Journal & Issues

Volume 27 (2022): Issue 4 (December 2022)

Volume 27 (2022): Issue 3 (September 2022)

Volume 27 (2022): Issue 2 (June 2022)

Volume 27 (2022): Issue 1 (March 2022)

Volume 26 (2021): Issue 4 (December 2021)

Volume 26 (2021): Issue 3 (September 2021)

Volume 26 (2021): Issue 2 (June 2021)

Volume 26 (2021): Issue 1 (March 2021)

Volume 25 (2020): Issue 4 (December 2020)

Volume 25 (2020): Issue 3 (September 2020)

Volume 25 (2020): Issue 2 (June 2020)

Volume 25 (2020): Issue 1 (March 2020)

Volume 24 (2019): Issue 4 (December 2019)

Volume 24 (2019): Issue 3 (September 2019)

Volume 24 (2019): Issue 2 (June 2019)

Volume 24 (2019): Issue 1 (March 2019)

Volume 23 (2018): Issue 4 (November 2018)

Volume 23 (2018): Issue 3 (August 2018)

Volume 23 (2018): Issue 2 (May 2018)

Volume 23 (2018): Issue 1 (February 2018)

Volume 22 (2017): Issue 4 (December 2017)

Volume 22 (2017): Issue 3 (August 2017)

Volume 22 (2017): Issue 2 (May 2017)

Volume 22 (2017): Issue 1 (February 2017)

Volume 21 (2016): Issue 4 (December 2016)

Volume 21 (2016): Issue 3 (August 2016)

Volume 21 (2016): Issue 2 (May 2016)

Volume 21 (2016): Issue 1 (February 2016)

Volume 20 (2015): Issue 4 (December 2015)

Volume 20 (2015): Issue 3 (August 2015)

Volume 20 (2015): Issue 2 (May 2015)

Volume 20 (2015): Issue 1 (February 2015)

Volume 19 (2014): Issue 4 (December 2014)

Volume 19 (2014): Issue 3 (August 2014)

Volume 19 (2014): Issue 2 (May 2014)

Volume 19 (2014): Issue 1 (February 2014)

Volume 18 (2013): Issue 4 (December 2013)

Volume 18 (2013): Issue 3 (August 2013)

Volume 18 (2013): Issue 2 (June 2013)

Volume 18 (2013): Issue 1 (March 2013)

Journal Details
Format
Journal
eISSN
2353-9003
First Published
19 Apr 2013
Publication timeframe
4 times per year
Languages
English

Search

Volume 27 (2022): Issue 2 (June 2022)

Journal Details
Format
Journal
eISSN
2353-9003
First Published
19 Apr 2013
Publication timeframe
4 times per year
Languages
English

Search

15 Articles
Open Access

Influence of Slip Parameter, Viscous Dissipation and Joule Heating Effect on Boundary Layer Flow and Heat Transfer Over a Power-Law Stretching Wedge-Shaped Surface with the Correlation Coefficient and Multiple Regressions

Published Online: 14 Jun 2022
Page range: 1 - 21

Abstract

Abstract

The influence of slip parameter, viscous dissipation, and Joule heating parameter on MHD boundary layer nanofluid flow over a permeable wedge-shaped surface was analysed. The PDEs and the associated boundary conditions were transformed to a set of non-similar ODEs and the obtained system of equations was solved numerically with the help of the spectral quasi-linearization method (SQLM) by applying suitable software. This method helps to identify the accuracy and convergence of the present problem. The current numerical results were compared with previously published work and are found to be similar. The fluid velocity, fluid temperature, and nanoparticle concentration within the boundary layer region for various values of the parameters such as the slip effect, magnetic strength, Prandtl number, Lewis number, stretching ratio, viscous dissipation, suction, Brownian motion, Joule heating, heat generation, and thermophoresis are studied. It is observed that the Brownian motion, Joule heating, viscous dissipation, and thermophoresis lead to decreases in the heat and mass transfer rate. The skin friction coefficient enhances with slip, magnetic, permeability, and suction parameters, but reduces with the Brownian motion, wedge angle, and stretching ratio parameters whereas there is no effect of mixed convection, thermophoresis, heat generation parameters, the Prandtl and Eckert number.

