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Wyświetlanie 1-15 z 98
Tytuł:
3D simulation of incompressible flow around a rotating turbulator: Effect of rotational and direction speed
Autorzy:
Zoubai, Elhadi
Laidoudi, Houssem
Tlanbout, Ismail
Makinde, Oluwole Daniel
Powiązania:
https://bibliotekanauki.pl/articles/27312235.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:
rotating
turbulator
straight tube
drag coefficient
power number
laminar
flow
Opis:
This paper presents new results for the dynamic behaviour of fluid around a rotating turbulator in a channel. The turbulator has a propeller form which is placed inside a flat channel. The research was carried out using 3D numerical simulation. The rationale of the experiment was as follows: we put a propeller-turbulator inside a flat channel, and then we insert a water flow inside the channel. The turbulator rotates at a constant and uniform speed. The main points studied here are the effect of the presence of turbulator and its rotational direction on the flow behaviour behind the turbulator. The results showed that the behaviour of flow behind the turbulator is mainly related to the direction of turbulator rotating. Also, the studied parameters affect coefficients of drag force and power number. For example, when the turbulator rotates in the positive direction, the drag coefficient decreases in terms of rotational speed of the turbulator, while the drag coefficient increases in terms of rotational speed when the turbulator rotates in the negative direction.
Źródło:
Archives of Thermodynamics; 2023, 44, 2; 139--157
1231-0956
2083-6023
Pojawia się w:
Archives of Thermodynamics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
CFD Study of Base Drag of the Grot Rocket
Autorzy:
Sahbon, Nezar
Michałów, Maciej
Murpani, Siddharth
Żurawka, Paulina
Kaczmarek, Kacper
Powiązania:
https://bibliotekanauki.pl/articles/36822389.pdf
Data publikacji:
2023
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Lotnictwa
Tematy:
base drag
computational fluid dynamics
rocket aerodynamics
sounding rockets
solid rocket propulsion
Opis:
Propulsion system operation is known to affect the aerodynamic characteristics of rockets. Specifically, the net axial force acting on a rocket in flight cannot be precisely obtained by combining the static thrust with drag values computed for a rocket with an inactive motor. One of the main reasons for this is the influence of motor operation on pressure at the base of the rocket. The aim of this paper is to investigate the effect of motor operation on the aerodynamic parameters of the Grot sounding rocket developed by the Students’ Space Association, Warsaw University of Technology. The study consists of two series of axisymmetrical computational fluid dynamic simulations of flow around the rocket - one with the motor being non-operational and the other with active thrust. In the post-processing phase, the axial force acting on various components of the rocket is computed, with an emphasis on the base and nozzle exit sections. Quantitative and qualitative differences between the cases with and without active thrust are highlighted and discussed. The obtained results are compared to a semi-empirical model found in the literature. Finally, a semi-empirical base drag model is proposed for use in Grot flight simulation.
Źródło:
Transactions on Aerospace Research; 2023, 2 (271); 1-16
0509-6669
2545-2835
Pojawia się w:
Transactions on Aerospace Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Experimental and numerical analysis of vortex generators designed for utility vehicles
Autorzy:
Chidambaram, Ramesh Kumar
Kanna, Rajesh
Gopal, Poomanandan
Arumugam, Senthil Kumar
Powiązania:
https://bibliotekanauki.pl/articles/27312222.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:
vortex generator
pressure coefficient
numerical simulation
drag force
Opis:
The main goal of today’s car designers is to minimize fuel consumption in all possible ways at the same time maintaining the vehicle’s performance as usual. The goal of this work is to study the effect of adding a vortex generator (VG) on the aerodynamics of the vehicle and fuel economy. Both theoretical and experimental works were carried out and the outcomes of the numerical simulations are contrasted with those of the experimental results. A utility vehicle model with a scale ratio of 1:15 was used as a test model. Experimental research has been done on the fluctuation of the coefficient of pressure, dynamic pressure, and coefficients of lift and drag with and without VG on the roof of a utility vehicle. The delta-shaped VG was put to the test both numerically and experimentally. At a velocity of 2.42 m/s, it is observed that the addition of VG can raise the pressure coefficient by about 17%. When compared to the vehicle model without vortex generators, the velocity profile of the ccomputational fluid dynamics analysis shows that at the back end of the vehicle, the wake has been minimized with VG.
