scholarly journals Computational aerodynamics in architectural siting of the structures of agro-industrial complex

2021 ◽  
Vol 280 ◽  
pp. 03002
Author(s):  
Anton Makhinko ◽  
Nataliia Makhinko
Keyword(s):  
Aerodynamic Characteristics ◽  
Wind Effect ◽  
Cylinder Surface ◽  
Industrial Complex ◽  
Software Module ◽  
Element Mesh ◽  
Computational Aerodynamics ◽  
Sufficient Detail ◽  
Special Relations ◽  
Turbulent Airflow

The article presents study of wind effect on silo parks, which was carried out by computer simulation methods. A special modeling technique was created as a software module for the Ansys Workbench platform. A finite element mesh was developed in accordance with two requirements. Through the use of this mesh, which doesn’t contain needless elements which can be used for simplification of calculations and reduction of execution time, it is possible to describe the turbulent airflow in sufficient detail. The dimensions of all mesh elements are determined by special relations as the functions of the silo diameter and the Reynolds number. The major stage in this investigation was modeling of various options for flowing silos and their groups. As a result of the study, we have obtained aerodynamic characteristics of individual silos as part of silo parks and plotted charts of the distribution of pressure coefficients over the cylinder surface, changing the size of the silos, distances between them and local wind regime. Based on these data, we have drawn a conclusion about the optimal space planning locations of silos for different wind directions. Visualizations of turbulent flow around models at different speeds have also been obtained in this study.

scholarly journals Determination of the aerodynamic characteristics of the tiltrotor with the wingtip-mounted coaxial rotors

2021 ◽  
pp. 108-116
Author(s):  
Sergii Povarov
Keyword(s):  
Vortex Method ◽  
Aerodynamic Characteristics ◽  
Graphical Form ◽  
Maximum Speed ◽  
Basic Model ◽  
Computational Aerodynamics ◽  
Coaxial Rotor ◽  
Aerodynamic Interaction ◽  
Comparison Of The Results ◽  
Coaxial Rotors

The article describes the study of rotor-to-wing aerodynamic interaction for the wingtip-mounted coaxial rotors configuration of the tiltrotor aircraft. The influence of the rotor slipstreams on lift-to-drag ratio characteristic was determined. Obtained results were compared with similar characteristics of the equivalent in thrust conventional single rotor slipstreams impact. Using the computational aerodynamics methods (panel-vortex method) the flow around the tiltrotor model with the wingtip-mounted single and coaxial rotors has been simulated. A study of the basic model configuration with conventional single rotors, based on the technical characteristics of the AgustaWestland AW609 tiltrotor, was conducted. Further researches were conducted for a modified model where single rotors were replaced with equivalent in thrust coaxial rotors. The influence of the rotor slipstreams on the aerodynamic characteristics of the model for both directions of rotors rotation in coaxial combination is considered. Also, the dependence of the maximum lift-to-drag characteristic due to the coaxial rotor diameters change has been determined. The results show that the coaxial rotor slipstreams-to-wing aerodynamic interaction effect is the similar to the effect of conventional single rotor, but less intensive. Comparison of the results showed that a tiltrotor equipped with wingtip-mounted single rotors has approximately 20% greater maximum lift-to-drag characteristic than one equipped with coaxial rotors with the same thrust. However, the use of coaxial rotors allows getting higher maximum speed, when conventional single rotors lose the efficiency significantly. Therefore, it is advisable to conduct further research for the possibility of using coaxial rotors for tiltrotor aircrafts. The research results are presented in graphical form. The obtained data provides a basis for further studies of the described problem, and also will be useful for new tiltrotor design works.

scholarly journals Horizontal Wind Effect on the Aerodynamic Performance of Coaxial Tri-Rotor MAV

2020 ◽  
Vol 10 (23) ◽  
pp. 8612
Author(s):  
Yao Lei ◽  
Yiqiang Ye ◽  
Zhiyong Chen
Keyword(s):  
Wind Tunnel ◽  
Power Consumption ◽  
Aerodynamic Characteristics ◽  
Aerodynamic Performance ◽  
Horizontal Wind ◽  
Wind Effect ◽  
Rotor Speed ◽  
Wind Tunnel Experiments ◽  
Air Vehicle ◽  
Power Loading

