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Wyszukujesz frazę "computational fluid dynamics" wg kryterium: Temat


Tytuł:
CFD and experimental investigation of the impact of dimensional modifications on wind pressure coefficient distribution
Analiza CFD oraz metody eksperymentalne w badaniach wpływu modyfikacji wymiarów na rozkład współczynnika parcia wiatru
Autorzy:
Ali, Ramjan
Anam, Iftekhar
Yoshida, Shigeo
Powiązania:
https://bibliotekanauki.pl/articles/27322564.pdf
Data publikacji:
2023
Wydawca:
Politechnika Świętokrzyska w Kielcach. Wydawnictwo PŚw
Tematy:
Computational Fluid Dynamics
wind pressure coefficient
building dimensions
windward
leeward
side ratio
obliczeniowa dynamika płynów
współczynnik ciśnienia wiatru
strona nawietrzna
strona zawietrzna
proporcje boków
Opis:
The sway of tall buildings in the wind is a fascinating and crucial consideration for professionals in the structural, environmental, and architectural fields. Previous research has related wind pressure to building load and natural ventilation, but few studies have looked at how building dimensions impact wind pressure. This study examined wind pressure coefficient distributions within and around several rectangular-shaped high-rise buildings using experimental and computational fluid dynamics approaches. The height-to-width ratio and height-to-thickness (length) ratio significantly affected the wind characteristics of buildings. The windward side with a narrower width experienced higher wind pressure, while the larger leeward side experienced a more negative wind effect. Wind pressure coefficient distribution varies with decrease in the side ratio. However, the side ratio of the building had little influence on positive wind pressure at wind incidence angle of 0°, which was a surprising finding. Pressure coefficients were evaluated and compared with standards by measuring fluctuating wind pressures at pressure points on all surfaces of models, and then calculating the mean, maximum, minimum, and r.m.s. values of these coefficients.
Kołysanie się wysokich budynków pod wpływem wiatru jest fascynującym i kluczowym zagadnieniem dla specjalistów w dziedzinie konstrukcji, ochrony środowiska i architektury. W niniejszym artykule zbadano rozkłady współczynnika parcia wiatru wewnątrz i wokół kilku budynków wysokich o kształcie prostokąta, stosując metody eksperymentalne i numeryczne (obliczeniowa dynamika płynów). Stosunek wysokości budynku do jego szerokości oraz stosunek wysokości budynku do jego grubości (długości) miały znaczący wpływ na charakterystykę oddziaływania wiatru. Większe ciśnienie wiatru odnotowano po stronie nawietrznej o mniejszej szerokości, podczas gdy na większej ścianie od strony zawietrznej oddziaływanie wiatru było bardziej negatywne. Rozkład współczynnika parcia wiatru zmienia się wraz ze spadkiem stosunku boków. Jednak stosunek ten miał niewielki wpływ na dodatnie ciśnienie wiatru przy kierunku wiatru 0°, co było zaskakującym odkryciem. Współczynniki ciśnienia zostały ocenione i porównane z podejściem normowym poprzez pomiar zmiennego ciśnienia wiatru w punktach parcia na wszystkich powierzchniach modeli, a następnie obliczenie średnich, maksymalnych, minimalnych i średnich kwadratowych wartości tych współczynników.
