G-Jitter effect on heat and mass transfer of three-dimensional stagnation point nanofluid flow

The study of fluid motion in fluid mechanics is useful in many engineering applications. Fundamental studies based on physics law on fluid motion could be done by mathematical formulation. Effects based on thermal energy such as heat source and heat absorber with its transferring mode can also be formulated into a mathematical system. Due to this reason, a boundary layer nanofluid flow near a stagnation point region of a three-dimensional body is studied in this thesis. Here, nanofluid containing copper nanoparticles and hybrid nanofluid containing copper and alumina nanoparticles with water as a base fluid are considered. In addition, a microgravitational field environment known as g-jitter is also considered. The main purpose of this study is to investigate theoretically the effect of thermal radiation and heat generation on fluid characteristics, heat transfer behaviour, and concentration distribution of the fluid flow system. In this study, the mathematical models that govern the fluid flow consist of continuity, momentum, energy, and concentration equations. These nonlinear partial differential equations are initially reduced into a dimensionless system of equations using the similarity transformation technique. The resulting dimensionless governing systems are then solved numerically using the Keller-box method. The numerical values of the skin friction coefficients, Nusselt number, and Sherwood number as well as the velocity, temperature, and concentration profiles are obtained for various values of the curvature ratio, amplitude of modulation, frequency of oscillation, nanoparticle volume fraction, heat generation parameter and thermal radiation parameter. The results from the analysis in relation to the studied physical parameters are graphically displayed and validated by comparing them to those of previous studies. The current study shows that the curvature parameter had a significant effect on the skin friction coefficient where planar and axisymmetric stagnation point flow occurred in a specified range of this parameter. On the other hand, increasing the modulation's amplitude causes all the physical quantities to fluctuate. It is observed that, when a higher frequency of oscillation is induced, the physical quantities are seen to be reduced. The addition of a small amount of copper nanoparticle in the fluid results in enhancement of conductivity of the thermal, as demonstrated by the Nusselt number. However, a contradictory behaviour was noticed on Sherwood number as copper nanoparticle was considered in the fluid problem. The internal heat generation has caused the temperature profile to increase, while the heat flux to decrease. Also, thermal radiation is found to improve the rate of heat transfer. Moreover, the addition of other nanoparticles which are alumina, further increased the thermal characteristic of the fluid system

Parameters estimation for a mechanistic model of high dose irradiation damages using Nelder-Mead simplex method and genetic algorithm

Radiation therapy is one of the cancer cells treatments that use high-energy radiation to shrink tumors and kill cancer cells. Radiation therapy kills cancer cells by damaging their DNA directly or creates charged particles within the cells that can in turn damage the DNA. As a side effect of the treatment, the radiation therapy can also damage the normal cell that located at parts of our body. The main goals of radiation therapy are to maximise the damaging of tumors cell and minimise the damage of normal tissue cell. Hence, in this study, we adopt an existing model of high dose irradiation damage. The purpose of this study is to estimate the six parameters of the model which are involved. Two optimisation algorithms is used in order to estimate the parameters, there are Nelder-Mead simplex method and Genetic Algorithm. Both methods have to achieve the objective function which are to minimise the sum of square error (SSE) between the experimental data and simulation data. The performance of both algorithms are compared based on the computational time, number of iteration and value of sum of square error. The optimisation process is carried out using MATLAB programming built-in functions. The parameters estimation results shown that Nelder- Mead simplex method is more superior than Genetic Algorithm for this problem

Parameter estimation for a mechanistic model of high dose irradiation damage using Nelder-Mead simplex method and genetic algorithm