Keywords

  • boundary layer
  • wedge angle
  • stretching surface
  • permeability
  • slip condition
Open Access

Heat Transfer By Natural Convection from a Heated Square Inner Cylinder to Its Elliptical Outer Enclosure Utilizing Nanofluids

Published Online: 14 Jun 2022
Page range: 22 - 34

Abstract

Abstract

In this paper a numerical study of natural convection of stationary laminar heat transfers in a horizontal ring between a heated square inner cylinder and a cold elliptical outer cylinder is presented. A Cu-water nanofluid flows through this annular space. Different values of the Rayleigh number and volume fraction of nanoparticles are studied. The system of equations governing the problem was solved numerically by the fluent calculation code based on the finite volume method and on the Boussinesq approximation. The interior and exterior surfaces are kept at constant temperature. The study is carried out for Rayleigh numbers ranging from 103 to 105. We have studied the effects of different Rayleigh numbers and volume fraction of nanoparticles on natural convection. The results are presented as isotherms, isocurrents, and local and mean Nusselt numbers. The aim of this study is to study the influence of the thermal Rayleigh number and volume fraction of nanoparticles on the heat transfer rate.

Keywords

  • natural convection
  • Rayleigh numbers
  • nanofluid
  • volume fraction
  • square elliptical
Open Access

Analysis of Deflection in Visco-Thermoelastic Beam Resonators Subjected to Harmonic Loading

Published Online: 14 Jun 2022
Page range: 35 - 52

Abstract

Abstract

This paper analyses the transverse deflection in a homogeneous, isotropic, visco-thermoelastic beam when subjected to harmonic load. The ends of the beam are considered at different boundary conditions (both axial ends clamped, both axial ends simply supported and left end clamped and right end free). The deflection has been studied by using the Laplace transform. Numerical computation of analytical expression of deflection obtained after Inverse Laplace transform has been done using MATLAB software. The graphical observations have been discussed under various boundary conditions for different values of time and length. The above work has applications in design of resonators.

Keywords

  • visco-thermoelastic
  • beam
  • loading
  • Laplace transform
Open Access

Reflection and Transmission in Non-Local Couple Stress Micropolar Thermoelastic Media

Published Online: 14 Jun 2022
Page range: 53 - 76

Abstract

Abstract

We have studied the problem of homogenous, isotropic non-local couple stress micropolar thermoelastic solid in the absence of body forces, couple density and heat resources. The reflection and transmission of waves at the interface of two distinct media have been investigated. It is observed that amplitude ratios of various reflected and transmitted waves are functions of wave number of incident waves and are affected by the non-local parameter of thermoelastic solid.

Keywords

  • non-local
  • thermoelastic solid
  • amplitude ratios
  • reflection
  • transmission
  • couple stress
  • wave number
Open Access

Heat Transfer in Oscillating Flow Through Porous Medium with Dissipative Heat

Published Online: 14 Jun 2022
Page range: 77 - 86

Abstract

Abstract

In this paper, heat transfer in flow between two horizontal parallel porous plates through a porous medium when the upper plate oscillates in its own plane has been analyzed taking into account the effect of viscous dissipation. An increment in the Prandtl number or Reynolds number results in an increment of the temperature profile. With an increase in viscous dissipative heat the temperature distribution decreases.

Keywords

  • injection
  • suction
  • transverse sinusoidal
  • transpiration cooling
  • viscous dissipation
Open Access

Effect of the Inner Diameter and Reynolds Number on the Recirculation Zone in Annular Jet Flow

Published Online: 14 Jun 2022
Page range: 87 - 97

Abstract

Abstract

In this paper, we focus on the effect of the inner diameter and Reynolds number on the recirculation zone in an annular jet flow with numerical simulation by resolving the Reynolds-averaged Navier-Stokes equations with the first closed model of turbulence k-epsilon. The annular jet plays an essential role in stabilizing the flame in the burner which is used in many industrial applications. The annular jet is characterized by the inner and outer diameter. In this study, three different inner diameters are adopted with constant width of the annular jet. We adopted also three different values of the Reynolds number show the effect of the Reynolds number on the recirculation zone. The simulation is realized by a CFD code which uses the finite element method. The results obtained from this study are in good agreement with the experimental data. Two recirculation zones are shown; a large recirculation zone at the outlet of the flow and a small recirculation zone just near the injection generated by the annular flow and the inner diameter Di; it is observed that the size of the recirculation zone increases when the inner diameter increases and the length of the recirculation zone depends only on the inner diameter. This recirculation zone is also affected by the Reynolds number with a very low variation of the recirculation length.

