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Wyświetlanie 1-15 z 17
Tytuł:
Hall effects on MHD flow past an accelerated plate with heat transfer
Autorzy:
Sundarnath, J. K.
Muthucumarswamy, R.
Powiązania:
https://bibliotekanauki.pl/articles/264878.pdf
Data publikacji:
2015
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
Hall parameter
Hartmann number
heat transfer
Prandtl number
Opis:
Hall current and rotation on an MHD flow past an accelerated horizontal plate relative to a rotating fluid, In the presence of heat transfer has been analyzed. The effects of the Hall parameter, Hartmann number, rotation parameter (non-dimensional angular velocity), Grashof’s number and Prandtl number on axial and transverse velocity profiles are presented graphically. It is found that with the increase in the Hartmann number, the axial and transverse velocity components increase in a direction opposite to that of obtained by increasing the Hall parameter and rotation parameter. Also, when […], it is observed that the transverse velocity component vanishes and axial velocity attains a maximum value.
Źródło:
International Journal of Applied Mechanics and Engineering; 2015, 20, 1; 171-181
1734-4492
2353-9003
Pojawia się w:
International Journal of Applied Mechanics and Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The effects of inclination angle and Prandtl number on the mixed convection in the inclined lid driven cavity using lattice Boltzmann method
Analiza za pomocą siatki Boltzmanna wpływu kąta pochylenia oraz liczby Prandtla na mieszaną konwekcję w ukośnej szczelinie domkniętej ruchomą pokrywą
Autorzy:
Karimipour, A.
Nezhad, A. H.
D’Orazio, A.
Shirani, E.
Powiązania:
https://bibliotekanauki.pl/articles/280863.pdf
Data publikacji:
2013
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
LBM
inclination angle
Prandtl number
mixed convection
Opis:
The laminar mixed convection in a two-dimensional rectangular inclined cavity with moving top lid is investigated using the double population thermal lattice Boltzmann method (LBM) at different values of the Richardson number, inclination angle and the Prandtl number. In this problem, velocity components are changed by both buoyancy forces and the inclination angle of the cavity. Comparison of the present results with other available data show good agreement. As the results, the velocity and temperature profiles, the Nusselt number, streamlines and isotherms are presented and discussed. It is shown that the increase of Prandtl number enhances the heat transfer rate, especially at higher values of inclination angle and Richardson number. Moreover, the average Nusselt number at the upper limit of the considered range of the Richardson and Prandtl numbers variability increases by a factor of 9.
W pracy zajęto się problemem mieszanej konwekcji laminarnej w dwuwymiarowej, prostokątnej i ukośnie usytuowanej szczelinie domkniętej od góry ruchomą pokrywą. W badaniach zastosowano metodę siatki termicznej Boltzmanna (LBM) podwójnej populacji, uwzględniając rożne wartości liczby Richardsona, kąta pochylenia szczeliny oraz liczby Prandtla. W rozważanym zagadnieniu, składowe prędkości zostały poddane zmianom indukowanym siłami wyporu oraz kątem pochylenia szczeliny. Porównanie otrzymanych wynikow analizy z dostępnymi w literaturze danymi wykazało dobrą zgodność. Rezultatem badań w pracy są także profile rozkładu prędkości i temperatury, liczba Nusselta, linie prądu oraz izotermy, które szczegółowo przedyskutowano. Pokazano, że wzrost liczby Prandtla zwiększa transfer ciepła, zwłaszcza dla wyższych wartości kąta pochylenia szczelin i liczby Richardsona. Co więcej, średnia liczba Nusselta przy górnych wartościach przyjętego zakresu zmienności liczb Richardsona i Prandtla wzrasta 9-krotnie.
Źródło:
Journal of Theoretical and Applied Mechanics; 2013, 51, 2; 447-462
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Anisotropic turbulent viscosity and large-scale motive force in thermally driven turbulence at low Prandtl number
Autorzy:
Mizerski, K. A.
