scholarly journals Determining the Aerodynamic Characteristics of a Propeller-Driven Anti-UAV Fighter While Designing Air Propellers

2021 ◽  
Vol 2021 (4) ◽  
pp. 53-67
Author(s):  
Vasyl Loginov ◽  
Yevgen Ukrainets ◽  
Viktor Popov ◽  
Yevgen Spirkin
Keyword(s):  
Wind Tunnel ◽  
Numerical Methods ◽  
High Efficiency ◽  
Aerodynamic Characteristics ◽  
The Body ◽  
Physical Experiments ◽  
Thrust And Torque ◽  
Aircraft Configurations ◽  
Aerodynamic Configuration ◽  
Selection Of

Abstract Given the rising importance of unmanned aerial vehicles (UAVs), this article addresses the urgent scientific problem of determining the aerodynamic characteristics of a UAV while laying out the propellers for the wings. We discuss the methodology for experimental wind-tunnel studies of aircraft configurations with propellers. It is shown that a characteristic feature of the configuration small-elongation wing with propellers is the absence of elements that are not affected by propellers. This feature makes it difficult to implement and automate a wind tunnel experiment, since there are problems with providing similar criteria for a working propeller; it is difficult to achieve perfect balancing for solid drive propellers, which causes vibration, the level of which depends on uncontrolled factors; the inability to neglect the presence of the body elements influence to the blades of propellers; the difficulty of direct measuring propeller thrust and torque. The presented methodology involves the integrated usage of experimental and numerical methods to eliminate the difficulties in conducting physical experiments in a wind tunnel. This approach makes it possible to combine the high credibility of experimental data in the study of the physical essence of phenomena with high efficiency and accuracy in determining aerodynamic characteristics by numerical methods. Using this approach, we established dependences of the aerodynamic characteristics of the small-elongation wing configuration with counter-rotating propellers on the geometric and kinematic parameters of the configuration for other extensions and constrictions of the wings. These data can serve as the basis for the development of recommendations for the selection of sensible geometric parameters of the aerodynamic configuration of a small-elongation wing with counter-rotating propellers.

scholarly journals Pipeline Compressor Redesign With the Consideration of Both Noise and Performance

2000 ◽  
Author(s):  
Yuri I. Biba ◽  
Zheji Liu ◽  
D. Lee Hill
Keyword(s):  
High Efficiency ◽  
Aerodynamic Characteristics ◽  
The Body ◽  
Design Parameters ◽  
Original Design ◽  
Tonal Noise ◽  
Experimental Performance ◽  
Expected Performance ◽  
Computational Fluid Dynamics Cfd ◽  
And Performance

A complete effort to redesign the aerodynamic characteristics of a single-stage pipeline compressor is presented. The components addressed are the impeller, diffuser region, and the volute. The innovation of this effort stems from the simultaneous inclusion of both the noise and aerodynamic performance as primary design parameters. The final detailed flange-to-flange analysis of the new components clearly shows that the operating range is extended and the tonal noise driven by the impeller is reduced. This is accomplished without sacrificing the existing high efficiency of the baseline machine. The body of the design effort uses both Computational Fluid Dynamics (CFD) and vibro-acoustics technology. The predictions are anchored by using the flange-to-flange analysis of the original design and its experimental performance data. By calculating delta corrections and assuming that these deltas are approximately the same for the new design, the expected performance is extrapolated.

Research and selection of MALE wing profile

2019 ◽  
Vol 91 (2) ◽  
pp. 264-271 ◽  
Author(s):  
Cezary Gorniak ◽  
Zdobyslaw Jan Goraj ◽  
Bartosz Olszanski
Keyword(s):  
Wind Tunnel ◽  
Early Stage ◽  
Phase 1 ◽  
Lift Coefficient ◽  
High Volume ◽  
Aerodynamic Characteristics ◽  
Preliminary Design ◽  
Content Type ◽  
Wing Section ◽  
Selection Of

