A numerical investigation of natural convection heat transfer stability in cylindrical annular with discrete isoflux heat source of different lengths is carried out. The adiabatic unheated portions ...and the discrete heat source are mounted at the inner wall. The top and bottom walls are adiabatic, while the outer wall is maintained at a lower temperature. The governing equations are numerically solved using a finite volume method. SIMPLER algorithm is used for the pressure–velocity coupling in the momentum equation. The numerical results for various governing parameters of the problem are discussed in terms of streamlines, isotherms and Nusselt number in the annulus. The results show that the increase of heat source length ratio decreases the critical Rayleigh number. We can control the flow stability and heat transfer rate in varying of the length of heat source.
Many engineers and scientists are working on various studies such as cosmetics, medicines, chemicals, oil, gas, food and many others due to the numerous applications of non-Newtonian fluids in ...technological development and improvement. It is difficult to deal with non-Newtonian fluids compared to Newtonian fluids. Due to the vast applications, a numerical investigation of mixed and convective Casson liquid flow through a duct within a permeable medium under the Lorentz force effect is carried out. The problem is modelled mathematically by employing the mass, momentum, heat energy and conservation laws. The partial differential equations (PDEs) are changed into nonlinear ordinary differential equations (ODEs). These ODEs are numerically computed using the shooting technique and then validated through the Runge–Kutta–Fehlberg method. The influence due to Reynolds, Prandtl and Schmidt numbers and Casson, magnetic, porosity, thermal buoyancy and reaction rate parameters are illustrated graphically and in tabular representation to make the analysis more interesting. This study revealed that the transfer rates of heat energy and mass at the lower wall enhanced with the augmenting values of the thermal buoyancy parameter. There is a linear relationship between the velocity of the Casson parameter and Reynolds numbers. Moreover, velocity enhances with the higher magnetic and porosity parameters and diminishes with higher values of thermal buoyancy, Reynolds number and porosity parameters.
The impact of the flow of nanoparticles in nanofluids (NFs) across a vertical area is considerable, and its request in engineering, medical sciences, pharmaceutical, and food industries is vast and ...widely published. Nevertheless, the comparative analysis of alumina (Al
2
O
3
) nanoparticles through cupric (CuO) nanoparticles over a rapid progressive Riga plate remains unidentified. Hence, this report scrutinizes water-based Al
2
O
3
and CuO nanoparticles via an exponentially accelerated Riga plate. NFs containing aluminium oxide and copper (II) oxide nanoparticles are considered. The Laplace transform technique is utilized to solve the PDEs guiding the flow. The range of the nanoparticle volume fraction is 1–4%, the buoyancy forces convection ranging from 5 to 20, and the modified Hartmann number ranging from 1 to 6. The impact of a variety of factors on Nusselt number, skin friction coefficient, temperature, and velocity profiles is examined and reported in tabular and graphical form. The upsurge of radiative impact and modified Hartmann number improves CuO NF compared to Al
2
O
3
NF due to Lorentz force and since cupric is a better heat conductor. At the same time, heat absorption and reactive species favour a slight decline in Al
2
O
3
NF than CuO NF in the thermal and velocity fields. The higher density of cupric NF is improved by rising nanoparticle volume fraction over Al
2
O
3
NF through a decline in velocity distribution.
In this paper, we have investigated the two-dimensional magnetohydrodynamic steady boundary layer flow of a viscous magnetomicropolar liquid via an extending area. The impact of heat sink/source and ...chemical reaction is considered. The governing equations are modeled in Cartesian coordinate system. Using the suitable similarity transformations, the partial differential equations system is changed into the nonlinear ordinary differential equations system. The resulting system of equations is solved via mathematical renowned software Mathematica. The impact of diverse parameters through microrotation, concentration, temperature and velocity is examined via graphs. The present study reveals that the velocity is rising function of Soret number, Richardson number and Grashof number. It is mentioned that the greater velocity is located in the case of Newtonian liquid in contrast with the micropolar liquid. In the absence of chemical reaction parameter, the velocity is more as compared with higher chemical reaction parameter. Radiation, Hartmann and chemical reaction parameters augment the temperature. Concentration is a reducing function of radiation, Hartmann and chemical reaction parameters.