Keywords

  • jet flow
  • annular jet
  • recirculation zone
Open Access

A Study of MHD Fluid with Second Order Slip and Thermal Flow Over a Nonlinear Stretching Sheet

Published Online: 14 Jun 2022
Page range: 98 - 114

Abstract

Abstract

An electrically conducted viscous incompressible nanofluid flow caused by the nonlinear stretching surface with stagnation flow has been investigated numerically. The effect of Brownian motion and thermophoresis on the nanofluid is also incorporated. The governing partial differential equations with nonlinear second order boundary conditions are solved by the fourth order Runge-Kutta technique using MATLAB programming. The effect of the radiation parameter (Rd), stretching parameter (n), Brownian motion parameter (Nb), thermophoresis parameter (Nt) on temperature, velocity and mass transfer are shown graphically. The influence of some of these parameters on the local Nusselt number (− θ′(0)) and local Sherwood number (−ϕ′(0)) are shown by the graphs.

Keywords

  • stagnation point flow
  • second order slip boundary conditions
  • nonlinear stretching sheet
  • Runge-Kutta method
Open Access

Comparison of the Results for Calculation of Vortex Currents After Sudden Expansion of the Pipe with Different Diameters

Published Online: 14 Jun 2022
Page range: 115 - 123

Abstract

Abstract

In this work, a numerical study of a sharply expanding highly swirling flow is carried out using v2-f models based on the Comsol Multiphysics 5.6 software package and a two-fluid turbulence model. The results obtained are compared with known experimental data with different pipe diameters. The purpose of this work is to test the ability of models to describe anisotropic turbulence. It is shown that the two-fluid model is more suitable for studying such flows.

Keywords

  • two-fluid turbulence model
  • sudden expansion
  • velocity fluctuation
  • intensity of fluctuations
  • gas resistance
  • quasi-periodic regime
Open Access

Modeling and Optimization of Cutting Parameters When Turning EN-AW-1350 Aluminum Alloy

Published Online: 14 Jun 2022
Page range: 124 - 142

Abstract

Abstract

An experimental investigation is carried out to examine the effects of various cutting parameters on the response criteria when turning EN-AW-1350 aluminum alloy under dry cutting conditions. The experiments related to the analysis of the influence of turning parameters on the surface roughness (Ra) and material removal rate (MRR) were carried out according to the Taguchi L27 orthogonal array (313) approach. The analysis of variance (ANOVA) was applied to characterizing the main elements affecting response parameters. Finally, the desirability function (DP) was applied for a bi-objective optimization of the machining parameters with the objective of achieving a better surface finish (Ra) and a higher productivity (MRR). The results showed that the cutting speed is the most dominant factor affecting Ra followed by the feed rate and the depth of cut. Moreover, the Artificial Neural Network (ANN) approach is found to be more reliable and accurate than its Response Surface methodology (RSM) counterpart in terms of predicting and detecting the non-linearity of the surface roughness and material removal rate mathematical models. ANN provided prediction models with a precision benefit of 8.21% more than those determined by RSM. The latter is easier to use, and provides more information than ANN in terms of the impacts and contributions of the model terms.

Keywords

  • ANOVA
  • Artificial Neural Networks
  • chip shape
  • optimization
  • response surface methodology
Open Access

Promising Wing Vibration Measurement System Using MEMS IMUS and Kalman Filter Correction

Published Online: 14 Jun 2022
Page range: 143 - 157

Abstract

Abstract

Nowadays, there is still a need for the development of a high-precision vibration measurement system for aircraft wings. By analyzing the wing vibration characteristics a lot of aviation studies could be conducted, including the wing health monitoring, the fluttering phenomenon and so on. This paper presents preliminary results of the research carried out toward building a promising system designed to measure vibration parameters of aircraft wing. Comparing it with the existing analogue systems, the proposed system features the use of approaches that are traditional for solving orientation and navigation problems for vibration measurements. The paper presents the basic structure of the system, the fundamentals of its operation, the mathematical errors models of its main components, the correction algorithms using optimal Kalman filter. Finally, the initial simulation results of system operation are shown, demonstrating the expected accuracy characteristics of the system, which confirms its effectiveness and the prospects of the chosen direction of research.

