scholarly journals A Comparison of Isolated and Ducted Fixed-Pitch Propellers under Non-Axial Inflow Conditions

Aerospace ◽  
2020 ◽  
Vol 7 (8) ◽  
pp. 112
Author(s):  
Michael Cerny ◽  
Christian Breitsamter
Keyword(s):  
Flow Field ◽  
Unmanned Aerial Vehicles ◽  
Systematic Investigation ◽  
Major Influence ◽  
Small Scale ◽  
Highly Efficient ◽  
Strong Interest ◽  
Aerial Vehicles ◽  
Inflow Conditions ◽  
Fixed Pitch

A strong interest in highly-efficient, small-scale propeller configurations can be recognized, especially due to the currently growing number of and usage possibilities for unmanned aerial vehicles (UAVs). Although a variety of different propulsion concepts already exist on the market or are discussed in the literature, there is still a demand for a systematic investigation to compare such configurations, in particular, small-scale propellers with a fixed pitch, which are analyzed in this work. Therefore, different configurations of small-scale propellers with a fixed pitch are analyzed in this paper. They were operated as isolated single propellers and as ducted propellers in a cylindrical wing. Furthermore, due to their flight envelope, UAVs are likely to operate at highly inclined inflow conditions and even under reverse inflow. These non-axial inflow conditions have a major influence on the flow field around a propeller. In order to investigate this influence, all analyses were performed at a range of inflow angles in relation to the propeller axis from αdisc=0° to 180°.

scholarly journals Unmanned Aerial Vehicles for Wildland Fires: Sensing, Perception, Cooperation and Assistance

Drones ◽  
2021 ◽  
Vol 5 (1) ◽  
pp. 15
Author(s):  
Moulay A. Akhloufi ◽  
Andy Couturier ◽  
Nicolás A. Castro
Keyword(s):  
Unmanned Aerial Vehicles ◽  
Wildland Fire ◽  
Fire Intensity ◽  
Economic Losses ◽  
Small Scale ◽  
Environmental Damage ◽  
Unmanned Aerial Systems ◽  
Wildland Fires ◽  
Natural Risk ◽  
Aerial Vehicles

Wildfires represent a significant natural risk causing economic losses, human death and environmental damage. In recent years, the world has seen an increase in fire intensity and frequency. Research has been conducted towards the development of dedicated solutions for wildland fire assistance and fighting. Systems were proposed for the remote detection and tracking of fires. These systems have shown improvements in the area of efficient data collection and fire characterization within small-scale environments. However, wildland fires cover large areas making some of the proposed ground-based systems unsuitable for optimal coverage. To tackle this limitation, unmanned aerial vehicles (UAV) and unmanned aerial systems (UAS) were proposed. UAVs have proven to be useful due to their maneuverability, allowing for the implementation of remote sensing, allocation strategies and task planning. They can provide a low-cost alternative for the prevention, detection and real-time support of firefighting. In this paper, previous works related to the use of UAV in wildland fires are reviewed. Onboard sensor instruments, fire perception algorithms and coordination strategies are considered. In addition, some of the recent frameworks proposing the use of both aerial vehicles and unmanned ground vehicles (UGV) for a more efficient wildland firefighting strategy at a larger scale are presented.

Optimizing Perimeter Surveillance Drones to enhance the security system of unmanned aerial vehicles

2021 ◽  
Vol 2 (2) ◽  
pp. 105-115
Author(s):  
Mahmod Al-Bkree
Keyword(s):  
Unmanned Aerial Vehicles ◽  
Security System ◽  
Small Scale ◽  
Security Systems ◽  
Ongoing Research ◽  
Aerial Vehicles ◽  
Aerial Vehicle ◽  
Initial Results

This work is to optimize perimeter surveillance and explore the distribution of ground bases for unmanned aerial vehicles along the Jordanian border and optimize the set of technologies for each aerial vehicle. This model is part of ongoing research on perimeter security systems based on unmanned aerial vehicles. The suggested models give an initial insight about selecting technologies carried by unmanned aerial vehicles based on their priority; it runs for a small scale system that can be expanded, the initial results show the need for at least four ground bases along the length of the border, and a selected set of various technologies for each vehicle.

scholarly journals Unmanned aerial vehicles reveal the impact of a total solar eclipse on the atmospheric surface layer

2019 ◽  
Vol 475 (2229) ◽  
pp. 20190212 ◽  
Author(s):  
Sean C. C. Bailey ◽  
Caleb A. Canter ◽  
Michael P. Sama ◽  
Adam L. Houston ◽  
Suzanne Weaver Smith
Keyword(s):  
Surface Layer ◽  
Unmanned Aerial Vehicles ◽  
Solar Eclipse ◽  
Atmospheric Surface Layer ◽  
Small Scale ◽  
Stable Layer ◽  
Holistic View ◽  
Near Surface ◽  
Aerial Vehicles ◽  
The Impact