Purpose The purpose of this research is a preliminary selection of wing section, which would be the best suited for PW-100 – a MALE class UAV of 600 kg weight. PW-100 will be used as a testing platform in different institutions such as research institutes, industry research centers or universities of technology (phase 1) to enable the in-flight testing of various on-board systems (mobile radars, thermovision sensors, chemical sensors, antennas, teledetection systems and others). Untypical layout of PW-100 resulted from the plans of further development of this configuration for a military application. Design/methodology/approach Important role in the research described in this paper plays the selection of main wing section to fulfil the preliminary requirements regarding maximum lift coefficient, minimum drag, aerodynamic efficiency etc. Two different wing sections (R1082 and SA19) were tested in wind tunnel, both with flaps deflected at the range of 0°-30°. Experimental measurements were performed in the low turbulence wind tunnel with closed test section of 45 cm × 35 cm. Numerical simulations of the flow around the wing sections were performed using MSES code. Boundary conditions were assumed basing on the typical mission of PW-100 for flight altitude around 9,000 m, speed of 110 km/h what results in Re = 956,000. Findings Lift coefficients obtained from both experimental and numerical methods for single slatted airfoil SA19 are much higher than that of get for Ronch R1082 airfoil. PW-100 aircraft with SA19 airfoils will be able to be trimmed and fly at any altitude up to 9,000 m and with an arbitrary weight up to 600 kg. Aerodynamic characteristics of SA19 remain smoother and more predictable than that of R1082 airfoil. The very promising properties of SA19 airfoil are well known to the authors since the beginning of last decade when PW team worked together with IAI team on CAPECON project and now it was fully confirmed by this research. Practical implications It was confirmed that selection of the proper wing section for the special mission performed by UAV is of the highest importance decision to be taken at the preliminary design phase. Because there is a limited access to the base of technical parameters in many different UAVs classes and the classical analysis of trends cannot be fully applied, the wing section analysis, either experimental or numerical, must be performed. The situation is much worse than in the case of manned aircrafts because most of the modern UAVs are made of carbon or glass fiber, and therefore, there is no chance for analysis of trends. Originality/value This paper presents a very efficient method of assessing the influence of wing section on aircraft performance adopted for MALE class UAV, especially in an early stage of preliminary design process. The assessment is built mainly on three requirements: Maximum 2D lift coefficient for take-off configuration with flap deflected on 20 degrees should be greater than 2.4. Endurance factor CL1.5/CD for loitering conditions (Ma = 0.5 and CD0 = 0.008) should be greater than 110. The relative wing section thickness should be greater/equal than 19 per cent (it is required for high volume fuel tank located in the wings).

scholarly journals Wind Tunnel Tests on Aerodynamic Forces of Road Vehicles Under Unsteady Wind Conditions

2018 ◽  
Vol 15 (4) ◽  
pp. 6064-6077
Author(s):  
M. Sumida ◽  
S. Morita
Keyword(s):  
Wind Tunnel ◽  
Wind Tunnel Test ◽  
Aerodynamic Characteristics ◽  
The Body ◽  
Wind Condition ◽  
Road Vehicles ◽  
Fluid Forces ◽  
Lift Forces ◽  
Drag And Lift ◽  
Prism Model

This paper describes the results obtained from a wind tunnel test on the aerodynamic characteristics of road vehicles subjected to unsteady wind. In order to study the aerodynamic response of vehicles under atmospheric fluctuations, the velocity of the wind has been simulated in a pulsating state, where vehicles at a constant speed are driving in air with large wind oscillation. On the other hand, we consider three types of vehicles: two types of the Ahmed model, with slant angles of 0° and 30°, and the basic rectangular-prism model. The effect of wind oscillation on the drag and lift forces acting on the vehicle models under a pulsating wind condition has been extracted by comparing it to the forces under steady wind conditions. The oscillation of the wind exerts a significant effect on the fluid forces, and the drag and lift forces change with time in a peculiar way, depending on the body shape of the vehicle.

PENGEMBANGAN BAHAN AJAR IPA SMP PADA TEMA ENERGI DALAM TUBUH MENGGUNAKAN METODE 4STMD

EDUSAINS ◽  
2019 ◽  
Vol 8 (2) ◽  
pp. 166-175
Author(s):  
Gia Juniar Nur Wahidah ◽  
Sjaeful Anwar
Keyword(s):  
Concept Maps ◽  
The Body ◽  
Instructional Materials ◽  
Teaching Material ◽  
Test Results ◽  
Teaching Materials ◽  
Eligibility Criteria ◽  
Material Development ◽  
Selection Step ◽  
Selection Of