Źródło:
Structure and Environment; 2023, 15, 4; 208--216
2081-1500
Pojawia się w:
Structure and Environment
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:
Evaluation of wind effects on buildings using design codes and numerical wind tunnel tests
Ocena wpływu wiatru na budynki z wykorzystaniem norm projektowych i testów numerycznych w metodzie tunelu aerodynamicznego
Autorzy:
Hossain, Imam
Islam, Jahidul
Amin, Al
Powiązania:
https://bibliotekanauki.pl/articles/27314901.pdf
Data publikacji:
2023
Wydawca:
Politechnika Świętokrzyska w Kielcach. Wydawnictwo PŚw
Tematy:
wind load analysis
wind tunnel test
wind simulation
reinforced cement concrete structure
computational fluid dynamics
Bangladesh National Building Code
analiza obciążenia wiatrem
test w tunelu aerodynamicznym
symulacja oddziaływania wiatru
konstrukcja żelbetowa
obliczeniowa dynamika płynów
bangladeska krajowa norma budowlana
Opis:
The evaluation of wind effect on the regular shape and simple diaphragm buildings and structures due to wind load has been calculated by several international codes and standards where wind gust nature and dynamic effect could not capture. Bangladesh National Building Code (BNBC) provides the tools for engineers to calculate the wind pressures for the design of a regular-shaped structure with a height to width ratio of less than 5.0, a simple diaphragm, and no unusual geometrical irregularity. If these conditions do not satisfy a wind tunnel testing is required. In this study, a comparative study between two codes in Bangladesh (BNBC-2006 and BNBC-2020), and wind tunnel test results are conducted. An investigation is carried out on four typical buildings with variable heights located within Dhaka, Bangladesh. A computational fluid dynamics (CFD) program RWIND is used to calculate the wind loads on buildings and are compared with those obtained by Bangladesh National Building Codes. Storey shear of four different building models is compared. Between BNBC-2006 and BNBC-2020, there is up to a 53% difference in storey shear. Whereas, up to 30% variation in storey shear is observed between the numerical wind tunnel test data and the data calculated using the BNBC-2020 equations. Finally, this study will help in improving BNBC code provisions for wind load calculations.
Kalkulację wpływu wiatru na budynki i budowle o regularnych kształtach i prostych konstrukcjach pod obciążeniem wiatrem przedstawiono w kilku normach międzynarodowych, w których jednak nie uwzględniono charakteru podmuchów wiatru i efektu dynamicznego. Bangladeska Krajowa Norma Budowlana (BNBC) zapewnia inżynierom narzędzia do obliczania ciśnienia wiatru przy projektowaniu konstrukcji o regularnym kształcie, o stosunku wysokości do szerokości mniejszym niż 5,0, prostej konstrukcji oraz bez nietypowych nieregularności geometrycznych. Jeśli warunki te nie są spełnione, wymagane jest przeprowadzenie testów w tunelu aerodynamicznym. W niniejszym opracowaniu przeprowadzono badanie porównawcze między dwiema normami obowiązującymi w Bangladeszu (BNBC-2006 i BNBC-2020) oraz wynikami testów w tunelu aerodynamicznym. Badanie przeprowadzono na czterech typowych budynkach o różnej wysokości zlokalizowanych w Dhace w Bangladeszu. Program RWIND do obliczeń i symulacji dynamiki płynów (CFD) został wykorzystany do obliczenia obciążeń wiatrem na budynkach i porównany z wynikami uzyskanymi według bangladeskich norm budowlanych. Porównano ścinanie kondygnacji czterech różnych modeli budynków. W tym względzie różnice pomiędzy BNBC-2006 i BNBC-2020 wynoszą do 53%. Natomiast między danymi z numerycznego testu w tunelu aerodynamicznym a danymi obliczonymi przy użyciu równań BNBC-2020 zaobserwowano do 30% różnic w odniesieniu do ścinania kondygnacji. Badanie to pomoże też ulepszyć przepisy norm BNBC dotyczące obliczeń obciążenia wiatrem.