MRI image segmentation is very challenging area in medical image processing. It is implemented with the low contract of MRI scan. In terms of certain input features or expert information, the major ...objective of medical image segmentation is to isolate and describe anatomical constitutions. In MRI image segmentation, brain tumor segmentation is more difficult because of its complex structure. The Otsu’s thresholding method is well-known method in image segmentation. In this paper, choosing the classes or bins of Otsu’s thresholding are analyzed on MRI image brain tumor segmentation. As a preprocessing, the 2D MRI images are convert the grayscale image and resized to the same size. And then, median filter is utilized to eliminate the noise from MRI image. In MRI image segmentation, the varieties of classes or bins of Otsu’s thresholding are utilized to segment the brain tumor from MRI images. Then, the morphological operation is used to achieve the accurate tumor regions. All of the experiments are tested on 2015 BRATS dataset. As segmentation quality validation metric, Jaccard similarity index, true positive rate (Sensitivity), true negative rate (Specificity) and accuracy are used to validate the segmented results and their ground truth. According to the results, level 4 or class 4 got 68.7955% in true positive and 95.5593% in accuracy. Class 4 is the best or suitable for MRI image segmentation according to experiments.
Variable properties play a prominent role in analyzing the blood flow in narrow arteries. Specifically, considering the variation of thermal conductivity and viscosity helps in the understanding of ...the rheological behavior of blood and other biological fluids, such as urine, spermatozoa, and eye drops. Inspired by these applications, the current study incorporates the impact of variable thermal conductivity and viscosity for modeling the peristaltic flow of a Ree–Eyring liquid through a uniform compliant channel. The governing equations are nondimensionalized with the assistance of similarity transformations. The long‐wavelength and small Reynolds wide variety approximation are utilized for solving the governing differential equations. Furthermore, the series solution method (perturbation technique) is utilized for solving the nonlinear temperature equation. The obtained results show that the velocity is greater in the case of the Newtonian liquid than that of the non‐Newtonian liquid.
In this work, natural convection of Cu—water nanofluid in a vertical cylindrical annulus enclosure with two discrete heat sources of different lengths is numerically investigated using the finite ...volume method with SIMPLER algorithm. The adiabatic unheated portions and the discrete heat sources are mounted at the inner wall. The top and bottom walls are thermally isolated, while the outer wall is maintained at a lower temperature. The effects of nanofluid solid volume fraction on hydrodynamic and thermal characteristics such as average and local Nusselt numbers, streamlines, and isotherm patterns for the Rayleigh number ranges from 10
3
to 10
6
and solid volume fraction ranges from 0 to 0.1 are presented. The heat transfer and temperature of heaters depend on the Rayleigh number, the solid volume fraction of nanoparticles, and the length of heaters.
A numerical study of oscillatory magnetohydrodynamic (MHD) natural convection of liquid metal between vertical coaxial cylinders is carried out. The motivation of this study is to determine the value ...of the critical Rayleigh number, Racr for two orientations of the magnetic field and different values of the Hartmann number (Harand Haz) and aspect ratios A. The inner and outer cylinders are maintained at uniform temperatures, while the horizontal top and bottom walls are thermally insulated. The governing equations are numerically solved using a finite volume method. Comparisons with previous results were performed and found to be in excellent agreement. The numerical results for various governing parameters of the problem are discussed in terms of streamlines, isotherms and Nusselt number in the annuli. The time evolution of velocity, temperature, streamlines and Nusselt number with Racr, Har, Haz, and A is quite interesting. We can control the flow stability and heat transfer rate in varying the aspect ratio, intensity and direction of the magnetic field.
Solving nonlinear differential equation of a circular sector oscillator is of a scientific importance. Thus, to solve such equations, a single- step implicit block method involving one hybrid point ...with the introduction of a third derivative is proposed. To derive this method, the approximate basis solution is interpolated at {
x
n
,
x
n
+ 3/5
} while its second and third derivatives are collocated at all points {
x
n
,
x
n
+ 3/5
,
x
n
+ 1
}on the integrated interval of approximation. Numerical results are presented in the form of table and graphs for the variation of different physical parameters. The study reveals that the proposed hybrid block method is zero stable, which proves that it is convergent beside a significant interval of absolute stability, thus making it suitable for solving stiff ODEs.
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