Abstract This research aims to produce science teaching materials in junior level with Energy in The Body as the theme using Four Steps Teaching Material Development  (4STMD). The material is presented in an integrated way so that students can  think holistically and contextually. The method used in this study is Research and Development. In this R&D methods is used 4STMD. There are four steps done on the development of teaching materials, the selection step, structuring step, characterization, and didactic reduction. Selection step includes the selection of indicators in accordance with the demands of the curriculum which is then developed with the selection of concepts and values that are integrated with the concept of science. Structuring step includes make macro structures, concept maps, and multiple representations. Characterization's step includes preparation instruments, then  trial to students to identify difficult concepts. The last, didactic reduction was done by neglect and the annotations in the form of sketches.The test results readability aspect instructional materials lead to the conclusion that by determining the main idea, the legibility of teaching materials reached 67%, with moderate readability criteria. Test results of feasibility aspects based on the results of questionnaires to the 11 teachers lead to the conclusion that the overall, level of eligibility teaching materials reached 91% with the eligibility criteria well. Keywords: teaching materials; energy; 4STMD Abstrak Penelitian ini bertujuan untuk menghasilkan bahan ajar IPA SMP pada tema Energi dalam Tubuh menggunakan metode Four Steps Teaching Material Development (4STMD). Materi disajikan secara terpadu sehingga memacu siswa untuk berpikir secara holistik dan kontekstual. Metode penelitian yang digunakan pada penelitian ini adalah metode penelitian dan pengembangan. Dalam penelitian dan pengembangan yang ini, digunakan metode Four Steps Teaching Material Development (4STMD). Terdapat empat tahap yang dilakukan pada pengembangan bahan ajar, yakni tahap seleksi, strukturisasi, karakterisasi, dan reduksi didaktik. Tahap seleksi meliputi pemilihan indikator yang sesuai dengan tuntutan kurikulum yang kemudian dikembangkan dengan pemilihan konsep dan nilai yang diintegrasikan dengan konsep IPA. Tahap strukturisasi meliputi pembuatan struktur makro, peta konsep, dan multipel representasi dari materi. Tahap karakterisasi meliputi penyusunan instrumen karakterisasi, kemudian uji coba kepada siswa untuk mengidentifikasi konsep sulit. Tahap terakhir, yaitu reduksi didaktik konsep terhadap konsep sulit. Reduksi didaktik yang dilakukan berupa pengabaian dan penggunaan penjelasan berupa sketsa. Hasil uji aspek keterbacaan bahan ajar menghasilkan kesimpulan bahwa berdasarkan penentuan ide pokok, keterbacaan bahan ajar mencapai 67%, dengan kriteria keterbacaan tinggi. Hasil uji aspek kelayakan berdasarkan hasil angket terhadap 11 orang guru menghasilkan kesimpulan bahwa secara keseluruhan tingkat kelayakan bahan ajar mencapai 91% dengan kriteria kelayakan baik sekali. Kata Kunci: bahan ajar; energi; 4STMD  Permalink/DOI: http://dx.doi.org/10.15408/es.v8i2.2039  

Inspector Quadro - the complex of preparation for the treatment of ectoand endoparasitoses in cats and dogs

2018 ◽  
Vol 12 (2) ◽  
pp. 75-84
Author(s):  
M.V. Arisov ◽  
I.P. Belykh ◽  
V.V. Artemov
Keyword(s):  
Body Weight ◽  
Clinical Picture ◽  
High Efficiency ◽  
The Body ◽  
Negative Effects ◽  
Laboratory Methods ◽  
Diagnosis Of Infection

The purpose of the research: the study of the efficacy of the preparations for veterinary use "Inspector Quadro C" and "Inspector Quadro K" against ecto- and endoparasitoses of dogs and cats. Materials and methods. Studies were conducted on spontaneously infected dogs and cats of different sexes, age, weight and breed. The diagnosis of infection with ectoparasites was made based on the clinical picture and laboratory methods of investigation (microscopy of scrapings taken from ectoparasitized skin areas, examination of the coat for fleas, lice, worms, ixodids). Infection with helminths was established by detecting eggs of helminths in faeces of animals by the method of Füleleborn and mature segments of cestodes. Preparations were applied to the animals by drip application on dry undamaged skin in places inaccessible to licking in a dose of 0.1-0.4 ml per 1 kg of body weight. The results were statistically processed. Results and discussion. "Inspector Quadro S" and "Inspector Quadro K" showed 100% efficacy at sarcoptosis in dogs, notoedrosis in cats, otodectosis in dogs and cats, ixodidoses and entomoses. "Inspector Quadro C" showed a high efficiency (92.3%) at demodecosis in dogs. However, single mites were found in one dog. 100% efficacy of "Inspector Quadro C" and "Inspector Quadro K" has been established against intestinal nematodes and cestodes in dogs and cats. Negative effects of drugs on the body of animals have not been revealed.