Źródło:
Archives of Thermodynamics; 2023, 44, 3; 217--240
1231-0956
2083-6023
Pojawia się w:
Archives of Thermodynamics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Minimization of Energy Consumption of Vortex Devices for Granulation of Materials
Autorzy:
Pavlenko, Anatoliy
Cheilytko, Andrii
Ilin, Sergii
Karpenko, Hanna
Powiązania:
https://bibliotekanauki.pl/articles/27315749.pdf
Data publikacji:
2023
Wydawca:
Politechnika Koszalińska. Wydawnictwo Uczelniane
Tematy:
aerodynamic drag
cyclone
vortex device
pelletising
medium dispersion factor
optimal geometric dimensions
Opis:
The article considers the possibility of efficient energy and environmental use of vortex devices for the granulation of solids. The factors influencing the energy consumption for generating a vortex flow with dispersed solid inclusions are analysed. A mathematical model for calculating the aerodynamic drag of a vortex apparatus in a clean gas flow, which was used in computer modelling, is presented. The main dependencies for determining the influence of the geometric dimensions of the vortex on its aerodynamic drag are also given. An analytical solution to the problem of minimising the aerodynamic drag of a vortex apparatus during the movement of a dispersed medium is considered. The forces acting on the particles in the cyclone chamber during interaction with the gas are analysed. In this paper, a general method for calculating the parameters of cyclone-vortex devices for dispersed media using the basic equations of hydrodynamics and gas dynamics is developed. The solution approach used in this paper can be extended to other vortex devices not considered in this work.
Źródło:
Rocznik Ochrona Środowiska; 2023, 25; 198--207
1506-218X
Pojawia się w:
Rocznik Ochrona Środowiska
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Slow flow of couple stress fluid past a cylinder embedded in a porous medium: slip effect
Autorzy:
Sarkar, Priya
Madasu, Krishna Prasad
Powiązania:
https://bibliotekanauki.pl/articles/38911649.pdf
Data publikacji:
2023
Wydawca:
Instytut Podstawowych Problemów Techniki PAN
Tematy:
couple stress fluid
cylinder
Brinkman’s equation
saturated porous medium
slip coefficients
drag force
Opis:
An analytical study for the creeping flow of a couple stress fluid past a cylinder embedded in a porous medium is presented using the slip condition. The uniform flow is considered far away from a cylinder. The boundary conditions used are zero couple stress and tangential slip conditions. The modified Bessel functions represent the stream function (the velocity). The drag exerted on a solid cylinder immersed in a porous medium is derived. The impacts of the couple stress, permeability, and slip parameters on the normalized drag force are presented graphically. The drag forces of well-known exceptional cases are reduced. The drag force is a decreasing function of the permeability and couple stress parameters and an increasing function of the slip parameter.
Źródło:
Engineering Transactions; 2023, 71, 4; 537-551
0867-888X
Pojawia się w:
Engineering Transactions
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Studies on the flame structure and drag of a combusting droplet group
Autorzy:
Zhou, Lixing
Li, Ke
Sun, Ting
Powiązania:
https://bibliotekanauki.pl/articles/24202455.pdf
Data publikacji:
2023
Wydawca:
Polskie Towarzystwo Naukowe Silników Spalinowych
Tematy:
droplet-group combustion
large-eddy simulation
flame structure
drag force
spalanie kropelkowe
modelowanie wielkowirowe
struktura płomienia
siła oporu
Opis:
Droplet combustion has been studied by experiments and numerical simulation for many years, and most of studies were done about single droplets. As for droplet groups, some theoretical and experimental studies were reported, but less of numerical studies. One of the important characteristics is the drag of combusting droplets, which is closely related to flame structure，and is a sub-model in numerical simulation of spray combustion. There are contradictory research results for the drag of combusting droplets. In the present paper, large-eddy simulation (LES) is used to study the flame structure and drag of a combusting ethanol-droplet group. The results show that there are three combustion modes: fully-enveloped flame, partially-enveloped flame and wake flame in a droplet group, leading to the change of the drag with inlet velocities. It is found that the drag of droplets in the group is much smaller than that of a non-combusting particle in isothermal flows.