Keywords

  • aircraft wing
  • vibration measurement
  • Kalman filter
  • MEMS IMU
  • closed-loop optimal correction
Open Access

Combined Effects of Helical Force and Rotation on Stationary Convection of a Binary Ferrofluid in a Porous Medium.

Published Online: 14 Jun 2022
Page range: 158 - 176

Abstract

Abstract

This work studies the simultaneous effects of helical force, rotation and porosity on the appearance of stationary convection in a binary mixture of a ferrofluid and on the size of convection cells. We have determined the analytical expression of the Rayleigh number of the system as a function of the dimensionless parameters. The effect of each parameter on the system is studied. The consideration of the simultaneous effect of the basic characteristics made it possible to determine the evolution of the convection threshold in the ferrofluid and then the size of convection cells. The analyzes of the various results obtained allowed us to deduce whether the convection sets in quickly or with a delay when the various effects taken into account in the study are considered simultaneously.

Keywords

  • helical force
  • stationary convection
  • binary mixture of ferrofluid
  • porous medium
  • rotation
Open Access

On a Couple-Stress Rivlin-Ericksen Ferromagnetic Fluid Heated from Below with Varying Gravity, Rotation, Magnetic Field and Suspended Particles Flowing Through a Porous Medium

Published Online: 14 Jun 2022
Page range: 177 - 198

Abstract

Abstract

The thermal instability of a couple-stress Rivlin-Ericksen ferromagnetic fluid with varying gravity field, suspended particles, rotation and magnetic field flowing through a porous medium is investigated. The dispersion relation has been developed and solved analytically using the normal mode approach and linear stability theory. The effect of suspended particles, rotation, couple stress, permeability and magnetic field on the fluid layer has been investigated. For stationary conventions, it is found that suspended particles always have a destabilizing effect for λ>0 and a stabilizing effect for λ<0 and couple-stress, magnetic field and permeability of the medium have a stabilizing effect on the thermal instability under certain conditions. In the absence of the rotation couple-stress has a stabilizing effect if λ >0 and a destabilizing effect if λ<0. Rotation has a stabilizing effect if λ >0 and a destabilizing effect if λ<0. In the absence of rotation permeability has a stabilizing effect if λ<0 and a destabilizing effect if λ>0. Magnetisation always has a stabilizing effect (λ>0 or λ<0).

Keywords

  • thermal instability
  • magnetic field
  • couple-stress fluid
  • ferromagnetic fluid
  • suspended particles
Open Access

Numerical Study on Thermal Performance of Water Flow in a Twisted Duct Heat Exchanger

Published Online: 14 Jun 2022
Page range: 199 - 216

Abstract

Abstract

This paper presents a numerical study of heat transfer through a downstream annulus using water as the working fluid within the laminar flow region. The annulus consisted of an outer twisted square duct and an inner circular pipe. A three-dimensional formulation was used to solve the Navier-Stokes equations numerically for the laminar flow system with a low Reynolds number. Three parameters were used in the numerical simulation: the length of the twisted square (a: 6.6, 8.2 10.2, 12.6 mm) the inner diameter of the inner circular pipe (d: 19, 21, 23 and 25 mm); and the twist angle (θ: 0° (smooth), 45°, 60°, and 90°). Numerical calculations were conducted on sixteen twisted square duct heat exchangers, with water flowing within a Reynolds number range of 2201100. The results were illustrated as a profile of the thermal enhancement factor, the friction factor and the Nusselt number. The results show that the twisted outer duct of the heat exchanger can create a swirl flow along the length of the heat exchanger. It also caused a boundary layer separation-reattachment on the wall of the inner pipe. Moreover, an increase in the twist angle increased the Nusselt number by 20 %, and the friction factor was also increased as the annular gap of the heat exchanger decreased.

Keywords

  • mixed convection
  • twisted square duct
  • heat exchanger
  • laminar flow
Open Access

Influence of Welding Parameters of Resistance Spot Welding on Joining Aluminum with Copper

Published Online: 14 Jun 2022
Page range: 217 - 225

Abstract

Abstract

The resistance spot welding (RSW) method was used to join aluminum alloy AA 1050 and copper alloy UNS C50100 sheets. Mechanical properties of the joints were examined. The influence of welding process parameters on tensile shear force of the joints was discussed. The design of experiments (DOE) method was used to analyze the influence of welding parameters on the mechanical properties of the joints. Three RSW parameters were used: welding current, squeeze time, and welding time. The results showed that the joint shear stress increased with increasing the welding current until a value of 12000 Amp. Then the shear stress decreased. The tensile shear stress increased with increasing the welding and squeeze time. As a consequence, it can be possible to weld copper with aluminum by RSW.

