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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
ISSN
1734-4492
First Published
19 Apr 2013
Publication timeframe
4 times per year
Languages
English

Search

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

Journal Details
Format
Journal
eISSN
2353-9003
ISSN
1734-4492
First Published
19 Apr 2013
Publication timeframe
4 times per year
Languages
English

Search

15 Articles
Open Access

A Numerical Examination of an Unsteady Nonlinear MHD Flow in the Presence of Thermal Radiation and Heat Generation

Published Online: 29 Jan 2021
Page range: 1 - 17

Abstract

Abstract

In this study, the spectral perturbation method and the spectral relaxation method are used to solve the nonlinear differential equations of an unsteady nonlinear MHD flow in the presence of thermal radiation and heat generation. The SPM is mainly based on series expansion, generating series approximation coupled with the Chebyshev spectral method. The numerical results generated using the spectral perturbation method were compared with those found in the literature, and the two results were in good agreement.

Keywords

  • unsteady MHD flow
  • spectral perturbation method
  • spectral relaxation method
  • thermal radiation
  • heat generation
Open Access

Initial Geometric Imperfections: A Robust, Closed-Section Cold-Formed Box Profile Application Subject to Local Buckling

Published Online: 29 Jan 2021
Page range: 18 - 44

Abstract

Abstract

Initial geometric imperfections are important for simulating local buckling in numerical models. References are found in the technical literature regarding open-section cold formed profiles. This work presents new procedures applied to a robust and closed-section cold formed profile subject to local buckling, and the use of procedures described in the technical literature already successfully used for open section profiles. The difference of this work in relation to the research already carried out is in the type of profile studied, in the mode of failure of the same and in the form of determination of the initial imperfections. The object of study of this work is a closed-section cold formed box profile with a short length when compared with its cross section and with local buckling failure mode. The strategies used in the present work to consider the initial geometric imperfections were to perform the linear stability analysis using the finite element method to obtain the local buckling mode that represents the deformed box profile geometry, to apply a multiplication factor in the displacements, replace the new geometry node coordinates for all profile nodes to induce the local buckling deformation mode, with model validation through experimental testing and the Effective Width Method (MLE) (ABNT NBR 14762 [1]). Finally, using the results of the collapse load of the experimental trial as a basis, it was possible to compare the results obtained by MLE and MEF. Thus, the presentation of this work used a methodology that describes the local buckling behavior and verified the precepts of the existing norms on the subject, combining theoretical and experimental methods, as they bring a better understanding of the structural problem in question.

Keywords

  • Bucket elevator
  • box profile
  • local buckling
  • finite element method
  • experimental test
  • initial geometric imperfections
Open Access

Computer Analysis of Dynamic Reliability of Some Concrete Beam Structure Exhibiting Random Damping

Published Online: 29 Jan 2021
Page range: 45 - 64

Abstract

Abstract

An efficiency of the generalized tenth order stochastic perturbation technique in determination of the basic probabilistic characteristics of up to the fourth order of dynamic response of Euler-Bernoulli beams with Gaussian uncertain damping is verified in this work. This is done on civil engineering application of a two-bay reinforced concrete beam using the Stochastic Finite Element Method implementation and its contrast with traditional Monte-Carlo simulation based Finite Element Method study and also with the semi-analytical probabilistic approach. The special purpose numerical implementation of the entire Stochastic perturbation-based Finite Element Method has been entirely programmed in computer algebra system MAPLE 2019 using Runge-Kutta-Fehlberg method. Further usage of the proposed technique to analyze stochastic reliability of the given structure subjected to dynamic oscillatory excitation is also included and discussed here because of a complete lack of the additional detailed demands in the current European designing codes.