We use unmanned aerial vehicles to interrogate the surface layer processes during a solar eclipse and gain a comprehensive look at the changes made to the atmospheric surface layer as a result of the rapid change of insolation. Measurements of the atmospheric surface layer structure made by the unmanned systems are connected to surface measurements to provide a holistic view of the impact of the eclipse on the near-surface behaviour, large-scale turbulent structures and small-scale turbulent dynamics. Different regimes of atmospheric surface layer behaviour were identified, with the most significant impact including the formation of a stable layer just after totality and evidence of Kelvin–Helmholtz waves appearing at the interface between this layer and the residual layer forming above it. The decrease in surface heating caused a commensurate decrease in buoyant turbulent production, which resulted in a rapid decay of the turbulence in the atmospheric surface layer both within the stable layer and in the mixed layer forming above it. Significant changes in the wind direction were imposed by the decrease in insolation, with evidence supporting the formation of a nocturnal jet, as well as backing of the wind vector within the stable layer.

Numerical Study of Effects of AJVG on Aerodynamic Performance and Speed Control of Small-Scale Fixed-Pitch HAWT

2014 ◽  
Author(s):  
Xiang Gao ◽  
Jun Hu ◽  
Zhiqiang Wang ◽  
Chenkai Zhang
Keyword(s):  
Flow Field ◽  
Wind Turbine ◽  
Output Power ◽  
Vortex Generator ◽  
Speed Control ◽  
Aerodynamic Performance ◽  
Small Scale ◽  
Air Jet ◽  
Blade Tip ◽  
Fixed Pitch

Due to the feature of structure simplicity, lower production cost and maintenance ease, fixed pitch variable speed wind turbine has been widely used in non-grid-connected wind power systems. The calculation of wind turbine performance plays an important part in the design of wind turbines. Aerodynamic performance calculation is particularly significant in the fixed pitch stall-regulated wind turbine aerodynamic design process. To enhance the output power and power coefficient of wind turbine, active flow control technologies such as vortex generator are adopted in recent years. In this paper, a small wind turbine with air jet vortex generator (AJVG) on the blade tip is designed, and the output power of the wind turbine gets changed by operating the air jet. Computational Fluid Dynamics method is chosen to obtain aerodynamic characteristics of the wind turbine with/without AJVG and these features are furtherly integrated with speed control method to get speed control strategy under full-speed circumstance. It can be found after complete comparison that through setting AJVG at the blade tip, the new speed control features can help make it operate more stably in a wide range of wind speed without changing the existing wind turbine blades profiles and pitch angle. Also details of the flow field are obtained when solving the three-dimensional Navier-Stokes Equations. By analyzing the flow field of wind turbine with/without AJVG, the influence mechanism of the AJVG is demonstrated in this paper.

scholarly journals SYSTEMS OF RADIO-ELECTRONIC FIGHT AGAINST PILOTLESS VEHICLES MULTIROTOR TYPE IN DISTRICTS OF CONDUCT BATTLE ACTIONS

2020 ◽  
pp. 44-53
Author(s):  
R. M. Oliinyk ◽  
S. V. Tsilyna ◽  
Y. M. Zhyvets ◽  
O. V. Yermolenko
Keyword(s):  
Comparative Analysis ◽  
Unmanned Aerial Vehicles ◽  
Armed Forces ◽  
Small Scale ◽  
Information Component ◽  
Air Defense ◽  
Aerial Vehicles ◽  
The World ◽  
Modern Warfare ◽  
Methods Of Control

In modern warfare, the information component is crucial for both sides of the conflict. Donetsk and Luhansk regions have become a kind of bridgehead for testing and application in the operation of unmanned aerial vehicles of various dimensions and functional purposes, the most common of which are small reconnaissance unmanned aerial vehicles. Dozens of enemy vehicles are gathering information about the location of the Ukrainian military. To date, no state is ready to withstand planned attacks by unmanned aerial vehicles. Traditional air defense weapons are designed for large and long-range targets, while the modern line of drones consists of nano-, micro- and mini-devices flying at low altitudes. A comparative analysis of modern means of counteracting unmanned aerial vehicles and conclusions about the possibility of their use in the Armed Forces of Ukraine. The newest means of destruction of unmanned aerial vehicles of the leading countries of the world are considered. The issue of the possibility of blocking the work of enemy drones is covered in zones (areas) of hostilities. Ways to increase the effectiveness of small - scale unmanned aerial vehicles are proposed. Priorities in the implementation of programs for the development of modern domestic means of destruction of unmanned aerial vehicles can be considered the use of means of interception or destruction by electronic countermeasures. The relevance of the study lies in the analysis of the main available methods of control with unmanned aerial vehicles, development of perspective approaches and acquaintance with modern achievements and directions of development of means of struggle against drones applied by the enemy.