Źródło:
Combustion Engines; 2023, 62, 2; 3--8
2300-9896
2658-1442
Pojawia się w:
Combustion Engines
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An analytical study of couple stress fluid through a sphere with an influence of the magnetic field
Autorzy:
Krishna Prasad, Madasu
Sarkar, Priya
Powiązania:
https://bibliotekanauki.pl/articles/2202037.pdf
Data publikacji:
2022
Wydawca:
Politechnika Częstochowska. Wydawnictwo Politechniki Częstochowskiej
Tematy:
creeping flow
sphere
magnetic effect
couple stress fluid
drag
przepływ pełzający
kula
efekt magnetyczny
Opis:
The present work concerns to study of the steady, axisymmetric slow flow of couple stress fluid through a rigid sphere in the transverse magnetic field. Boundary conditions on the sphere surface are the zero couple stress condition and tangential slip condition. The stream function, vorticity vector, and pressure term are obtained. The drag acting on the sphere in the presence of MHD is calculated. Here, we graphically represented the Hartmann number, couple stress, and slip parameters effect on the drag coefficient. Some well-known results of the drag are deduced.
Źródło:
Journal of Applied Mathematics and Computational Mechanics; 2022, 21, 3; 99--110
2299-9965
Pojawia się w:
Journal of Applied Mathematics and Computational Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Couple stress fluid past a sphere embedded in a porous medium
Autorzy:
Madasu, Krishna Prasad
Sarkar, Priya
Powiązania:
https://bibliotekanauki.pl/articles/2065761.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
sphere
couple stress fluid
saturated porous medium
Brinkman’s equation
drag force
kula
równanie Brinkmana
siła tarcia
Opis:
This paper concerns the analytical investigation of the axisymmetric and steady flow of incompressible couple stress fluid through a rigid sphere embedded in a porous medium. In the porous region, the flow field is governed by Brinkman’s equation. Here we consider uniform flow at a distance from the sphere. The boundary conditions applied on the surface of the sphere are the slip condition and zero couple stress. Analytical solution of the problem in the terms of stream function is presented by modified Bessel functions. The drag experienced by an incompressible couple stress fluid on the sphere within the porous medium is calculated. The effects of the slip parameter, the couple stress parameter, and permeability on the drag are represented graphically. Special cases of viscous flow through a sphere are obtained and the results are compared with earlier published results.
Źródło:
Archive of Mechanical Engineering; 2022, LXIX, 1; 5--19
0004-0738
Pojawia się w:
Archive of Mechanical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Experimental study on Ahmed’s body drag coefficient
Autorzy:
Wysocki, Dominik
Szymanek, Arkadiusz
Powiązania:
https://bibliotekanauki.pl/articles/2133935.pdf
Data publikacji:
2022
Wydawca:
Uniwersytet Warmińsko-Mazurski w Olsztynie
Tematy:
Ahmed body
aerodynamics
wind tunnel
drag coefficient
boundary layer
Opis:
The work presents an experimental designation of the aerodynamic drag coefficient for two configurations of the Ahmed body model, with slant angle of 25° and with the inactive synthetic jet generator. When analyzing the aerodynamic drag of vehicles, most authors focus on higher Reynolds numbers, describing lower values only by designated trend lines. Which is why the main contribution of this experimental work was to designate the Ahmed’s body drag coefficient for low Reynolds numbers and to verify the obtained results with other authors experiments especially with the trend lines for Reynolds number in the range 0,35x105 – 1,8x105. For data taken from the literature, it can be seen that the value of the drag coefficient for the Ahmed body model decreases when the Reynolds number increases. The results obtained during the experiment show the opposite tendency.
Źródło:
Technical Sciences / University of Warmia and Mazury in Olsztyn; 2022, 25(1); 87--105
1505-4675
2083-4527
Pojawia się w:
Technical Sciences / University of Warmia and Mazury in Olsztyn
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Investigating the effect of insoluble additives type on the drag reduction performance in a crude oil turbulent flow system
Autorzy:
Mahmood, Wafaa Kamil
Abdulbari, Hayder A.
Laft, Asaad H.