Keywords

  • reliability analysis
  • Stochastic Finite Element Method
  • generalized stochastic perturbation technique
  • forced vibrations
  • Runge-Kutta-Fehlberg method
Open Access

Capture Efficiency of Magnetically Labeled Particles Traveling Through an Intracranial Aneurysm

Published Online: 29 Jan 2021
Page range: 65 - 75

Abstract

Abstract

Cell manipulation using external magnetic fields has been proposed to accelerate the neck reendothelization of saccular unruptured stented intracranial aneurysms. This work presents a computational fluid dynamics (CFD) model of a Saccular Brain Aneurysm that incorporates a helicoidal stent. An Eulerian-Lagrangian model implemented in ANSYS-Fluent is used to simulate the hemodynamics in the aneurysm. In silico studies have been conducted to describe the incidence of the magnetic field direction, frequency and amplitude on the blood hemodynamics and particle capture efficiency, when an external magnetic field is used to trap magnetically labeled particles traveling through the aneurysm. It is found that the magnetic field direction affects the particle concentration in the target region. Simulation results show that the highest particle capture efficiency is obtained with a 1T magnetic field amplitude in an open bore MRI scanner, when a permanent magnet is used.

Keywords

  • endothelization
  • particle manipulation
  • computational fluid dynamics
  • magnetohydrodynamics
Open Access

Reduced Differential Transform Method for Thermoelastic Problem in Hyperbolic Heat Conduction Domain

Published Online: 29 Jan 2021
Page range: 76 - 87

Abstract

Abstract

In the present study, we have applied the reduced differential transform method to solve the thermoelastic problem which reduces the computational efforts. In the study, the temperature distribution in a two-dimensional rectangular plate follows the hyperbolic law of heat conduction. We have obtained the generalized solution for thermoelastic field and temperature field by considering non-homogeneous boundary conditions in the x and y direction. Using this method one can obtain a solution in series form. The special case is considered to show the effectiveness of the present method. And also, the results are shown numerically and graphically. The study shows that this method provides an analytical approximate solution in very easy steps and requires little computational work.

Keywords

  • hyperbolic heat conduction
  • thermal stresses
  • thermal displacement
  • rectangular plate
  • reduced differential transform
Open Access

Exact Solutions for Fractionalized Second Grade Fluid Flows with Boundary Slip Effects

Published Online: 29 Jan 2021
Page range: 88 - 103

Abstract

Abstract

In this paper, an exact analytical solution for the motion of fractionalized second grade fluid flows moving over accelerating plate under the influence of slip has been obtained. A coupled system of partial differential equations representing the equation of motion has been re-written in terms of fractional derivatives form by using the Caputo fractional operator. The Discrete Laplace transform method has been employed for computing the expressions for the velocity field u(y, t) and the corresponding shear stress τ (y, t). The obtained solutions for the velocity field and the shear stress have been written in terms of Wright generalized hypergeometric function pψq and are expressed as a sum of the slip contribution and the corresponding no-slip contribution. In addition, the solutions for a fractionalized, ordinary second grade fluid and Newtonian fluid in the absence of slip effect have also been obtained as special case. Finally, the effect of different physical parameters has been demonstrated through graphical illustrations.

Keywords

  • second grade fluid
  • Caputo fractional operator
  • slip effects
  • discrete Laplace transform
Open Access

Hydrodynamic Analysis of Noise Propagation By the High Skew Marine Propeller Working in Non-Uniform Inflow

Published Online: 29 Jan 2021
Page range: 104 - 121

Abstract

Abstract

Being able to predict ship and marine propulsion noise is an important issue for naval architectures and the international maritime community. The main objective of this paper is the numerical investigation on the noise propagation by the high skew marine propeller working in a non-uniform inflow via RANS solver in the broadband frequency range. The pressure fluctuations were monitored at three points on the propeller blade, then by using the FFT operator we computed the blade passing frequency (BPF) for different propeller loading conditions. Based on these pressure pulses and adopting the Fowcs Williams-Hawking model we calculated noise radiated at the monitoring points. The results showed the BPF and noise level increased by increasing the load on the blades and we also observed that the noise generated at the leading edge was greater than at other points. Furthermore, the study of pressure fluctuations showed the propeller tip has more pressure variations in one revolution than other regions of the propeller surface.