Źródło:
Structure and Environment; 2023, 15, 2; 73--81
2081-1500
Pojawia się w:
Structure and Environment
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Experimental and numerical analyses of airflow around two cylinders angled to the direction of wind
Autorzy:
Padewska-Jurczak, Agnieszka
Szczepaniak, Piotr
Walentyński, Ryszard
Powiązania:
https://bibliotekanauki.pl/articles/2204499.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
wind action
CFD
computational fluid dynamics
FVM
finite volume method
ANSYS Fluent
wind tunnel test
water slide
działanie wiatru
obliczeniowa dynamika płynów
metoda objętości skończonych
testy w tunelu aerodynamicznym
zjeżdżalnia wodna
Opis:
The analyses aim to determine aerodynamic force coefficients in the case of airflow around two smooth or rough cylinders positioned at different angles to the direction of wind velocity. Such systems, for instance, may be part of a tubular water slide. The results were compared with the values of the interference coefficient of the cylinders arranged in a row included in Eurocode EN 1991 part 4. The aerodynamic forces of the cylinder systems were determined on the basis of experimental tests conducted in a wind tunnel. To verify the above results, CFD (computational fluid dynamics) simulations were prepared. An important observation is that for the angle of yaw β = 0◦, the negative component of the lift force (lateral) fy is shown, while for the other cases, the situation is opposite and the lateral force points outside the gap (upward). The second is that the results of aerodynamic drag for rough cylinders arranged in a row and calculated according to EN 1991 part 4 may be underestimated. The flow around the pair of smooth cylinders is quite different from that of the rough ones, because during the experiment the first falls into the critical flow regime, while the second has supercritical characteristics.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2023, 71, 1; art. no. e144578
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Investigation into the Flow of Gas-Solids during Dry Dust Collectors Exploitation, as Applied in Domestic Energy Facilities – Numerical Analyses
Autorzy:
Maćkowiak, Albert
Kostrzewski, Mariusz
Bugała, Artur
Chamier-Gliszczyński, Norbert
Bugała, Dorota
Jajczyk, Jarosław
Woźniak, Waldemar
Dombek, Grzegorz
Nowak, Karol
Powiązania:
https://bibliotekanauki.pl/articles/28086943.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Polskie Naukowo-Techniczne Towarzystwo Eksploatacyjne PAN
Tematy:
the efficiency of dust extraction
energy consumption
multi-phase flow transport
technological transport
computational fluid dynamics
dust collector
Opis:
The paper presents the results related to the simulation of dust-separating tangential cyclones: single cyclones of various geometries, and an axial multi-cyclone with fixed geometries and components. Its goal was to apply low-cost analyses for cyclones in industrial realization. Therefore, the presented research was applied with simulation methodology as a problem of Computational Fluid Dynamics. The models were analyzed using SolidWorks Flow Simulation software. The presented dust collectors are real-life objects, applied in industrial facilities. For a multi-cyclone, the increase in the number of blades, from 5 to 8, together with the change in the angle of a blade’s pitch i.e., 30° and 45°, resulted in dust concentration along the internal walls from just 10% for 5 blades up to c.a. 37.5% for 6 blades, and c.a. 50% for 8 blades, whereas the dust concentration in the device’s central part equals c.a. 20% for the last option. The model validation draws attention to the potential applicability of the software in flow issues alongside common and more complex numerical environments.
Źródło:
Eksploatacja i Niezawodność; 2023, 25, 4; art. no. 174095
1507-2711
Pojawia się w:
Eksploatacja i Niezawodność
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Longitudinal movement modeling and simulation for hybrid underwater glider
Autorzy:
Latifah, Ayu
Ramelan, Agus
Lubis, Dini Hariani Fitri
Trilaksono, Bambang Riyanto
Hidayat, Egi Muhammad Idris
Powiązania:
https://bibliotekanauki.pl/articles/2174482.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Polskie Towarzystwo Diagnostyki Technicznej PAN
Tematy:
hybrid underwater glider
longitudinal motion
nonlinear model
MATLAB/Simulink
computational fluid dynamics
hybrydowy szybowiec podwodny
ruch wzdłużny
model nieliniowy
numeryczna mechanika płynów
Opis:
An autonomous underwater vehicle is a vehicle that can move in water, which is also known as an unmanned undersea vehicle. One type is the hybrid underwater glider where the vehicle is designed in such a way that it is able to carry out missions in the water with less power consumption so that it can last a long time in carrying out missions. In this research, a mathematical design is carried out in the form of a nonlinear model with the aim of being able to produce a model in the longitudinal movement of the HUG vehicle which will be tested limited to a simulation using the MATLAB/Simulink program. The parameters used in the model for this longitudinal movement are obtained by the computational fluid dynamics method so that it has been simulated with various movements according to the mission of the vehicle. In the simulation, input is given in the form of variations in the value of the actuator force to be able to carry out movements according to the mission and the simulation is open loop so that the vehicle's response is in the form of position and speed of translation and rotation.