The coaxial Tri-rotor micro air vehicle (MAV) is composed of three coaxial rotors where the aerodynamic characteristics of is complicated in flight especially when the wind effect is introduced. In this paper, the hovering performance of a full-scale coaxial Tri-rotor MAV is analyzed with both the simulations and wind tunnel experiments. Firstly, the wind effect on the aerodynamic performance of coaxial Tri-rotor MAV is established with different rotor speed (1500–2300 rpm) and horizontal wind (0–4 m/s). Secondly, the thrust and power consumption of coaxial Tri-rotor (L/D = 1.6) were obtained with low-speed wind tunnel experiments. Furthermore, the streamline distribution, pressure distribution, velocity contour and vortex distribution with different horizontal wind conditions are obtained by numerical simulations. Finally, combining the experiment results and simulation results, it is noted that the horizontal wind may accelerate the aerodynamic coupling, which resulting in the greater thrust variation up to 9% of the coaxial Tri-rotor MAV at a lower rotor speed. Moreover, the aerodynamic performance is decreased with more power consumption at higher rotor speed where the wind and the downwash flow are interacted with each other. Compared with no wind flow, the shape of the downwash flow and the deformation of the vortex affect the power loading and figure of metric accordingly.

scholarly journals Comparison of aerodynamic characteristics of convertible models with single and coaxial schemes of propellers

2020 ◽  
pp. 96-105
Author(s):  
Sergey Povarov
Keyword(s):  
Vortex Method ◽  
Aerodynamic Characteristics ◽  
Graphical Form ◽  
Maximum Speed ◽  
Basic Model ◽  
Computational Aerodynamics ◽  
Coaxial Rotor ◽  
Aerodynamic Interaction ◽  
Comparison Of The Results ◽  
Coaxial Rotors

The article describes the study of rotor-to-wing aerodynamic interaction for the wingtip-mounted coaxial rotors configuration of the tiltrotor aircraft. The influence of the rotor slipstreams on lift-to-drag ratio characteristic was determined. Obtained results were compared with similar characteristics of the equivalent in thrust conventional single rotor slipstreams impact. Using the computational aerodynamics methods (panel-vortex method) the flow around the tiltrotor model with the wingtip-mounted single and coaxial rotors has been simulated. A study of the basic model configuration with conventional single rotors, based on the technical characteristics of the AgustaWestland AW609 tiltrotor, was conducted. Further researches were conducted for a modified model where single rotors were replaced with equivalent in thrust coaxial rotors. The influence of the rotor slipstreams on the aerodynamic characteristics of the model for both directions of rotors rotation in coaxial combination is considered. Also, the dependence of the maximum lift-to-drag characteristic due to the coaxial rotor diameters change has been determined. The results show that the coaxial rotor slipstreams-to-wing aerodynamic interaction effect is the similar to the effect of conventional single rotor, but less intensive. Comparison of the results showed that a tiltrotor equipped with wingtip-mounted single rotors has approximately 20% greater maximum lift-to-drag characteristic than one equipped with coaxial rotors with the same thrust. However, the use of coaxial rotors allows getting higher maximum speed, when conventional single rotors lose the efficiency significantly. Therefore, it is advisable to conduct further research for the possibility of using coaxial rotors for tiltrotor aircrafts. The research results are presented in graphical form. The obtained data provides a basis for further studies of the described problem, and also will be useful for new tiltrotor design works.

scholarly journals THE CALCULATION AERODYNAMIC CHARACTERISTICS OF A HYBRID AEROSTATIC AIRCRAFT

2014 ◽  
pp. 102-111
Author(s):  
Дмитрій Миколайович Зінченко ◽  
Г. Ортамевзи ◽  
А. Рахмати
Keyword(s):  
Aerodynamic Characteristics ◽  
Aerodynamic Design ◽  
Bearing Surface ◽  
Lifting Force ◽  
Computational Aerodynamics ◽  
Key Issues ◽  
New Type ◽  
Different Sources

The article presents a justification layout a new type aircraft with two different sources lifting force – aerodynamic and aerostatic. Consider especially the exploitation aircraft easier to air, identified key issues research, unresolved tasks, formulated the task. Logged matching aerodynamic profile for bearing surface hybrid aircraft, made its adaptation. Using the method of computational aerodynamics the calculation of the flow around the bearing surface, presents an analysis of the results and conclusions and recommendations are given on an aerodynamic design.