Powiązania:
https://bibliotekanauki.pl/articles/38695701.pdf
Data publikacji:
2022
Wydawca:
Instytut Podstawowych Problemów Techniki PAN
Tematy:
thermal convection
heat transport
Rayleigh number
Prandtl number
random heat source
Opis:
The fully developed turbulent Boussinesq convection is known to form large-scale rolls, often termed the ‘large-scale circulation’ (LSC). It is an interesting question how such a large-scale flow is created, in particular in systems when the energy input occurs at small scales, when inverse cascade is required in order to transfer energy into the large-scale modes. Here, the small-scale driving is introduced through stochastic, randomly distributed heat source (say radiational). The mean flow equations are derived by means of simplified renormalization group technique, which can be termed a ‘weakly nonlinear renormalization procedure’ based on consideration of only the leading order terms at each step of the recursion procedure, as full renormalization in the studied anisotropic case turns out unattainable. The effective, anisotropic viscosity is obtained and it is shown that the inverse energy cascade occurs via an effective ‘motive force’ which takes the form of transient negative, vertical diffusion.
Źródło:
Archives of Mechanics; 2022, 74, 5; 409-436
0373-2029
Pojawia się w:
Archives of Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Flow of viscous incompressible MHD fluid over a suddenly accelerated plate with variable electroconductivity and chemical reaction provoked by radiation
Autorzy:
Ngiangia, Alalibo T.
Powiązania:
https://bibliotekanauki.pl/articles/1191366.pdf
Data publikacji:
2016
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
Chemical reaction
Electrconductivity
Grashof number
MHD
Prandtl number
Radiation
Reynold’s Number
Opis:
A study of a suddenly accelerated plate with variable approximated electronegativity with MHD fluid provoked by chemical reaction and radiation is made. The governing hydrodynamical equations of the physical problem was formulated and its solution and analysis showed that increase in electroconductivity, prandtl number, Reynold’s number, Grashof number, chemical reaction and radiation all result to a corresponding increase in the velocity profile of the fluid while magnetic field increase results to a decrease in the velocity profile of the fluid. The shear stress at the wall of the plate was also determined.
Źródło:
World Scientific News; 2016, 34; 135-145
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of Variable Electroconductivity and Radiation on MHD Couette Flow
Autorzy:
Ngiangia, Alalibo T.
Okechukwu, Amadi
Powiązania:
https://bibliotekanauki.pl/articles/1192671.pdf
Data publikacji:
2016
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
MHD
Electrconductivity
Prandtl number
Grashof number
Reynolds Number
Radiation
Couette flow
Opis:
A study of Couette flow in cylindrical coordinate under the influence electroconductivity and magnetic field was carried out. Approximate solution of the governing equations and its analysis show decrease in temperature as a result of increase in radiation and Prandtl number. The study also reveals that increase in grashof number, Reynolds number, Prandtl number and electroconductivity result in an increase in velocity distribution while magnetic field increase, lead to a decrease in velocity. The shear stresses of the outer and inner cylinders at the wall of the plates and the heat flux is also determined.
Źródło:
World Scientific News; 2016, 47, 2; 241-253
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Finite Different Analysis of Free Convection Flow and Heat Transfer of Casson Nanofluid over a Vertical Plate under the Influence of Thermal Radiation
Autorzy:
Sobamowo, M. G.
Okolie, A. C.
Powiązania:
https://bibliotekanauki.pl/articles/1193438.pdf
Data publikacji:
2021
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
Casson fluid
Free convection
Nanoparticle
Numerical solutions
Prandtl number
Thermal radiation
Opis:
In this paper, a numerical study on free convection flow and heat transfer of Casson nanofluids over a vertical plate under the influence of thermal radiation is carried out. The governing systems of coupled nonlinear partial differential equations of the flow and heat transfer processes are converted to a system of coupled nonlinear ordinary differential equations through suitable similarity variables. The obtained ordinary differential equations are solved using finite difference method. The results of the numerical solutions are compared with the results of past works as presented in literature and good agreement was established. Also, the effects of thermal radiation; Prandtl number, nanoparticles volume-fraction, shape and type on the flow and heat transfer behaviour of various nanofluids over the flat plate are investigated. The results show that the magnitude of velocity near the plate for the Casson nanofluid parameter decreases for increasing value of the Casson parameter, while temperature increases for increase in Casson fluid parameter. Also, the thermal radiation and volume-fraction of the nanoparticles in the base fluid increase, the velocity, temperature, viscous and thermal boundary layers of the nanofluid increase. However, the velocity of the nanofluid decreases as the Prandtl number increases while the temperature of the nanofluid increases as the Prandtl number increases. The velocity of the nanofluid decreases as the volume-fraction or concentration of the nanoparticle in the base fluid increases. The study can benefit the design engineers enhancing their understanding of the phenomenon for various industrial and engineering applications.