Keywords

  • resistance spot welding (RSW)
  • aluminum (Al)
  • copper (Cu)
  • RSW parameter
  • DOE
Open Access

Chemical Reaction and Mhd Flow for Magnetic Field Effect on Heat and Mass Transfer of Fluid Flow Through a Porous Medium Onto a Moving Vertical Plate

Published Online: 14 Jun 2022
Page range: 226 - 244

Abstract

Abstract

This article discusses the effect of heat and mass transfer in a boundary layer flow in the presence of a magnetic field of an electrically conducting and viscous fluid as it passes through a porous medium containing a heat source and a chemical reaction. By employing similarity variables, the governing equations are changed into nonlinear ordinary differential equations(ODEs). To solve the obtained equations numerically the Keller box method is used. Numerical and graphical representations of the results of different parameter values governing the flow system are given. The non-dimensional distributions of velocity, heat, and concentration are depicted graphically, while the Nusselt number, Sherwood number, and skin friction are determined numerically.

Keywords

  • MHD
  • chemical reaction
  • Keller box method
  • magnetic field
  • thermal radiation
15 Articles
Open Access

Influence of Slip Parameter, Viscous Dissipation and Joule Heating Effect on Boundary Layer Flow and Heat Transfer Over a Power-Law Stretching Wedge-Shaped Surface with the Correlation Coefficient and Multiple Regressions

Published Online: 14 Jun 2022
Page range: 1 - 21

Abstract

Abstract

The influence of slip parameter, viscous dissipation, and Joule heating parameter on MHD boundary layer nanofluid flow over a permeable wedge-shaped surface was analysed. The PDEs and the associated boundary conditions were transformed to a set of non-similar ODEs and the obtained system of equations was solved numerically with the help of the spectral quasi-linearization method (SQLM) by applying suitable software. This method helps to identify the accuracy and convergence of the present problem. The current numerical results were compared with previously published work and are found to be similar. The fluid velocity, fluid temperature, and nanoparticle concentration within the boundary layer region for various values of the parameters such as the slip effect, magnetic strength, Prandtl number, Lewis number, stretching ratio, viscous dissipation, suction, Brownian motion, Joule heating, heat generation, and thermophoresis are studied. It is observed that the Brownian motion, Joule heating, viscous dissipation, and thermophoresis lead to decreases in the heat and mass transfer rate. The skin friction coefficient enhances with slip, magnetic, permeability, and suction parameters, but reduces with the Brownian motion, wedge angle, and stretching ratio parameters whereas there is no effect of mixed convection, thermophoresis, heat generation parameters, the Prandtl and Eckert number.

Keywords

  • boundary layer
  • wedge angle
  • stretching surface
  • permeability
  • slip condition
Open Access

Heat Transfer By Natural Convection from a Heated Square Inner Cylinder to Its Elliptical Outer Enclosure Utilizing Nanofluids

Published Online: 14 Jun 2022
Page range: 22 - 34

Abstract

Abstract

In this paper a numerical study of natural convection of stationary laminar heat transfers in a horizontal ring between a heated square inner cylinder and a cold elliptical outer cylinder is presented. A Cu-water nanofluid flows through this annular space. Different values of the Rayleigh number and volume fraction of nanoparticles are studied. The system of equations governing the problem was solved numerically by the fluent calculation code based on the finite volume method and on the Boussinesq approximation. The interior and exterior surfaces are kept at constant temperature. The study is carried out for Rayleigh numbers ranging from 103 to 105. We have studied the effects of different Rayleigh numbers and volume fraction of nanoparticles on natural convection. The results are presented as isotherms, isocurrents, and local and mean Nusselt numbers. The aim of this study is to study the influence of the thermal Rayleigh number and volume fraction of nanoparticles on the heat transfer rate.