Źródło:
Diagnostyka; 2023, 24, 1; art. no. 2023106
1641-6414
2449-5220
Pojawia się w:
Diagnostyka
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A CFD Study of the Aerodynamic Characteristics of Twardowsky and FOK Rockets
Autorzy:
Sahbon, Nezar
Murpani, Siddharth
Michałów, Maciej
Miedziński, Dariusz
Sochacki, Mateusz
Powiązania:
https://bibliotekanauki.pl/articles/36452599.pdf
Data publikacji:
2022
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Lotnictwa
Tematy:
computational fluid dynamics
sounding rockets
aerodynamics
modeling
Opis:
Stability and performance are crucial characteristics for aerospace vehicles. The ability to investigate the aerodynamics and performance of rockets gives an insight into their stability before flight and the potential for design and performance enhancements. For the past 13 years, the Rocketry Division within the students’ Space Association of Warsaw University of Technology has been developing sounding rockets of different designs and mission profiles. Two rockets have been chosen for the CFD (Computational Fluid Dynamics) campaigns, FOK and Twardowsky. This paper describes the mathematical model of aerodynamic loads used by the Division for sounding rocket simulation, followed by CFD campaigns for the two rockets. The results of the CFD analysis are then used to calculate the rockets’ aerodynamic derivatives according to a previously defined mathematical model.
Źródło:
Transactions on Aerospace Research; 2022, 1 (266); 35-58
0509-6669
2545-2835
Pojawia się w:
Transactions on Aerospace Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A review of the design and control using computational fluid dynamics of gasoline direct injection engines
Autorzy:
Ali, Mohammed Qasim
Mohamad, Barhm
Powiązania:
https://bibliotekanauki.pl/articles/2096202.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Polskie Towarzystwo Diagnostyki Technicznej PAN
Tematy:
computational fluid dynamics
engine emissions
optimization
gasoline direct injection
combustion modelling
injector spray pattern
numeryczna mechanika płynów
optymalizacja
bezpośredni wtrysk benzyny
Opis:
This paper explores the role of the computational fluid dynamics (CFD) modeling technique in the design, regulation, and production of the gasoline direct injection (GDI) engine combustion system through literature reviews. It begins with a brief analysis of injector technologies and the effect of spray characteristics on the optimization of the combustion system. The key challenges of optimizing a homogeneous-charge GDI combustion system are the enhancement of volumetric performance and homogeneity of fuel-air mixing with reduced wetting of surface fuel and the improvement of power output. Most of the calculations focused on dynamic mesh strategy to manage moving geometry varied from case to case. The techniques of the methods varied. During the opening event of a GDI gasoline-injector for automotive applications, the findings of the literature indicate the primary fuel atomization.
Źródło:
Diagnostyka; 2022, 23, 3; art. no. 2022306
1641-6414
2449-5220
Pojawia się w:
Diagnostyka
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Aeroacoustic analysis based on FW–H analogy to predict low-frequency in-plane harmonic noise of a helicopter rotor in hover
Autorzy:
Suresh, T.
Szulc, O.
Flaszynski, P.