Radiation therapy is one of the cancer cells treatments that use high-energy radiation to shrink tumors and kill cancer cells. Radiation therapy kills cancer cells by damaging their DNA directly or creates charged particles within the cells that can in turn damage the DNA. As a side effect of the treatment, the radiation therapy can also damage the normal cell that located at parts of our body. The main goals of radiation therapy are to maximize the damaging of tumors cell and minimize the damage of normal tissue cell. Hence, in this study, we adopt an existing model of high dose irradiation damage. The purpose of this study is to estimate the six parameters of the model which are involved. Two optimization algorithms are used in order to estimate the parameters: Nelder-Mead (NM) simplex method and Genetic Algorithm (GA). Both methods have to achieve the objective function which is to minimize the sum of square error (SSE) between the experimental data and the simulation data. The performances of both algorithms are compared based on the computational time, number of iteration and value of sum of square error. The optimization process is carried out using MATLAB programming built-in functions. The parameters estimation results shown that Nelder-Mead simplex method is more superior compare to Genetic Algorithm for this problem

Mathematical modeling for contour identification based on medicinal leaves and GIS images

In this paper, the identification of contour medicinal leaves and GIS images has been determined. The purposes of the Geodesic Active Contour-Additive Operating Splitting (GAC-AOS) modelling are to identify an unknown type of medicinal leaves and edge detection of our images. Besides, three iterative methods such as SOR, RBGS and Jacobi method are used to solve the linear system of equations. In the implementation of the GAC-the AOS model, the experimental result demonstrates that the SOR method gives the best performance compared to the other two methods. The computation platform is based on Intel® CoreTM Duo Processor Architecture with MATLAB version R2011a. The performance analysis is based on the iteration numbers, execution time, accuracy and RMSE

Quadratic convective nanofluid flow at a three-dimensional stagnation point with the g-jitter effect

The nonlinear density variation with temperature happens in many thermal applications like solar collectors, energy production, heat exchangers, and combustions, and it gives a significant impact on heat transfer and fluid flows. Thus, a nonlinear convective of an unsteady stagnation point flow under the influence of gravity modulation in the presence of water-based nanoparticles alumina (Al2O3) is studied here. Suitable variables are utilized to reduce the highly coupled nonlinear governing equations into a system of dimensionless simple partial differential equations. The Keller-box method is then applied to solve the consequent governing equations. Velocity and temperature profiles for various values of pertinent parameters are displayed graphically and discussed. The results indicate that the quadratic convection has enhanced the fluid flow and heat transport. Furthermore, the nonlinear convection parameter and the nanoparticles volume fractions have delivered a positive effect on the skin friction and the rate of heat transfer

Numerical solutions on Reiner-Philippoff (RP) fluid model with velocity and thermal slip boundary condition

Non-Newtonian fluid model was created against the Newton’s Law of viscosity where the viscosity is no more constant and dependent on the shear rate. The existing such fluid can be found in many industrial claims especially in food manufacturing, lubrication, biomedical flows and oil and gas. Besides, the used of non Newtonian fluid occurs in mining industry where the slurries and muds are often handled. There are many models on non-Newtonian fluid available in literature where some of them capture the specific properties. The Reiner–Philippoff (RP) fluid model is considered in this endeavour due to the capabilities of the model which can be acted in three different family of fluid which are viscous, shear thickening and the shear-thinning. Mathematical model is constructed using continuity, momentum and energy equations where in form of partial differential equations (PDEs). The complexity of the proposed model is abridged by deduced the equations into ordinary differential equations (ODEs) by adopting similarity variablesbefore the computation is done by bvp4c function drive in MATLABsoftware. To ratify the validity of the proposed model as well as numerical outputs, the comparative study is performed and it found to be in very strong agreement under limiting case where the present model is condensed to be identical with the reported model previously. The consequences of pertinent parameters on fluid’s characteristics are analyzed in details through the plotted graphic visuals and tabular form

Numerical Solutions on Reiner–Philippoff (RP) Fluid Model with Velocity and Thermal Slip Boundary Condition