Keywords

  • natural convection
  • Rayleigh numbers
  • nanofluid
  • volume fraction
  • square elliptical
Open Access

Analysis of Deflection in Visco-Thermoelastic Beam Resonators Subjected to Harmonic Loading

Published Online: 14 Jun 2022
Page range: 35 - 52

Abstract

Abstract

This paper analyses the transverse deflection in a homogeneous, isotropic, visco-thermoelastic beam when subjected to harmonic load. The ends of the beam are considered at different boundary conditions (both axial ends clamped, both axial ends simply supported and left end clamped and right end free). The deflection has been studied by using the Laplace transform. Numerical computation of analytical expression of deflection obtained after Inverse Laplace transform has been done using MATLAB software. The graphical observations have been discussed under various boundary conditions for different values of time and length. The above work has applications in design of resonators.

Keywords

  • visco-thermoelastic
  • beam
  • loading
  • Laplace transform
Open Access

Reflection and Transmission in Non-Local Couple Stress Micropolar Thermoelastic Media

Published Online: 14 Jun 2022
Page range: 53 - 76

Abstract

Abstract

We have studied the problem of homogenous, isotropic non-local couple stress micropolar thermoelastic solid in the absence of body forces, couple density and heat resources. The reflection and transmission of waves at the interface of two distinct media have been investigated. It is observed that amplitude ratios of various reflected and transmitted waves are functions of wave number of incident waves and are affected by the non-local parameter of thermoelastic solid.

Keywords

  • non-local
  • thermoelastic solid
  • amplitude ratios
  • reflection
  • transmission
  • couple stress
  • wave number
Open Access

Heat Transfer in Oscillating Flow Through Porous Medium with Dissipative Heat

Published Online: 14 Jun 2022
Page range: 77 - 86

Abstract

Abstract

In this paper, heat transfer in flow between two horizontal parallel porous plates through a porous medium when the upper plate oscillates in its own plane has been analyzed taking into account the effect of viscous dissipation. An increment in the Prandtl number or Reynolds number results in an increment of the temperature profile. With an increase in viscous dissipative heat the temperature distribution decreases.

Keywords

  • injection
  • suction
  • transverse sinusoidal
  • transpiration cooling
  • viscous dissipation
Open Access

Effect of the Inner Diameter and Reynolds Number on the Recirculation Zone in Annular Jet Flow

Published Online: 14 Jun 2022
Page range: 87 - 97

Abstract

Abstract

In this paper, we focus on the effect of the inner diameter and Reynolds number on the recirculation zone in an annular jet flow with numerical simulation by resolving the Reynolds-averaged Navier-Stokes equations with the first closed model of turbulence k-epsilon. The annular jet plays an essential role in stabilizing the flame in the burner which is used in many industrial applications. The annular jet is characterized by the inner and outer diameter. In this study, three different inner diameters are adopted with constant width of the annular jet. We adopted also three different values of the Reynolds number show the effect of the Reynolds number on the recirculation zone. The simulation is realized by a CFD code which uses the finite element method. The results obtained from this study are in good agreement with the experimental data. Two recirculation zones are shown; a large recirculation zone at the outlet of the flow and a small recirculation zone just near the injection generated by the annular flow and the inner diameter Di; it is observed that the size of the recirculation zone increases when the inner diameter increases and the length of the recirculation zone depends only on the inner diameter. This recirculation zone is also affected by the Reynolds number with a very low variation of the recirculation length.

Keywords

  • jet flow
  • annular jet
  • recirculation zone
Open Access

A Study of MHD Fluid with Second Order Slip and Thermal Flow Over a Nonlinear Stretching Sheet

Published Online: 14 Jun 2022
Page range: 98 - 114

Abstract

Abstract

An electrically conducted viscous incompressible nanofluid flow caused by the nonlinear stretching surface with stagnation flow has been investigated numerically. The effect of Brownian motion and thermophoresis on the nanofluid is also incorporated. The governing partial differential equations with nonlinear second order boundary conditions are solved by the fourth order Runge-Kutta technique using MATLAB programming. The effect of the radiation parameter (Rd), stretching parameter (n), Brownian motion parameter (Nb), thermophoresis parameter (Nt) on temperature, velocity and mass transfer are shown graphically. The influence of some of these parameters on the local Nusselt number (− θ′(0)) and local Sherwood number (−ϕ′(0)) are shown by the graphs.