Powiązania:
https://bibliotekanauki.pl/articles/38695686.pdf
Data publikacji:
2022
Wydawca:
Instytut Podstawowych Problemów Techniki PAN
Tematy:
Lighthill’s analogy
Farassat’s formulation
blade element momentum theory
computational aeroacoustics
computational fluid dynamics
thickness noise
monopole
loading noise
dipole
Opis:
The integral formulation of the Ffowcs-Williams and Hawkings (FW–H) analogy, developed by Farassat (known as Farassat’s formulation 1A), is implemented to study the sound generation and propagation of rotating slender bodies. The general post-processing numerical code utilizes the linear acoustic theory to predict the thickness and loading noise terms for bodies in subsonic motion. The developed numerical code is validated for elementary acoustic sources (rotating monopole and dipole) against analytical solutions. The validated code is then applied for prediction of lowfrequency in-plane harmonic noise (LF-IPH) of a model helicopter rotor of Sargent and Schmitz in a low-thrust hover with full-scale tip Mach number. The required loading distribution of the rotor blade is obtained with CFD (RANS) and Blade Element Momentum Theory (BEMT) methods and also validated against literature data. The developed acoustic code, supplemented by CFD and BEMT loading analyses, allows for a detailed comparison (thickness and loading, near- and far-field, etc.) of the LFIPH noise of a helicopter rotor in both, time and frequency domains. The predicted (FW–H) acoustic signals are compared not only with the reference code solutions, but also with the experimental data. Moreover, the paper quantifies the impact of computational grid density and time-step size (used by CFD and FW–H codes) on the final solution accuracy. Additionally, a simplified analytical code is developed (based on elementary dipole solutions, compact chord assumption and BEMT method) allowing for the initial loading noise analysis with highly reduced computational resources. The acquired results are fully compatible with the classical FW–H analysis in terms of the impact of the in-plane and out-of-plane forces on the generated noise. The FW–H code predictions of the acoustic pressure and its components are in satisfactory agreement with the reference and experimental data of Sargent and Schmitz.
Źródło:
Archives of Mechanics; 2022, 74, 2-3; 201-246
0373-2029
Pojawia się w:
Archives of Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analiza porównawcza sposobów wyznaczania obciążeń wiatrem na podstawie norm projektowych i analizy przepływu CFD
Comparative analysis of the methods of determining wind loads on the basis of design standards and CFD flow analysis
Autorzy:
Okoński, Robert
Ambroziak, Andrzej
Powiązania:
https://bibliotekanauki.pl/articles/2081880.pdf
Data publikacji:
2022
Wydawca:
Polski Związek Inżynierów i Techników Budownictwa
Tematy:
analiza CFD
numeryczna mechanika płynów
obciążenie wiatrem
PN-EN 1991-1-4
R-Wind Simulation
model budynku
nachylenie dachu
dach dwuspadowy
współczynnik parcia
CFD analysis
computational fluid dynamics
wind load
building model
roof slope
gable roof
pressure coefficient
Opis:
W pracy poruszono tematykę wykorzystania analizy przepływu CFD do wyznaczania obciążeń wiatru na konstrukcje. Przedstawiono analizę trzech modeli budynków o dachu dwuspadowym o różnych kątach nachylenia, dla których dokonano porównania wielkości współczynników parcia z wynikami dostępnymi w literaturze. Obliczenia analityczne wykonano zgodnie z normą z PN-EN 1991-1-4, natomiast obliczenia numeryczne wykonano w programie R-Wind Simulation. Całość wyników podsumowano, a wnioski sformułowano w odniesieniu do tematyki rozwiązania problemu szacowania wielkości obciążenia wiatru działającego na konstrukcję.
The paper addresses the use of CFD flow analysis to determine wind loads on structures. Three models of buildings with a gable roof with different angles of inclination were presented, for which the size of the pressure coefficients was compared with the results available in the literature. The analytical calculations were made in accordance with the PN-EN 1991-1-4 standard, while the numerical calculations were made in the R-Wind Simulation program. All the results were summarized and the conclusions were formulated in relation to the problem of solving the problem of estimating the size of the wind load acting on the structure.