Powiązania:
https://bibliotekanauki.pl/articles/2142862.pdf
Data publikacji:
2022
Wydawca:
Centrum Badań i Innowacji Pro-Akademia
Tematy:
drag reduction
turbulence
insoluble additives
crude oil
powder
redukcja oporu
turbulencja
dodatki nierozpuszczalne
ropa naftowa
proszek
Opis:
In the present work, the effect of three insoluble additives densities on reducing the drag of crude oil was investigated. The objective of the present work is to evaluate the effect of the insoluble additive’s densities on their drag reduction efficiency in hydrocarbon flow medium. Three powders with different densities are chosen, namely carbon powder, glass powder, and copper powder, with a density of 1710 kg/m3 , 2550 kg/m3 , and 8950 kg/m3 , respectively. The turbulence flow environment was created in a custom-made rotating disc apparatus with a maximum rotation speed of 300 rpm. To evaluate the effect of the powder density, the particle's size was chosen to be 100 µm. All the solutions were tested at the exact operating conditions with a rotation speed ranging between 200 to 2200 rpm. The experimental results showed a clear effect of the powder density on the drag reduction performance. The glass powders showed the highest drag reduction effect, while the copper and carbon powders were lower. The effect of the degree of turbulence on the drag reduction performance of the powders was clear, where the interaction between the powders and the turbulence structures (eddies) governed the turbulence-suppression efficiency of the additives.
Źródło:
Acta Innovations; 2022, 43; 44-53
2300-5599
Pojawia się w:
Acta Innovations
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical analysis and optimization of a winglet sweep angle and winglet tip chord for improvement of aircraft flight performance
Autorzy:
Al-Khafaji, Ali J. Dawood
Panatov, Gennady S.
Boldyrev, Anton S.
Powiązania:
https://bibliotekanauki.pl/articles/2096195.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Polskie Towarzystwo Diagnostyki Technicznej PAN
Tematy:
lift
drag
lift coefficient
drag coefficient
aircraft wing
winglet
angle of attack
sweep angle
SOLIDWORKS
CFD
ANSYS FLUENT
współczynnik siły nośnej
współczynnik oporu
skrzydło samolotu
skrzydełko aerodynamiczne
kąt natarcia
SolidWorks
ANSYS Fluent
Opis:
In this paper, a study of the effect of winglet sweep angle and winglet tip chord of the aircraft wing on the aerodynamics performances and how to improve it are carried out, assuming Cant angle 60°, winglet height = 3.5 m, Toe angle = -5°, and Twist angle = +5°. Different sweep angles tested (-25°, -15°, 0°, +15°, +25°, +35°, and +45°) and winglet tip chord (0.25, 0.375, and 0.5 m). Four Angle of attack is presented (0°, 3°, 6°, and 9°). The aerodynamics properties of the wing were measured in terms of calculated lift to drag ratio to decide which wing has a high value of lift and lower drag. All models of a wing (eighty-four models) are drawn for 3D using the SOLIDWORKS program. Boeing 737-800 wing dimensions were used. All models of a wing were analyzed using ANSYS FLUENT. The results showed that sweep angle and winglet tip chord of the winglet by changing their configuration can improve aerodynamic performance for various attack angles. The maximum value of the lift to drag ratio was obtained with a sweep angle -15°, winglet tip chord 0.375m, and angle of attack 3°.
Źródło:
Diagnostyka; 2022, 23, 2; art. no. 2022210
1641-6414
2449-5220
Pojawia się w:
Diagnostyka
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Shape optimization of a submerged 2D hydrofoil and improvement of its lift-to-drag ratio using CFDbased mesh morphing-adjoint algorithm
Autorzy:
Nazemian, Amin
Ghadimi, Parviz
Ghadimi, Aliakbar
Powiązania:
https://bibliotekanauki.pl/articles/24202520.pdf
Data publikacji:
2022
Wydawca:
Akademia Morska w Szczecinie. Wydawnictwo AMSz
Tematy:
NACA0012 hydrofoil
free surface
lift-to-drag ratio
Ansys-Fluent
mesh morphing
adjoint solver
Opis:
Hydrofoils are utilized as instruments to improve the hydrodynamic performance of marine equipment. In this paper, the motion of a 2D NACA0012 hydrofoil advancing in water near the free surface was simulated, and a mesh morphing-adjoint based optimizer was used to maximize its lift-to-drag ratio. Ansys-Fluent was used as a CFD solver, and a mesh-morphing tool was used as a geometry reconstruction tool. Furthermore, the Adjoint solver was applied to evaluate the sensitivities of the objective function to all solution variables. Defined control points around the geometry are design variables that move in an appropriate direction through shape sensitivity. The computational results were validated against available experimental data and published numerical findings. Subsequently, different hydrodynamic characteristics of the optimized hydrofoil were compared to those of the original model at different angles of attack of 3, 3.5, 4, 4.5, 5, 5.5, 6, and 6.5°, and optimized shapes were determined. It was observed that the shape of the optimized hydrofoil was totally dependent on the angle of attack, which produced different lift-to-drag ratios. It is also seen that among higher angles of attack at which improvement in the L/D ratio became steady, the drag coefficient was the lowest at 5°. Therefore, it can be concluded that the appropriate angle of attack for a hydrofoil installation on the ship hull is 5°. Further investigation was conducted concerning the evolution of shape optimization, sensitivity analysis, free surface elevation, flow characteristics, and hydrodynamic performance of the hydrofoil at a 5° angle of attack.
