds ranging 1800 rpm 7200 rpm. We suggest at different frequencies are generated by same generation...

Computational analysis with RANS method was carried out for the flow inside intake system of an industrial gas turbine. The influence different turbulence models on numerical predictions investigated in this study. results indicate that simulation obtains counter-rotating vortices similar to experimental result. However, variations swirl velocity magnitude and vortex structure were observed among models. Based total pressure data obtained using 2D-PIV probe measurement systems, statistical...

With the problem of urban traffic congestion becoming more worse, we are paying attention on Park and Ride(P&R), which is one aspect Transport Demand Management(TDM).As study layout P&R an important part planning, it plays a major role in strengthening TDM.On basis network system, this paper designs optimization model, taking total cost construction person's travel as minimum optimized goal.In end, also case about with solving model by Lingo mathematics software so to check effectiveness model.

A unique challenge of the urban air mobility noise assessment is configuration-dependent acoustic signature different designs, which installed sources must be considered. This work presents a computational aeroacoustics study four-rotor vehicle, focusing on near-field propagation considering installation effects vehicle components. The aerodynamic are computed using delayed detached eddy simulations, in interactional aerodynamics rotating propulsion and airframe addressed. calculated by...

The rapidly emerging market of urban air mobility has raised considerable public concern about noise exposure and annoyance, which is likely to limit the development future aerial transportation. This study presents a comprehensive approach evaluate flight an vehicle under various operating conditions provide practical strategies for low-noise path planning. Two methods with different fidelity levels are considered compared in evaluating sound sources. first based on efficient semi-empirical...

This work presents an improved artificial compressibility method that enables correct sound propagation behaviour in low Mach number flows. As extension of incompressible approaches, it offers the advantage computational costs since compressible flow equations are simplified under isentropic assumption, and coupling is preserved. The non-uniform speed considered this method, eigenvalue analysis modified governing reveals pseudo waves restores to physical acoustic waves. effect on dissipation...