scholarly journals Aerodynamic Performance of an Octorotor SUAV with Different Rotor Spacing in Hover

Processes ◽  
2020 ◽  
Vol 8 (11) ◽  
pp. 1364
Author(s):  
Yao Lei ◽  
Yuhui Huang ◽  
Hengda Wang
Keyword(s):  
Flow Field ◽  
Unmanned Aerial Vehicles ◽  
Aerodynamic Performance ◽  
Aerodynamic Efficiency ◽  
Experimental Platform ◽  
Vorticity Distribution ◽  
Aerial Vehicles ◽  
Spacing Ratio ◽  
Computational Fluid Dynamics Cfd ◽  
Cfd Method

To study the aerodynamic performance of hovering octorotor small unmanned aerial vehicles (SUAV) with different rotor spacing, the computational fluid dynamics (CFD) method is applied to analyze the flow field of an octorotor SUAV in detail. In addition, an experimental platform is built to measure the thrust and power of the rotors with rotor spacing ratios L/D of 1.0, 1.2, 1.4, 1.6, and 1.8, sequentially. According to the theory of momentum, rotor aerodynamic performance is obtained with qualitative analysis. Further analysis with numerical simulation is presented with the flow field of the octorotor SUAV, the vorticity distribution, velocity distribution, pressure distribution, and streamline. The results show that the aerodynamic performance varies with the rotor spacing. Specifically, the aerodynamic performance is poor at L/D = 1.0, which is accompanied with strong interaction of wake and tip vortexes and interaction with each other. However, the aerodynamic efficiency is much improved with a larger rotor spacing, especially achieving the highest at L/D = 1.8, which is considered to be the best rotor spacing ratio for this kind of octorotor SUAV.

scholarly journals A Survey of Small-Scale Unmanned Aerial Vehicles: Recent Advances and Future Development Trends

2014 ◽  
Vol 02 (02) ◽  
pp. 175-199 ◽  
Author(s):  
Guowei Cai ◽  
Jorge Dias ◽  
Lakmal Seneviratne
Keyword(s):  
Unmanned Aerial Vehicles ◽  
Future Development ◽  
Flight Control ◽  
Ground Control ◽  
Small Scale ◽  
Dynamics Modeling ◽  
Aerial Vehicles ◽  
Recent Advances ◽  
Ground Control Station ◽  
Military Applications

This paper provides a brief overview on the recent advances of small-scale unmanned aerial vehicles (UAVs) from the perspective of platforms, key elements, and scientific research. The survey starts with an introduction of the recent advances of small-scale UAV platforms, based on the information summarized from 132 models available worldwide. Next, the evolvement of the key elements, including onboard processing units, navigation sensors, mission-oriented sensors, communication modules, and ground control station, is presented and analyzed. Third, achievements of small-scale UAV research, particularly on platform design and construction, dynamics modeling, and flight control, are introduced. Finally, the future of small-scale UAVs' research, civil applications, and military applications are forecasted.

scholarly journals Challenges and perspective with using a group of small combat unmanned aerial vehicles

2021 ◽  
Vol 13 (S) ◽  
pp. 245-255
Author(s):  
Mamuka Ya. ZOIDZE ◽  
Givi O. SANADZE ◽  
Oleksandr V. KRAKHMALYOV ◽  
Olena I. ZINCHENKO ◽  
Vitalii O. BRUSENTSEV
Keyword(s):  
Unmanned Aerial Vehicles ◽  
New Technologies ◽  
High Capacity ◽  
High Energy ◽  
Small Scale ◽  
Development Trends ◽  
Nano Technology ◽  
Aerial Vehicles ◽  
Aerial Vehicle ◽  
Intelligent Methods

The article discusses the features of small unmanned aerial vehicles, perspectives, directions for the development of unmanned aerial vehicles with integrated combat units. The development trends of unmanned aerial vehicles indicate the direction of the use of the unmanned aerial vehicle in the group of small unmanned aerial vehicles operating on the principle of autonomous management. The main problems are related to solving management and groupwork tasks in the group, which leads to the use of group intelligence methods. The possibilities of group use of unmanned aerial vehicles are analyzed. One of the main goals of small drone technology is to create energy sources with high energy capacity and power. The exchange of information within a group of unmanned aerial vehicles requires the use of group-based intelligent methods based on self-organized decentralized management. Such methods are based on the self-organization of movement and communication in a group of insects, fish or birds. The analysis shows that the development trends of small-scale drones are primarily driven by advances in micro and nano technology, new approaches to aerodynamics and management, the creation of high-capacity power supplies and engines, creating autonomous micro and nano systems for navigation and communication using agreed integrated concepts. The direction of new technologies for use in the group of small unmanned aerial vehicles based on the principle of autonomous control is revealed. An algorithm for organizing interaction in a group of unmanned aerial vehicles is presented and the relevant tasks are discussed.

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