Źródło:
World Scientific News; 2021, 157; 38-66
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Vertical heat transport at infinite Prandtl number for micropolar fluid
Autorzy:
Caggio, M.
Kalita, P.
Łukaszewicz, G.
Mizerski, K. A.
Powiązania:
https://bibliotekanauki.pl/articles/38611128.pdf
Data publikacji:
2020
Wydawca:
Instytut Podstawowych Problemów Techniki PAN
Tematy:
micropolar fluid
Rayleigh–Benard convection
heat transport
Rayleigh number
Prandtl number
Nusselt number
Opis:
We investigate the upper bound on the vertical heat transport in the fully 3D Rayleigh–Bénard convection problem at the infinite Prandtl number for a micropolar fluid. We obtain a bound, given by the cube root of the Rayleigh number, with a logarithmic correction. The derived bound is compared with the optimal known one for the Newtonian fluid. It follows that the (optimal) upper bound for the micropolar fluid is less than the corresponding bound for the Newtonian fluid at the same Rayleigh number. Moreover, strong microrotational diffusion effects can entirely suppress the heat transfer. In the Newtonian limit our purely analytical findings fully agree with estimates and scaling laws obtained from previous theories significantly relying on phenomenology.
Źródło:
Archives of Mechanics; 2020, 72, 6; 525-553
0373-2029
Pojawia się w:
Archives of Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A turbulent heat flux two-equation $Θ^2 - ε_Θ$ closure based on the V2F turbulence model
Autorzy:
Karcz, M.
Badur, J.
Powiązania:
https://bibliotekanauki.pl/articles/2028986.pdf
Data publikacji:
2003
Wydawca:
Politechnika Gdańska
Tematy:
turbulent heat transfer
turbulent Prandtl number
Durbin's model of turbulence
low Reynolds number models
Opis:
The paper deals with the proposition of a two-equation turbulent heat flux closure without any damping function. The model has been based on Durbin's V2F dynamic turbulence closure and the Deng-Wu-Xi thermal turbulence model. Both models have been implemented into the FLUENT code by a User Defined Function. Results of numerical computation have been compared with experimental data for developing a thermal field in a pipe by Nagano and DNS heat transfer prediction for a two-dimensional channel flow by Kasagi.
Źródło:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk; 2003, 7, 3; 375-387
1428-6394
Pojawia się w:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On the onset of thermal convection in a layer of Oldroydian visco-elastic fluid saturated by Brinkman–Darcy porous medium
Autorzy:
Chand, R.
Powiązania:
https://bibliotekanauki.pl/articles/178803.pdf
Data publikacji:
2015
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
thermal instability
Oldroydian viscoelastic fluid
Brinkman–Darcy number
Prandtl–Darcy number
Opis:
Thermal instability in a horizontal layer of Oldroydian visco-elastic fluid in a porous medium is investigated. For porous medium the Brinkman–Darcy model is considered. A linear stability analysis based upon perturbation method and normal mode technique is used to find solution of the fluid layer confined between two free-free boundaries. The onset criterion for stationary and oscillatory convection is derived analytically. The influence of the Brinkman–Darcy, Prandtl–Darcy number, stress relaxation parameter on the stationary and oscillatory convection is studied both analytically and graphically. The sufficient condition for the validity of PES has also been derived.