Źródło:
Zeszyty Naukowe Akademii Morskiej w Szczecinie; 2022, 70 (142); 27--40
1733-8670
2392-0378
Pojawia się w:
Zeszyty Naukowe Akademii Morskiej w Szczecinie
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Two-dimensional analogies to the deformation characteristics of a falling droplet and its collision
Autorzy:
Rafi, Abid Hasan
Haque, Mohammad Rejaul
Ahmed, Dewan Hasan
Powiązania:
https://bibliotekanauki.pl/articles/2065760.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
droplet
freefall
spreading
drag force
kropelka
swobodny spadek
siła tarcia
Opis:
The present study investigates the 2D numerical analogies to the changes of the droplet shapes during the freefall for a wide range of droplet sizes through the stagnation air. The freefall velocity, shape change due to frictional force during free-fall is studied for different considered cases. With the elapse of time, a droplet with a larger initial diameter is changing its original shape more compared to droplets with a smaller diameter. In addition, the spreading of the droplet during the freefall seems more rapid for the larger-diameter droplet. When a droplet with an initial diameter of 15 mm starts to fall with gravitational force, the diameter ratio is decreasing for droplets with higher density and surface tension while droplets having lower density and surface tension show a diameter ratio greater than one. The spreading and splashing of the droplet on a solid surface and liquid storage at the time of impact are much influenced by the freefall memories of the droplet during the freefall from a certain height. These freefall memories are influenced by the fluid properties, drag force, and the freefall height. However, these freefall memories eventually regulate the deformation of the droplet during the freefall.
Źródło:
Archive of Mechanical Engineering; 2022, LXIX, 1; 21--43
0004-0738
Pojawia się w:
Archive of Mechanical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Aerodynamic characteristics of a straight wing with a spiroid wingtip device
Charakterystyka aerodynamiczna skrzydła prostego z urządzeniem spiroidalnym na końcówce skrzydła
Autorzy:
Kravchenko, Igor F.
Loginov, Vasyl V.
Ukrainets, Yevgene O.
Hluschenko, Pavlo A.
Powiązania:
https://bibliotekanauki.pl/articles/36439637.pdf
Data publikacji:
2021
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Lotnictwa
Tematy:
lift drag ratio
flight range
flight duration
unmanned aerial vehicles
aerodynamic configuration
spiroid wingtip devices
spiroidalne końcówki skrzydeł
bezzałogowe statki powietrzne
doskonałość aerodynamiczna
zasięg lotu
długotrwałość lotu
konfiguracja aerodynamiczna
Opis:
Spiroid wingtip devices (WD) offer a promising way of improving the lift drag ratio of UAVs, but may on the other hand lead to negative aerodynamic interference of the wing with the WD and deterioration of the aerodynamic characteristics as compared to a wing without the WD. Determining the influence of the geometric parameters of a spiroid WD on aerodynamic wing characteristics, however, remains an understudied field. In our study, we investigated the influence of the following geometrical parameters on wing aerodynamic characteristics with WD: area, radius, camber angle, constriction, and pitch of the spiroid. We found that the positive effect of the WD is present at a relative radius r̅ > 0.05, as well as with an increase in the lift coefficient CL as a result of an increase in the proportion of inductive resistance. For example, with the Reynolds number Re = 2.1×105 for a rectangular wing with an aspect ratio θ = 5.12 equipped with a spiroid WD with r̅ = 0.15 the quality gain is almost 10% at CL = 0.5, and at CL = 0.7 is almost 20% and at CL = 0.7 - almost 20% compared to a wing without WD. Moreover, we found that a change in the camber angle WD θ provides an increase in the derivative of the lift coefficient with respect to the angle of attack in the range from θ = 0° to θ = 130°. By changing the camber angle, it is possible to increase the lift drag ratio of the layout up to 7.5% at θ = 90° compared to θ = 0° at the Reynolds number Re = 2.1×105. From the point of view of ensuring maximum lift drag ratio and minimum inductive drag, the angle θ = 90° is the most beneficial.