Tail shapes lead to different propulsive mechanisms in the body/caudal fin undulation of fish

2020 ◽  
pp. 095440622096768
Author(s):  
Jialei Song ◽  
Yong Zhong ◽  
Ruxu Du ◽  
Ling Yin ◽  
Yang Ding
Keyword(s):  
Numerical Simulation ◽  
Aspect Ratio ◽  
High Efficiency ◽  
The Body ◽  
Caudal Fin ◽  
Fish Model ◽  
Swimming Efficiency ◽  
Simulation Results ◽  
Propulsive Mechanism ◽  
High Depth

In this paper, we investigate the hydrodynamics of swimmers with three caudal fins: a round one corresponding to snakehead fish ( Channidae), an indented one corresponding to saithe ( Pollachius virens), and a lunate one corresponding to tuna ( Thunnus thynnus). A direct numerical simulation (DNS) approach with a self-propelled fish model was adopted. The simulation results show that the caudal fin transitions from a pushing/suction combined propulsive mechanism to a suction-dominated propulsive mechanism with increasing aspect ratio ( AR). Interestingly, different from a previous finding that suction-based propulsion leads to high efficiency in animal swimming, this study shows that the utilization of suction-based propulsion by a high- AR caudal fin reduces swimming efficiency. Therefore, the suction-based propulsive mechanism does not necessarily lead to high efficiency, while other factors might play a role. Further analysis shows that the large lateral momentum transferred to the flow due to the high depth of the high- AR caudal fin leads to the lowest efficiency despite the most significant suction.

Research on the methods and means of action strength training in aerobics training

2021 ◽  
pp. 002072092110042
Author(s):  
Xiaona Yang ◽  
Yang Ji ◽  
Da Ke ◽  
Fang Li
Keyword(s):  
Strength Training ◽  
Team Member ◽  
High Efficiency ◽  
Colleges And Universities ◽  
The Body ◽  
Energy Output ◽  
Control Group ◽  
Experimental Sample ◽  
Training Method ◽  
Core Strength

Aerobics is a beautiful and rhythmic sport. In recent years, aerobics has developed rapidly, and has become one of the essential courses of physical education in Colleges and universities. But the existing aerobics courses in Colleges and universities are less involved in the training process of action strength. Lack of strength quality is a common shortcoming of Aerobics Athletes in Colleges and universities. Therefore, this paper puts forward the methods and means of action strength training in aerobics training. According to the characteristics of competitive aerobics, combined with the traditional training strategy of action strength, this paper formulates the method of action strength training suitable for College Aerobics athletes. In order to further verify the effectiveness of this method, this paper takes a university aerobics team as an experimental sample to carry out a comparative analysis of the effect of action strength training. Relevant studies have proved that core strength training has the following effects on aerobics players: 1. Helps the calisthenics team member stabilize the trunk, improve the body's control ability and balance ability. 2. It is conducive to completing difficult movements of calisthenics with high efficiency and low energy consumption. 3. Helps the aerobics team member to enhance the special strength. 4. It can effectively prevent sports injuries. 5. It can improve the direction change and displacement speed of the body. 6. It can improve the energy output of the core strength to the limbs and other muscle groups during movement, so that the movement can be completed more perfectly.According to the results of the experiment, the explosive force and endurance of the experimental group after 8 weeks of training have been significantly improved, and formed a more obvious difference with the control group. The aerobics training method developed in this paper can be divided into two stages: the initial stage and the middle stage, which can better meet the students with different physical qualities. At the end of this paper, a fast strength training method is introduced, and the characteristics of different training methods are analyzed.

scholarly journals A High Efficiency Low Noise RF-to-DC Converter Employing Gm-Boosting Envelope Detector and Offset Canceled Latch Comparator

Electronics ◽  
2021 ◽  
Vol 10 (9) ◽  
pp. 1078
Author(s):  
Thi Thuy Pham ◽  
Dongmin Kim ◽  
Seo-Hyeong Jeong ◽  
Junghyup Lee ◽  
Donggu Im
Keyword(s):  
Power Consumption ◽  
High Efficiency ◽  
Supply Voltage ◽  
Current Source ◽  
Low Noise ◽  
The Body ◽  
Common Source ◽  
Conversion Gain ◽  
Input Transistor ◽  
Envelope Detector