Keywords

  • stagnation point flow
  • second order slip boundary conditions
  • nonlinear stretching sheet
  • Runge-Kutta method
Open Access

Comparison of the Results for Calculation of Vortex Currents After Sudden Expansion of the Pipe with Different Diameters

Published Online: 14 Jun 2022
Page range: 115 - 123

Abstract

Abstract

In this work, a numerical study of a sharply expanding highly swirling flow is carried out using v2-f models based on the Comsol Multiphysics 5.6 software package and a two-fluid turbulence model. The results obtained are compared with known experimental data with different pipe diameters. The purpose of this work is to test the ability of models to describe anisotropic turbulence. It is shown that the two-fluid model is more suitable for studying such flows.

Keywords

  • two-fluid turbulence model
  • sudden expansion
  • velocity fluctuation
  • intensity of fluctuations
  • gas resistance
  • quasi-periodic regime
Open Access

Modeling and Optimization of Cutting Parameters When Turning EN-AW-1350 Aluminum Alloy

Published Online: 14 Jun 2022
Page range: 124 - 142

Abstract

Abstract

An experimental investigation is carried out to examine the effects of various cutting parameters on the response criteria when turning EN-AW-1350 aluminum alloy under dry cutting conditions. The experiments related to the analysis of the influence of turning parameters on the surface roughness (Ra) and material removal rate (MRR) were carried out according to the Taguchi L27 orthogonal array (313) approach. The analysis of variance (ANOVA) was applied to characterizing the main elements affecting response parameters. Finally, the desirability function (DP) was applied for a bi-objective optimization of the machining parameters with the objective of achieving a better surface finish (Ra) and a higher productivity (MRR). The results showed that the cutting speed is the most dominant factor affecting Ra followed by the feed rate and the depth of cut. Moreover, the Artificial Neural Network (ANN) approach is found to be more reliable and accurate than its Response Surface methodology (RSM) counterpart in terms of predicting and detecting the non-linearity of the surface roughness and material removal rate mathematical models. ANN provided prediction models with a precision benefit of 8.21% more than those determined by RSM. The latter is easier to use, and provides more information than ANN in terms of the impacts and contributions of the model terms.

Keywords

  • ANOVA
  • Artificial Neural Networks
  • chip shape
  • optimization
  • response surface methodology
Open Access

Promising Wing Vibration Measurement System Using MEMS IMUS and Kalman Filter Correction

Published Online: 14 Jun 2022
Page range: 143 - 157

Abstract

Abstract

Nowadays, there is still a need for the development of a high-precision vibration measurement system for aircraft wings. By analyzing the wing vibration characteristics a lot of aviation studies could be conducted, including the wing health monitoring, the fluttering phenomenon and so on. This paper presents preliminary results of the research carried out toward building a promising system designed to measure vibration parameters of aircraft wing. Comparing it with the existing analogue systems, the proposed system features the use of approaches that are traditional for solving orientation and navigation problems for vibration measurements. The paper presents the basic structure of the system, the fundamentals of its operation, the mathematical errors models of its main components, the correction algorithms using optimal Kalman filter. Finally, the initial simulation results of system operation are shown, demonstrating the expected accuracy characteristics of the system, which confirms its effectiveness and the prospects of the chosen direction of research.

Keywords

  • aircraft wing
  • vibration measurement
  • Kalman filter
  • MEMS IMU
  • closed-loop optimal correction
Open Access

Combined Effects of Helical Force and Rotation on Stationary Convection of a Binary Ferrofluid in a Porous Medium.

Published Online: 14 Jun 2022
Page range: 158 - 176

Abstract

Abstract

This work studies the simultaneous effects of helical force, rotation and porosity on the appearance of stationary convection in a binary mixture of a ferrofluid and on the size of convection cells. We have determined the analytical expression of the Rayleigh number of the system as a function of the dimensionless parameters. The effect of each parameter on the system is studied. The consideration of the simultaneous effect of the basic characteristics made it possible to determine the evolution of the convection threshold in the ferrofluid and then the size of convection cells. The analyzes of the various results obtained allowed us to deduce whether the convection sets in quickly or with a delay when the various effects taken into account in the study are considered simultaneously.