Spiroidalne końcówki skrzydeł (wingtip devices, WD) stanowią obiecującą metodę na poprawę współczynnika oporu aerodynamicznego bezzałogowych statków powietrznych (UAVs). Jednak z drugiej strony mogą prowadzić do negatywnej interferencji aerodynamicznej skrzydła z spiroidalną końcówką i pogorszenia charakterystyk aerodynamicznych w porównaniu do skrzydła bez końcówki. Określenie wpływu parametrów geometrycznych spiroidalnej końcówki na charakterystyki aerodynamiczne skrzydła pozostaje jednak nadal słabo zbadanym zagadnieniem. W pracy tej zbadano wpływ następujących parametrów geometrycznych na charakterystyki aerodynamiczne skrzydła z WD: powierzchnia, promień, kąt pochylenia, przewężenie i rzut spiroida. Stwierdziliśmy, że pozytywny wpływ WD występuje przy promieniu względnym r̅ > 0,05, jak również przy wzroście współczynnika siły nośnej CL w wyniku wzrostu udziału oporu indukowanego. Przykładowo, przy liczbie Reynoldsa Re = 2,1×105 dla skrzydła prostokątnego o wydłużeniu θ = 5,12 wyposażonego w spiroidalną końcówkę WD r̅ = 0,15 przyrost jakości wynosi przy CL = 0,5 prawie 10%, a przy CL = 0,7 prawie 20% i przy CL = 0,7 - prawie 20% w stosunku do skrzydła bez WD. Ponadto stwierdziliśmy, że zmiana kąta pochylenia WD θ zapewnia wzrost pochodnej współczynnika nośności względem kąta natarcia w zakresie od θ = 0° do θ = 130°. Poprzez zmianę kąta pochylenia możliwe jest zwiększenie doskonałości aerodynamicznej układu do 7,5% przy θ = 90° w stosunku do θ = 0° przy liczbie Reynoldsa Re = 2,1×105. Z punktu widzenia zapewnienia maksymalnej doskonałości aerodynamicznej i minimalnego oporu indukowanego kąt θ = 90° jest najkorzystniejszy.
Źródło:
Transactions on Aerospace Research; 2021, 2 (263); 46-62
0509-6669
2545-2835
Pojawia się w:
Transactions on Aerospace Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Determination of the aerodynamic drag of pneumatic life rafts as a factor for increasing the reliability of rescue operations
Autorzy:
Jachowski, Jacek
Książkiewicz, Edyta
Szwoch, Izabela
Powiązania:
https://bibliotekanauki.pl/articles/1955588.pdf
Data publikacji:
2021
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
life raft
simulation of drag force
leeway
computational fluid dynamics CFD
Opis:
Ensuring the safety of ship crews at sea is of the utmost importance. Life rafts are one of the basic components of any seagoing vessel and ensuring their stability is an important component of maritime research. This study concerns the determination of the aerodynamic drag coefficients of pneumatic life rafts in a full range of wind speed and directions. The drag coefficients are based on full-scale experimental studies and numerical calculations (computational fluid dynamics) carried out with Flow-3D software. Two types of life rafts are analysed in the numerical simulations, namely, a non-deformed raft and a raft deformed under the influence of wind pressure at a given flow velocity. The shape of the deformed pneumatic life raft is recreated on the basis of photographic documentation from experimental studies. The results of the numerical calculations are verified on the basis of full-scale flow experiments carried out at the Low Speed Wind Tunnel T-3 Laboratory at the Institute of Aviation in Warsaw. This study shows that there is a dependence of aerodynamic drag on the degree of deformation of the above-water part of the life raft, as well as the angle of the raft setting to the wind. In real water conditions, this angle depends mainly on the anchor point of the drift anchor and therefore should be considered at the design stage, which will directly reduce the wind leeway of the raft.
Źródło:
Polish Maritime Research; 2021, 3; 128-136
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-15 z 98

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