This work presents a high efficiency RF-to-DC conversion circuit composed of an LC-CL balun-based Gm-boosting envelope detector, a low noise baseband amplifier, and an offset canceled latch comparator. It was designed to have high sensitivity with low power consumption for wake-up receiver (WuRx) applications. The proposed envelope detector is based on a fully integrated inductively degenerated common-source amplifier with a series gate inductor. The LC-CL balun circuit is merged with the core of the envelope detector by sharing the on-chip gate and source inductors. The proposed technique doubles the transconductance of the input transistor of the envelope detector without any extra power consumption because the gate and source voltage on the input transistor operates in a differential mode. This results in a higher RF-to-DC conversion gain. In order to improve the sensitivity of the wake-up radio, the DC offset of the latch comparator circuit is canceled by controlling the body bias voltage of a pair of differential input transistors through a binary-weighted current source cell. In addition, the hysteresis characteristic is implemented in order to avoid unstable operation by the large noise at the compared signal. The hysteresis window is programmable by changing the channel width of the latch transistor. The low noise baseband amplifier amplifies the output signal of the envelope detector and transfers it into the comparator circuit with low noise. For the 2.4 GHz WuRx, the proposed envelope detector with no external matching components shows the simulated conversion gain of about 16.79 V/V when the input power is around the sensitivity of −60 dBm, and this is 1.7 times higher than that of the conventional envelope detector with the same current and load. The proposed RF-to-DC conversion circuit (WuRx) achieves a sensitivity of about −65.4 dBm based on 45% to 55% duty, dissipating a power of 22 μW from a 1.2 V supply voltage.

Advances in coupled axial turbine and nonaxisymmetric exhaust volute aerodynamics for turbomachinery

2020 ◽  
pp. 095441002096645
Author(s):  
Jie Gao ◽  
Chunde Tao ◽  
Dongchen Huo ◽  
Guojie Wang
Keyword(s):  
Performance Improvement ◽  
High Efficiency ◽  
Three Dimensional ◽  
Great Influence ◽  
Aerodynamic Characteristics ◽  
Turbine Engines ◽  
Gas Turbine Engines ◽  
Axial Turbine ◽  
Flow Interactions ◽  
And Performance

Marine, industrial, turboprop and turboshaft gas turbine engines use nonaxisymmetric exhaust volutes for flow diffusion and pressure recovery. These processes result in a three-dimensional complex turbulent flow in the exhaust volute. The flows in the axial turbine and nonaxisymmetric exhaust volute are closely coupled and inherently unsteady, and they have a great influence on the turbine and exhaust aerodynamic characteristics. Therefore, it is very necessary to carry out research on coupled axial turbine and nonaxisymmetric exhaust volute aerodynamics, so as to provide reference for the high-efficiency turbine-volute designs. This paper summarizes and analyzes the recent advances in the field of coupled axial turbine and nonaxisymmetric exhaust volute aerodynamics for turbomachinery. This review covers the following topics that are important for turbine and volute coupled designs: (1) flow and loss characteristics of nonaxisymmetric exhaust volutes, (2) flow interactions between axial turbine and nonaxisymmetric exhaust volute, (3) improvement of turbine and volute performance within spatial limitations and (4) research methods of coupled turbine and exhaust volute aerodynamics. The emphasis is placed on the turbine-volute interactions and performance improvement. We also present our own insights regarding the current research trends and the prospects for future developments.

scholarly journals The dynamic of body and brain co-evolution

2021 ◽  
pp. 105971232199468
Author(s):  
Paolo Pagliuca ◽  
Stefano Nolfi
Keyword(s):  
Morphological Traits ◽  
The Body ◽  
Morphological Variations ◽  
And Control ◽  
Selection Of

We introduce a method that permits to co-evolve the body and the control properties of robots. It can be used to adapt the morphological traits of robots with a hand-designed morphological bauplan or to evolve the morphological bauplan as well. Our results indicate that robots with co-adapted body and control traits outperform robots with fixed hand-designed morphologies. Interestingly, the advantage is not due to the selection of better morphologies but rather to the mutual scaffolding process that results from the possibility to co-adapt the morphological traits to the control traits and vice versa. Our results also demonstrate that morphological variations do not necessarily have destructive effects on robots’ skills.

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