Novel Propulsion System for VTOL Aircraft Based on Cycloidal Rotors Coupled With Wings

2020 ◽  
Author(s):  
F. F. Rodrigues ◽  
M. Habibnia ◽  
J. Pascoa
Keyword(s):  
Propulsion System ◽  
Experimental Results ◽  
Plasma Actuators ◽  
Environmental Disasters ◽  
Vertical Displacements ◽  
Novel Concept ◽  
Vtol Aircraft ◽  
Noise Production ◽  
Lower Noise

Abstract Aircraft being capable of Vertical Take-off and Landing (VTOL) and hover are increasingly emerging in various critical and routine applications. Rescue missions in roads and environmental disasters, observance and monitoring-based carriers, surveillance and payload carriage in environments that require high maneuverability and controllability are just a few examples in which this type of aircraft is essential. Helicopters are the most typical aircraft in this kind, but concerning the thrusting mechanism, several alternatives are yet in hand. The tendency to equip aircraft with cycloidal rotors (shortly say, cyclorotors) as means of Vertical Take-Off and Landing thrusters has increased in recent years. These devices present several advantages such as considerably lower noise production and more stable hover and vertical displacements in comparison with conventional screw propellers as used in helicopters. In the present work a novel concept of propulsion system combining two cycloidal rotors with a pair-wing system is presented. A double wing assembly is designed to place in between the two cyclorotors on each side of the aircraft. The bottom wing is intended to divide the flow in two separate portions through the downwash region of the front cycloidal rotor. To improve the efficiency of this propulsion system, the implementation of plasma actuators in the pair-wing system will be experimentally studied. The concept behind this novel propulsion system is explained and numerical and experimental results, that support its operation concept, are presented.

scholarly journals A Novel Concept Acquisition Approach Based on Formal Contexts

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Ting Qian ◽  
Ling Wei
Keyword(s):  
Data Analysis ◽  
Formal Concept Analysis ◽  
Real Life ◽  
Experimental Results ◽  
New Method ◽  
Concept Acquisition ◽  
Formal Concept ◽  
Knowledge Processing ◽  
Formal Concepts ◽  
Novel Concept

As an important tool for data analysis and knowledge processing, formal concept analysis (FCA) has been applied to many fields. In this paper, we introduce a new method to find all formal concepts based on formal contexts. The amount of intents calculation is reduced by the method. And the corresponding algorithm of our approach is proposed. The main theorems and the corresponding algorithm are examined by examples, respectively. At last, several real-life databases are analyzed to demonstrate the application of the proposed approach. Experimental results show that the proposed approach is simple and effective.

A Biomimetic Jellyfish-Inspired Jet Propulsion System Using an Iris Mechanism

2012 ◽  
Author(s):  
Kenneth Marut ◽  
Colin Stewart ◽  
Alex Villanueva ◽  
Dragan Avirovik ◽  
Shashank Priya
Keyword(s):  
Power Consumption ◽  
Test Stand ◽  
Propulsion System ◽  
Experimental Results ◽  
Jet Propulsion ◽  
Iris Diaphragm ◽  
Propulsion Mechanism ◽  
Vehicle Efficiency ◽  
Maximum Thrust

A bio-inspired jet propulsion mechanism was designed and developed for development of proficient unmanned undersea vehicles (UUVs). The propulsion mechanism mimics that of the Sarsia sp. jellyfish which measures approximately 1 cm in diameter. In order to achieve a biomimetic uniform bell contraction, an electrical motor was used in conjunction with a novel circumferential actuator based upon a mechanical iris diaphragm. This mechanism allows actuation of a deformable cavity. The current prototype was scaled to a diameter 10 times larger than Sarsia measuring 10 cm in diameter. The performance of the propulsion mechanism was analyzed both experimentally theoretically. The prototype was mounted on a test stand which allowed for measurement of thrust and power consumption. Analytical and experimental results were compared to that of the performance of Sarsia. It was found that the overall mechanism created a maximum thrust of 5.1 N with a calculated vehicle efficiency of 0.17% and proficiency of 4.8 s−1.