Źródło:
Studia Geotechnica et Mechanica; 2015, 37, 4; 3-10
0137-6365
2083-831X
Pojawia się w:
Studia Geotechnica et Mechanica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Heat transfer study from square cylinder immersed in water-based nanofluid: Effect of orientation
Autorzy:
Kaur, Jaspinder
Ratar, Jatinder Kumar
Tiwari, Anurag Kumar
Powiązania:
https://bibliotekanauki.pl/articles/2173435.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
inclined square cylinder
nanofluids
Reynolds number
Prandtl number
steady flow
regime
nanopłyn
liczba Reynoldsa
liczba Prandtla
przepływ stały
Opis:
Heat transfer study from the heated square cylinder at a different orientation angle to the stream of nanofluids has been investigated numerically. CuO-based nanofluids were used to elucidate the significant effect of parameters: Reynolds number (1–40), nanoparticle volume fraction (0.00–0.05), the diameter of the NPs (30–100 mn) and the orientation of square cylinder (0–90). The numerical results were expressed in terms of isotherm contours and average Nusselt number to explain the effect of relevant parameters. Over the range of conditions, the separation of the boundary layers of nanofluids increased with the size of the NPs as compared to pure water. NPs volume fraction and its size had a significant effect on heat transfer rate. The square cylinder of orientation angle (45) gained a more efficient heat transfer cylinder than other orientation angles. Finally, the correlations were developed for the average Nusselt number in terms of the relevant parameters for 45 orientation of the cylinder for new applications.
Źródło:
Chemical and Process Engineering; 2022, 43, 2; 243--250
0208-6425
2300-1925
Pojawia się w:
Chemical and Process Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A numerical study of coupled non-linear equations of thermo-viscous fluid flow in cylindrical geometry
Autorzy:
Pothanna, N.
Aparna, P.
Gorla, R. S. R.
Powiązania:
https://bibliotekanauki.pl/articles/265510.pdf
Data publikacji:
2017
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
Reiner Rivlin Cross viscosity
thermal conductivity
thermo-stress viscosity
Prandtl number
lepkość
przenoszenie ciepła
liczba Prandtla
Opis:
In this paper we present numerical solutions to coupled non-linear governing equations of thermo-viscous fluid flow in cylindrical geometry using MATHEMATICA software solver. The numerical results are presented in terms of velocity, temperature and pressure distribution for various values of the material parameters such as the thermo-mechanical stress coefficient, thermal conductivity coefficient, Reiner Rivlin cross viscosity coefficient and the Prandtl number in the form of tables and graphs. Also, the solutions to governing equations for slow steady motion of a fluid have been obtained numerically and compared with the existing analytical results and are found to be in excellent agreement. The results of the present study will hopefully enable a better understanding applications of the flow under consideration.
Źródło:
International Journal of Applied Mechanics and Engineering; 2017, 22, 4; 965-979
1734-4492
2353-9003
Pojawia się w:
International Journal of Applied Mechanics and Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Enhancement of heat transfer in helical coil heat exchangers using nano-fluids
Autorzy:
Parveez, Malik
Hanief, Mohammad
Powiązania:
https://bibliotekanauki.pl/articles/2173429.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
nano-fluids
heat transfer
Nusselt number
Prandtl number
volume fraction
nanopłyny
przenoszenie ciepła
liczba Nusselta
liczba Prandtla
ułamek objętościowy
Opis:
Investigation for heat transfer behaviour of Al2O3 and CuO nano-fluid in helical coil heat exchangers was carried out in this study. The thermo-physical properties of the fluids have temperature dependent nature. The main emphasis was to depict the influence of nano-particle concentration by volume on the characteristics of temperature, rate of heat transfer and heat transfer coefficients (convective). In order to enhance efficiency, density and thermal conductivity are considered to be the most important variables. In comparison to water and for equal flow rate, the rate of heat transfer of nano-fluid increases conspicuously. Efficiency of the helical coil heat exchanger increased by 38.80%.
Źródło:
Chemical and Process Engineering; 2022, 43, 2; 279--283
0208-6425
2300-1925
Pojawia się w:
Chemical and Process Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Unsteady MHD natural convective boundary layer flow and heat transfer over a truncated cone in the presence of pressure work
Autorzy:
Ajay, C. K.