Analysis of Dark-Field Images of Disordered Materials

1972 ◽  
Vol 30 ◽  
pp. 560-561
Author(s):  
J. M. Cowley
Keyword(s):  
Amorphous Materials ◽  
Careful Analysis ◽  
Dark Field ◽  
Minimum Diameter ◽  
Statistical Fluctuations ◽  
Bright Spots ◽  
Sufficient Detail ◽  
Random Arrangement ◽  
Diffraction Patterns ◽  
Imaging Conditions

Recently a number of authors have reported detail in dark-field images obtained from diffuse-scattering regions of electron diffraction patterns. Bright spots in images from short-range order diffuse peaks of disordered binary alloys have been interpreted as evidence for the existence of microdomains of ordered lattice or of segragated clusters of one component. Spotty contrast in dark field images of near-amorphous materials has been interpreted as evidence for the existense of microcrystals. Without a careful analysis of the imaging conditions such conclusions may be invalid. Usually the conditions of the experiment have not been specified in sufficient detail to allow evaluation of the conclusions.Elementary considerations show that even for a completely random arrangement of atoms the statistical fluctuations of density will give a spotty contrast with spots of minimum diameter determined by the dark field aperture size and other factors influencing the minimum resolvable distance under darkfield imaging conditions, including fluctuations and drift over long exposure times (resolution usually 10Å or more).

The Shikani HME: A New Tracheostomy Heat and Moisture Exchanger

2020 ◽  
Vol 63 (9) ◽  
pp. 2921-2929
Author(s):  
Alan H. Shikani ◽  
Elamin M. Elamin ◽  
Andrew C. Miller
Keyword(s):  
Ex Vivo ◽  
Moisture Loss ◽  
Speaking Valve ◽  
Time Zero ◽  
In Series ◽  
Turbulent Airflow ◽  
The Difference ◽  
Loss Efficiency ◽  
Heat And Moisture ◽  
Lung Simulation

Purpose Tracheostomy patients face many adversities including loss of phonation and essential airway functions including air filtering, warming, and humidification. Heat and moisture exchangers (HMEs) facilitate humidification and filtering of inspired air. The Shikani HME (S-HME) is a novel turbulent airflow HME that may be used in-line with the Shikani Speaking Valve (SSV), allowing for uniquely preserved phonation during humidification. The aims of this study were to (a) compare the airflow resistance ( R airflow ) and humidification efficiency of the S-HME and the Mallinckrodt Tracheolife II tracheostomy HME (M-HME) when dry (time zero) and wet (after 24 hr) and (b) determine if in-line application of the S-HME with a tracheostomy speaking valve significantly increases R airflow over a tracheostomy speaking valve alone (whether SSV or Passy Muir Valve [PMV]). Method A prospective observational ex vivo study was conducted using a pneumotachometer lung simulation unit to measure airflow ( Q ) amplitude and R airflow , as indicated by a pressure drop ( P Drop ) across the device (S-HME, M-HME, SSV + S-HME, and PMV). Additionally, P Drop was studied for the S-HME and M-HME when dry at time zero (T 0 ) and after 24 hr of moisture testing (T 24 ) at Q of 0.5, 1, and 1.5 L/s. Results R airflow was significantly less for the S-HME than M-HME (T 0 and T 24 ). R airflow of the SSV + S-HME in series did not significant increase R airflow over the SSV or PMV alone. Moisture loss efficiency trended toward greater efficiency for the S-HME; however, the difference was not statistically significant. Conclusions The turbulent flow S-HME provides heat and moisture exchange with similar or greater efficacy than the widely used laminar airflow M-HME, but with significantly lower resistance. The S-HME also allows the innovative advantage of in-line use with the SSV, hence allowing concurrent humidification and phonation during application, without having to manipulate either device.

The export-oriented import substitution potential in the agro-industrial complex of the EAEU

2019 ◽  
pp. 74-89
Author(s):  
Boris A. Kheyfets ◽  
Veronica Yu. Chernova
Keyword(s):  
Global Economy ◽  
Import Substitution ◽  
Industrial Complex ◽  
Important Direction

The paper analyzes the possibilities of improving the Russian policy of import substitution using the potential of the EAEU. A concrete analysis was carried out for the branches of the agro-industrial complex, where the greatest success was achieved in import substitution. There is a need for smart selective import substitution, the most important direction of which is the export-oriented one. This will improve the competitiveness of Russia and the EAEU as a whole in the global economy and will also promote the deepening of mutual ties of the EAEU countries. The main ways of solving this problem are shown.

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