Strength Against Fracture of End Hemispherical Cavity Roller Under Static Loading: Experimental and Simulation Investigation

2020 ◽  
Vol 143 (7) ◽  
Author(s):  
Paresh C. Chhotani ◽  
Dipak P. Vakharia
Keyword(s):  
Fatigue Life ◽  
Maximum Shear Stress ◽  
Contact Stresses ◽  
Fracture Load ◽  
Experimental Results ◽  
Rolling Element Bearing ◽  
Catastrophic Failure ◽  
Rolling Element ◽  
Fracture Tests ◽  
Novel Concept

Abstract Enhancement in fatigue life of the rolling-element bearing has been captivating since years. The hollow concept had been triggered years back; however, it could not catch widespread applications due to catastrophic failure. Thus, any novel concept of the rolling element must be assessed for its strength against catastrophic failure before competing for better fatigue life on field with other alternatives. This paper commences with the outcomes of the comparative assessment of the experimental evaluation of strength against fracture under static loads for layered and hollow rollers with solid rollers, which devise the requirements for new concepts. The end hemispherical cavity (EHC) roller concept, being a proper geometrical blending of solidity and hollowness, prospects to overcome the strength concern along with a considerable reduction in contact stresses. Thus, experimental investigation was conducted with full-bearing fracture tests and individual roller specimens fracture tests for five variants: EHC, solid, layered, 61H, and 37H (hollow rollers with 61% and 37% hollowness, respectively). The simulations were carried out to support the outcomes of experimental trials. The experimental results with full-bearing samples and individual roller specimens demonstrated ranking as follows: EHC, 37H, layered, and 61H. The EHC roller concept was substantiated to be stronger than hollow and layered rollers besides prompting appreciable reduction in contact stresses compared with the solid roller. The simulation results agreed well with experimental results of fracture tests, and the recommendations from findings of failure theories (maximum normal stress, distortion energy, and maximum shear stress) adopted for estimating fracture load for rollers have been discussed.

Design of a Multijet Omnidirectional Propulsion System for Small Jet-Boats

2010 ◽  
Vol 132 (11) ◽  
Author(s):  
David Foley ◽  
Jean-Sebastien Plante
Keyword(s):  
High Speed ◽  
Flow Model ◽  
Open Loop ◽  
Propulsion System ◽  
Experimental Results ◽  
Control Algorithms ◽  
Control Laws ◽  
Low Speed ◽  
Advanced Control ◽  
Design Requirements

Jet-boats perform remarkably well at high-speed but lack low speed maneuverability for tight maneuvers such as docking. This paper presents a joystick controlled omnidirectional propulsion system for jet-boats. The concept uses a set of fixed jet nozzles disposed around the hull. When a force is commanded by the joystick, valves on each nozzle modulate the flow so that the sum of nozzle thrusts correspond to the commanded force. The positions and angles of the nozzles are optimized with an index of omnidirectionality quality based on the projection of a set of force solutions on a shell with the shape of a desired force space. The choice of valve positions and engine speeds is done by the numerical inversion of an internal viscous flow model. A 3D simulator, backed by experimental results, serves to (1) evaluate the ability of the proposed concept in meeting its design requirements and (2) develop control algorithms. Experimental results show that the proposed omnidirectional system is effective for low speed maneuverability with open-loop force control. The present work also offers an effective omnidirectional propulsion system that is easy to enhance with advanced control laws. Velocity feedback control is given as an example and shows important improvement of maneuverability and robustness to miscalibration.

Experimental Results in DBD Plasma Actuators for Airflow Control

2010 ◽  
Author(s):  
Carlo Borghi ◽  
Andrea Cristofolini ◽  
Chiara Latini ◽  
Gabriele Neretti ◽  
Alessandro Gurioli ◽  
...  
Keyword(s):  
Experimental Results ◽  
Plasma Actuators ◽  
Dbd Plasma
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