Simulation of Emerging Urban Air Mobility Noise Propagation Using Acoustic Raytracing Techniques In Complicated 3D Urban Environments

One of the primary challenges facing Urban Air Mobility (UAM) and the safe integration of Unmanned Aircraft Systems (UAS) in the urban airspace is the availability of robust, reliable navigation and Sense-and-Avoid (SAA) systems. Global Navigation Satellite Systems (GNSS) are typically the primary source of positioning for most air and ground vehicles and for a growing number of UAS applications; however, their performance is frequently inadequate in such challenging environments. This paper performs a comprehensive analysis of GNSS performance for UAS operations with a focus on failure modes in urban environments. Based on the analysis, a guidance strategy is developed which accounts for the influence of urban structures on GNSS performance. A simulation case study representative of UAS operations in urban environments is conducted to assess the validity of the proposed approach. Results show improved accuracy (approximately 25%) and availability when compared against a conventional minimum-distance guidance strategy.

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Wall-Resolved LES Modeling of a Wind Turbine Airfoil at Different Angles of Attack

Journal of Marine Science and Engineering ◽

10.3390/jmse8030212 ◽

2020 ◽

Vol 8 (3) ◽

pp. 212 ◽

Cited By ~ 2

Author(s):

Irene Solís-Gallego ◽

Katia María Argüelles Díaz ◽

Jesús Manuel Fernández Oro ◽

Sandra Velarde-Suárez

Keyword(s):

Boundary Layer ◽

Wind Turbine ◽

Acoustic Waves ◽

Urban Environments ◽

Far Field ◽

Noise Generation ◽

Noise Propagation ◽

Trailing Edge ◽

Wind Turbine Airfoil ◽

Les Model

Noise has arisen as one of the main restrictions for the deployment of wind turbines in urban environments or in sensitive ecosystems like oceans for offshore and coastal applications. An LES model, adequately planned and resolved, is useful to describe the noise generation mechanisms in wind turbine airfoils. In this work, a wall-resolved LES model of the turbulent flow around a typical wind turbine airfoil is presented and described in detail. The numerical results obtained have been validated with hot wire measurements in a wind tunnel. The description of the boundary layer over the airfoil provides an insight into the main noise generation mechanism, which is known to be the scattering of the vortical disturbances in the boundary layer into acoustic waves at the airfoil trailing edge. In the present case, 2D wave instabilities are observed in both suction and pressure sides, but these perturbations are diffused into a turbulent boundary layer prior to the airfoil trailing edge, so tonal noise components are not expected in the far-field noise propagation. The results obtained can be used as input data for the prediction of noise propagation to the far-field using a hybrid aeroacoustic model.

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The influence of natural and urban environments on attentional processing of emotional stimuli

PsycEXTRA Dataset ◽

10.1037/e522252014-234 ◽

2014 ◽

Author(s):

Chrono Nu ◽

Katie Mullin ◽

Hailey Edwards ◽

Kailey Kornhauser ◽

Russell Costa ◽

...

Keyword(s):

Urban Environments ◽

Emotional Stimuli ◽

Attentional Processing

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Minimetrò in Perugia as leverage for urban regeneration

TERRITORIO ◽

10.3280/tr2019-091015 ◽

2020 ◽

pp. 148-163

Author(s):

Luca Fondacci

Keyword(s):

Urban Regeneration ◽

Urban Environments ◽

Low Carbon ◽

Sustainable Mobility ◽

Field Surveys ◽

Peripheral Area ◽

Alternative Means ◽

Considerable Impact ◽

The City ◽

Historical Centre

In the 1970s, the fragile historical centre of the city of Perugia was a key area where the binomial of sustainable mobility and urban regeneration was developed and applied. At the turn of the xxi century, the low carbon automatic people-mover Minimetrò broadened that application from the city's historical centre to the outskirts, promoting the enhancement of several urban environments. This paper is the outcome of an investigation of original sources, field surveys and direct interviews, which addresses the Minimetrò as the backbone of a wide regeneration process which has had a considerable impact on the economic development of a peripheral area of the city which was previously devoid of any clear urban sense. The conclusion proposes some solutions to improve the nature of the Minimetrò as an experimental alternative means of transport.

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