Źródło:
Przegląd Budowlany; 2022, 93, 3-4; 46--57
0033-2038
Pojawia się w:
Przegląd Budowlany
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Assessment of polydisperse substrate flow in a fermentor for computational fluid dynamics modelling
Autorzy:
Wałowski, Grzegorz
Powiązania:
https://bibliotekanauki.pl/articles/2203566.pdf
Data publikacji:
2022
Wydawca:
Instytut Technologiczno-Przyrodniczy
Tematy:
adhesive bed
agricultural biogas
autocyclic flow
bioreactor
computational fluid dynamics
CFD
Klinkenberg phenomenon
Opis:
In this paper study results of selected production methods for agricultural biogas are shown and technical and technological aspects of these methods are described for monosubstrate bioreactors. Based on the available literature, modelling of mixing in bioreactors using computational fluid dynamics (CFD) was is demonstrated. As part of the research, the numerical simulation method was used with a tool that contains CFD codes. The model k-ε is used to simulate the mean flow characteristics under turbulent flow conditions. This is a two-equation model that gives a general description of turbulence. The work presents the results of numerical studies that make it possible to understand the characteristics of fluid flow in the adhesive bed used for the production of agricultural biogas. The tests showed that in the core of the adhesive bed there is a flow of 0.19 m∙s-1 , while in the outer part of the bed there is a flow in the range 0.01-0.02 m∙s-1. Taking into account the substrate inflow of 0.17 m∙s-1 (in the upper part of the fermentor), it was observed that the Klinkenberg effect for autocyclic movement (from bottom to top) takes place. The novelty in the article is the observation of the dominant flow in the core of the bed and the autocyclic flow in the opposite direction in the peripheral areas of the adhesive bed.
Źródło:
Journal of Water and Land Development; 2022, Special Issue; 1--7
1429-7426
2083-4535
Pojawia się w:
Journal of Water and Land Development
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
CFD analysis of nano-lubricated journal bearing considering variable viscosity and elastic deformation effects
Autorzy:
Kadhim, Zainab H.
Ahmed, Saba Y.
Abass, Basim A.
Powiązania:
https://bibliotekanauki.pl/articles/2096173.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Polskie Towarzystwo Diagnostyki Technicznej PAN
Tematy:
hydrodynamic journal bearings
computational fluid dynamics
thermohydrodynamic lubrication
nano-lubricant
elastic deformation
hydrodynamika
łożyska ślizgowe
numeryczna mechanika płynów
smarowanie hydrodynamiczne
odkształcenie sprężyste
Opis:
The main objective of the present work is to study the behavior of Nano-lubricated journal bearing considering elasticity and variable viscosity effects. A mathematical model for a journal bearing is employed using three-dimensional computational fluid dynamics. The study is implemented for a journal bearing with laminar flow and smooth surfaces lubricated with pure oil as well as lubricants containing different concentrations of Al2O3 Nano-particles. The dependence of the oil viscosity on the temperature is considered by using the modified Krieger Dougherty model. Pressure, temperature and elastic deformation in addition to the bearing load-carrying capacity of the bearing working under different eccentricity ratios (0.1-0.6) have been studied. The mathematical model is confirmed by comparing the results of the pressure and temperature distributions obtained in the current work with those obtained by Ferron et al.(1983) for a bearing lubricated with pure oil. Also, the pressure obtained for the Nano-lubricated bearing of the present work is validated with that obtained by Solighar (2015). The results are found in good agreement with a maximum deviation not exceeding 5%. The obtained results show that the oil film pressure increases by about 17.9% with a slight decrease in oil film temperature and friction coefficient.