Non-Newtonian fluid model was created against the Newton’s Law of viscosity where the viscosity is no more constant and dependent on the shear rate. The existing such fluid can be found in many industrial claims especially in food manufacturing, lubrication, biomedical flows and oil and gas. Besides, the used of non-Newtonian fluid occurs in mining industry where the slurries and muds are often handled. There are many models on non-Newtonian fluid available in literature where some of them capture the specific properties. The Reiner–Philippoff (RP) fluid model is considered in this endeavour due to the capabilities of the model which can be acted in three different family of fluid which are viscous, shear thickening and the shear-thinning. Mathematical model is constructed using continuity, momentum and energy equations where in form of partial differential equations (PDEs). The complexity of the proposed model is abridged by deduced the equations into ordinary differential equations (ODEs) by adopting similarity variables before the computation is done by bvp4c function drive in MATLAB software. To ratify the validity of the proposed model as well as numerical outputs, the comparative study is performed and it found to be in very strong agreement under limiting case where the present model is condensed to be identical with the reported model previously. The consequences of pertinent parameters on fluid’s characteristics are analyzed in details through the plotted graphic visuals and tabular form. © 2022, Penerbit Akademia Baru. All rights reserved

Flow and heat transfer analysis on reiner-philippoff fluid flow over a stretching sheet in the presence of first and second order velocity slip and temperature jump effects

Most of the fluid used in industrial application (i.e. Oils and gas industry, food manufacturing, lubrication and biomedical) do not conform to the Newtonian postulate. In contrast to the Newtonian fluid, the viscosity of the fluid can change when under force to either more liquid or more solid and dependent on shear rate history. This behaviour of fluids is commonly known as non-Newtonian fluid. The non-Newtonian fluid is so widespread in nature and technology resulting in very high interest of investigating among scientist. The Reiner-Philippoff fluid is one of the types of non-Newtonian fluid models that exhibiting the dilatant, pseudoplastic and Newtonian behaviors. Hence, this study is devoted to analyze the flow and heat transfer of Reiner-Philippoff fluid with the presence of first and second order velocity slip together with the temperature jump effects over a stretching sheet. Partial differential equations of continuity, momentum and energy equations were transformed into the similarity equations. The obtained equations were then solved via bvp4c function in MATLAB software. For the validation purpose, the present model and its numerical solution were compared with previous established solutions under limiting case where the present model is condensed to be identical with the reported model and turn to be in very strong agreement. The consequences of pertinent parameters on fluid’s characteristics are analyzed in details through the plotted graphic visuals and tabular form

Flow Analysis on Boundary Layer of Porous Horizontal Circular Cylinder Filled by Viscoelastic-Micropolar Fluid

This study emphasis on the analysis of boundary layer flow of viscoelastic fluid with microrotation moving over a porous horizontal circular cylinder. The model of the problem is based on Navier Stokes equations which involved continuity, momentum and micro inertia equations. The mentioned equations are first undergo Boussinesq and boundary layer approximation before transforming to non-dimensional form which in partial differential equations system. Since the boundary layer equations of viscoelastic fluid are an order higher than Newtonian (viscous) fluid, the adherence boundary conditions are insufficient to govern the solutions entirely. Hence, the augmentation of an extra boundary conditions is necessary to perform the computation. The computation is done by adopting the established procedures called Keller box method. The results are computed for velocity and microrotation distribution as well as skin friction coefficient. It is worth to mentioned at the special case, the present model can be deduced to the established model where the porosity, microinertia and magnetic term excluded. The output computed will be served as a reference to study the complex fluid especially when the fluid exhibit both viscous and elastic characteristics with microrotation effect

G-Jitter free convection flow of nanofluid in the three-dimensional stagnation point region

The free convection boundary layer flow near a three-dimensional stagnation point region is studied numerically with the implementation of nanofluid. The effect of gravity modulation and heat generation or absorption are considered while constant wall temperature boundary condition in the nanofluid are applied in this study. The mathematical formulation derived based on Tiwari and Das nanofluid model undertake boundary layer and Boussinesq approximations is then transform into non-dimensional governing equation using similarity transformation technique. Keller-box method is used to solve the non-dimensional governing equations. The velocity and temperature profile as well as skin friction and Nusset number near the stagnation point are presented graphically and discussed briefly under the influence of gravity modulation, curvature ratio, heat generation parameter and nanoparticles volume fraction. The result obtained show that the effect of heat generation gives rise to the skin frictions and Nusset number while additional of copper nanoparticles increase the thermal conductivity of the fluid