Srinivasa, A. H.
Powiązania:
https://bibliotekanauki.pl/articles/122607.pdf
Data publikacji:
2020
Wydawca:
Politechnika Częstochowska. Wydawnictwo Politechniki Częstochowskiej
Tematy:
convection
pressure work
truncated cone
MHD
Prandtl number
przepływ konwekcyjny
konwekcja
stożek ścięty
liczba Prandtla
wymiana ciepła
Opis:
The aim of the present paper is to analyse the effect of MHD on unsteady natural convection boundary layer flow and heat transfer over a truncated cone in the presence of pressure work. Suitable transformation is utilized to form a system of coupled non-linear partial differential equations for governing both the flow and heat transfer. These equations have been solved numerically by utilizing an implicit finite difference scheme along with quasilinearization method. Here, the computed numerical results are displayed graphically in terms of the local Nusselt number, skin friction, temperature distribution, and velocity distribution for various values of the magnetic and pressure work parameters along with the fixed Prandtl number
Źródło:
Journal of Applied Mathematics and Computational Mechanics; 2020, 19, 1; 1-16
2299-9965
Pojawia się w:
Journal of Applied Mathematics and Computational Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Unsteady MHD natural convective boundary layer flow and heat transfer over a truncated cone in the presence of pressure work
Autorzy:
Ajay, C. K.
Srinivasa, A. H.
Powiązania:
https://bibliotekanauki.pl/articles/1839804.pdf
Data publikacji:
2020
Wydawca:
Politechnika Częstochowska. Wydawnictwo Politechniki Częstochowskiej
Tematy:
convection
pressure work
truncated cone
MHD
Prandtl number
przepływ konwekcyjny
konwekcja
stożek ścięty
liczba Prandtla
wymiana ciepła
Opis:
The aim of the present paper is to analyse the effect of MHD on unsteady natural convection boundary layer flow and heat transfer over a truncated cone in the presence of pressure work. Suitable transformation is utilized to form a system of coupled non-linear partial differential equations for governing both the flow and heat transfer. These equations have been solved numerically by utilizing an implicit finite difference scheme along with quasilinearization method. Here, the computed numerical results are displayed graphically in terms of the local Nusselt number, skin friction, temperature distribution, and velocity distribution for various values of the magnetic and pressure work parameters along with the fixed Prandtl number
Źródło:
Journal of Applied Mathematics and Computational Mechanics; 2020, 19, 1; 5-16
2299-9965
Pojawia się w:
Journal of Applied Mathematics and Computational Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Combined effects of Soret and Dufour on MHD flow of a power-law fluid over flat plate in slip flow rigime
Autorzy:
Saritha, K.
Rajasekhar, M. N.
Reddy, B. S.
Powiązania:
https://bibliotekanauki.pl/articles/265391.pdf
Data publikacji:
2018
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
liczba Prandtla
warunki granicy poślizgu
zjawisko Dufoura
power-law fluid
Soret and Dufour number
slip boundary conditions
finite difference method
Prandtl number
Opis:
A numerical model is developed to study the Soret and Dufour effects on MHD boundary layer flow of a power-law fluid over a flat plate with velocity, thermal and solutal slip boundary conditions. The governing equations for momentum, energy and mass are transformed to a set of non-linear coupled ordinary differential equations by using similarity transformations. These non-linear ordinary differential equations are first linearized using a quasi-linearization technique and then solved numerically based on the implicit finite difference scheme over the entire range of physical parameters with appropriate boundary conditions. The influence of various governing parameters along with velocity, thermal and mass slip parameters on velocity, temperature and concentration fields are examined graphically. Also, the effects of slip parameters, the Soret and Dufour number on the skin friction, Nusselt number and Sherwood number are studied. Results show that the increase in the Soret number leads to a decrease in the temperature distribution and to an increase in concentration fields.
Źródło:
International Journal of Applied Mechanics and Engineering; 2018, 23, 3; 689-705
1734-4492
2353-9003
Pojawia się w:
International Journal of Applied Mechanics and Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-15 z 17

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