Źródło:
Diagnostyka; 2022, 23, 1; 1--8
1641-6414
2449-5220
Pojawia się w:
Diagnostyka
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Computational fluid dynamics (CFD) aided design of a multi-rotor flying robot for locating sources of particulate matter pollution
Autorzy:
Suchanek, Grzegorz
Filipek, Roman
Powiązania:
https://bibliotekanauki.pl/articles/38435217.pdf
Data publikacji:
2022
Wydawca:
Polskie Towarzystwo Promocji Wiedzy
Tematy:
computational fluid dynamics
PM pollution
propeller aerodynamics
multi-rotor robot design
Opis:
The use of flying robots for various environmental protection issues is a very important and current research topic. Designing a dedicated multi-rotor flying robot is necessary for the efficient and automated localization of sources of air pollution, especially solid particles. In particular, one of the most important requirements that must be met by such a robot is its appropriate impact on the measurement process, i.e., increasing the sensitivity of sensors or reducing the interference. This is particularly difficult because its rotating rotors introduce significant disturbances to the surrounding fluid. In these studies, the design process is supported by the creation of a mathematical flow model and a series of analyzes to optimize the PM measurement system. The model is built using the finite-volume method in ANSYS Fluent software and steady-state RANS averaging. First, a flow field model with one propeller was modeled and its parameters identified by comparison with the results from the dedicated original dynamometer stand -- characteristics of the propeller performance. On the basis of the simulations and measurement of one rotor, subsequent systems of the highest practical importance are built. The effect of that design process was the preparation and testing of a functional robot prototype. The field parameter distributions resulting from the analyzes, in particular the turbulence intensity, allow one to propose a criterion on the basis of which both the best rotor configuration and localization of sensors are selected.
Źródło:
Applied Computer Science; 2022, 18, 3; 86-104
1895-3735
2353-6977
Pojawia się w:
Applied Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Computational prediction of the resistance of the the floatplane at various trim angles
Autorzy:
Sulisetyono, Aries
Fadhlurrohman, Ihsan
Ali, Baharudin
Zubaydi, Achmad
Powiązania:
https://bibliotekanauki.pl/articles/2086974.pdf
Data publikacji:
2022
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
resistance
floatplane
trim angle
computational fluid dynamics
Opis:
The prediction of the total resistance occurred during operation of a floatplane on the water surface is an important aspect in developing the floater as well as the engine power required. Theoretically, the trim angle of the floater may affect the total resistance. This paper intends to find the optimal trim angle for the take-off operation using the computational fluid dynamics (CFD) software. The floater set up under a fixed trim angle includes 2◦, 5◦ and 10◦ taken in simulation at five different speeds between 9.21 m/s and 15.87 m/s. In one case of 2◦ trim angle, the floater model test has been carried out in a tow tank laboratory to validate the accuracy of the numerical result. Comparison of both results has a good fit with an average error of 2.27%. In the final simulation results, the optimum trim angle is 5◦, which produces the total resistance less than 2◦ and 10◦ of the trim angle with average differences of 9.21% and 50.46% for all speeds, respectively.
Źródło:
Journal of Theoretical and Applied Mechanics; 2022, 60, 2; 267--278
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Enhancement of thermal efficiency of nanofluid flows in a flat solar collector using CFD
Autorzy:
Zarda, Falah
Hussein, Adnan Mohammed
Danook, Suad H.
Mohamad, Barhm
Powiązania:
https://bibliotekanauki.pl/articles/2146747.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Polskie Towarzystwo Diagnostyki Technicznej PAN
Tematy:
solar collector flat-plate
diamond/H2O nanofluids
thermal performance
computational fluid dynamics
płaski kolektor słoneczny
właściwości cieplne
numeryczna mechanika płynów
Opis:
Flat plate solar collector (FPSC) is popular for their low cost, simplicity, and ease of installation and operation. In this work, FPSC thermal performance was analyzed. It's compared to diamond/H2O nanofluids. The volume percentage and kind of nanoparticles are analyzed numerically that validation with experimental data available in the literature. The hot climate of Iraq is employed to approximate the model. The numerical study is performed by using ANSYS/FLUENT software to simulate the case study of problem. Due to less solar intensity after midday, temperatures reduction. The greatest collector thermal efficiency is 68.90% with 1% ND/water nanofluid, a 12.2% increase over pure water. The efficiency of 1% nanofluid is better than other concentrations because of a change in physical properties and an increase in thermal conductivity. Since the intensity of radiation affects the outlet temperature from the solar collector and there is a direct link between them, this increases the efficiency of the solar collector, especially around 12:30 pm at the optimum efficiency.
Źródło:
Diagnostyka; 2022, 23, 4; art. no. 2022411
1641-6414
2449-5220
Pojawia się w:
Diagnostyka
Dostawca treści:
Biblioteka Nauki
Artykuł

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