Keywords

  • helical force
  • stationary convection
  • binary mixture of ferrofluid
  • porous medium
  • rotation
Open Access

On a Couple-Stress Rivlin-Ericksen Ferromagnetic Fluid Heated from Below with Varying Gravity, Rotation, Magnetic Field and Suspended Particles Flowing Through a Porous Medium

Published Online: 14 Jun 2022
Page range: 177 - 198

Abstract

Abstract

The thermal instability of a couple-stress Rivlin-Ericksen ferromagnetic fluid with varying gravity field, suspended particles, rotation and magnetic field flowing through a porous medium is investigated. The dispersion relation has been developed and solved analytically using the normal mode approach and linear stability theory. The effect of suspended particles, rotation, couple stress, permeability and magnetic field on the fluid layer has been investigated. For stationary conventions, it is found that suspended particles always have a destabilizing effect for λ>0 and a stabilizing effect for λ<0 and couple-stress, magnetic field and permeability of the medium have a stabilizing effect on the thermal instability under certain conditions. In the absence of the rotation couple-stress has a stabilizing effect if λ >0 and a destabilizing effect if λ<0. Rotation has a stabilizing effect if λ >0 and a destabilizing effect if λ<0. In the absence of rotation permeability has a stabilizing effect if λ<0 and a destabilizing effect if λ>0. Magnetisation always has a stabilizing effect (λ>0 or λ<0).

Keywords

  • thermal instability
  • magnetic field
  • couple-stress fluid
  • ferromagnetic fluid
  • suspended particles
Open Access

Numerical Study on Thermal Performance of Water Flow in a Twisted Duct Heat Exchanger

Published Online: 14 Jun 2022
Page range: 199 - 216

Abstract

Abstract

This paper presents a numerical study of heat transfer through a downstream annulus using water as the working fluid within the laminar flow region. The annulus consisted of an outer twisted square duct and an inner circular pipe. A three-dimensional formulation was used to solve the Navier-Stokes equations numerically for the laminar flow system with a low Reynolds number. Three parameters were used in the numerical simulation: the length of the twisted square (a: 6.6, 8.2 10.2, 12.6 mm) the inner diameter of the inner circular pipe (d: 19, 21, 23 and 25 mm); and the twist angle (θ: 0° (smooth), 45°, 60°, and 90°). Numerical calculations were conducted on sixteen twisted square duct heat exchangers, with water flowing within a Reynolds number range of 2201100. The results were illustrated as a profile of the thermal enhancement factor, the friction factor and the Nusselt number. The results show that the twisted outer duct of the heat exchanger can create a swirl flow along the length of the heat exchanger. It also caused a boundary layer separation-reattachment on the wall of the inner pipe. Moreover, an increase in the twist angle increased the Nusselt number by 20 %, and the friction factor was also increased as the annular gap of the heat exchanger decreased.

Keywords

  • mixed convection
  • twisted square duct
  • heat exchanger
  • laminar flow
Open Access

Influence of Welding Parameters of Resistance Spot Welding on Joining Aluminum with Copper

Published Online: 14 Jun 2022
Page range: 217 - 225

Abstract

Abstract

The resistance spot welding (RSW) method was used to join aluminum alloy AA 1050 and copper alloy UNS C50100 sheets. Mechanical properties of the joints were examined. The influence of welding process parameters on tensile shear force of the joints was discussed. The design of experiments (DOE) method was used to analyze the influence of welding parameters on the mechanical properties of the joints. Three RSW parameters were used: welding current, squeeze time, and welding time. The results showed that the joint shear stress increased with increasing the welding current until a value of 12000 Amp. Then the shear stress decreased. The tensile shear stress increased with increasing the welding and squeeze time. As a consequence, it can be possible to weld copper with aluminum by RSW.

Keywords

  • resistance spot welding (RSW)
  • aluminum (Al)
  • copper (Cu)
  • RSW parameter
  • DOE
Open Access

Chemical Reaction and Mhd Flow for Magnetic Field Effect on Heat and Mass Transfer of Fluid Flow Through a Porous Medium Onto a Moving Vertical Plate

Published Online: 14 Jun 2022
Page range: 226 - 244

Abstract

Abstract

This article discusses the effect of heat and mass transfer in a boundary layer flow in the presence of a magnetic field of an electrically conducting and viscous fluid as it passes through a porous medium containing a heat source and a chemical reaction. By employing similarity variables, the governing equations are changed into nonlinear ordinary differential equations(ODEs). To solve the obtained equations numerically the Keller box method is used. Numerical and graphical representations of the results of different parameter values governing the flow system are given. The non-dimensional distributions of velocity, heat, and concentration are depicted graphically, while the Nusselt number, Sherwood number, and skin friction are determined numerically.

Keywords

  • MHD
  • chemical reaction
  • Keller box method
  • magnetic field
  • thermal radiation

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