Keywords

  • Noise
  • high skew marine propeller
  • pressure fluctuating
  • blade passing frequency
Open Access

Heat Transfer Effects on Free Convection of Viscous Dissipative Fluid Flow Over an Inclined Plate with Thermal Radiation in the Presence of Induced Magnetic Field

Published Online: 29 Jan 2021
Page range: 122 - 134

Abstract

Abstract

The principal objective of the present paper is to know the reaction of thermal radiation and the effects of magnetic fields on a viscous dissipative free convection fluid flow past an inclined infinite plate in the presence of an induced magnetic field. The Galerkin finite element technique is applied to solve the nonlinear coupled partial differential equations and effects of thermal radiation and other physical and flow parameters on velocity, induced magnetic field, along with temperature profiles are explained through graphs. It is noticed that as the thermal radiation increases velocity and temperature profiles decrease and the induced magnetic field profiles increases.

Keywords

  • thermal radiation
  • induced magnetic field
  • magnetic Prandtl number
  • free convection
  • Galerkin finite element method
  • viscous dissipation
Open Access

The Effect of Thermal Modulation on Double Diffusive Convection in the Presence of Applied Magnetic Field and Internal Heat Source

Published Online: 29 Jan 2021
Page range: 135 - 155

Abstract

Abstract

The investigation of thermal modulation on double-diffusive stationary convection in the presence of an applied magnetic field and internal heating is carried out. A weakly nonlinear stability analysis has been performed using the finite-amplitude Ginzburg-Landau model. This finite amplitude of convection is obtained at the third order of the system. The study considers three different forms of temperature modulations. OPM-out of phase modulation, LBMO-lower boundary modulation, IPM-in phase modulation. The finite-amplitude is a function of amplitude δT, frequency ω and the phase difference θ. The effects of δT and ω on heat/mass transports have been analyzed and depicted graphically. The study shows that heat/mass transports can be controlled effectively by thermal modulation. Further, it is found that the internal Rayleigh number Ri enhances heat transfer and reduces the mass transfer in the system.

Keywords

  • thermal modulation
  • weak nonlinear analysis
  • internal heating
  • Newtonian fluid
  • double diffusive convection
Open Access

The Onset of Soret Driven Ferrothermoconvective Instability in the Presence of Darcy Porous Medium with Anisotropy Effect and MFD Viscosity

Published Online: 29 Jan 2021
Page range: 156 - 177

Abstract

Abstract

The effect of magnetic field dependent (MFD) viscosity on Soret driven ferrothermohaline convection in a densely packed anisotropic porous medium has been studied. The Soret effect is focused on the system. A linear stability analysis is carried out using a normal mode technique and a perturbation method is applied. It is found that a stationary mode is favorable for the Darcy model. Vertical anisotropy tends to destabilize the system and the magnetization effect is found to stabilize the system. It is also found that the MFD viscosity delays the onset of convection. Numerical computations are made and illustrated graphically.

Keywords

  • anisotropy effect
  • Darcy model
  • MFD viscosity
  • porous medium
  • Soret coefficient
Open Access

Unified Methodology for Strength and Stress Analysis of Structural Concrete Members

Published Online: 29 Jan 2021
Page range: 178 - 200

Abstract

Abstract

In this paper, a methodology is presented for determining the stress and strain in structural concrete sections, also, for estimating the ultimate combination of axial forces and bending moments that produce failure. The structural concrete member may have a cross-section with an arbitrary configuration, the concrete region may consist of a set of subregions having different characteristics (i.e., different grades of concretes, or initially identical, but working with different stress-strain diagrams due to the effect of indirect reinforcement or the effect of confinement, etc.). This methodology is considering the tensile strain softening and tension stiffening of concrete in addition to the tension stiffening of steel bars due to the tensile resistance of the surrounding concrete layer. A comparison of experimental and numerical data indicates that the results, obtained based on this methodology, are highly reliable and highly informative.

Keywords

  • curvature
  • secant modulus
  • uniaxial stress-strain
  • extinction of prestressing
  • cracking
  • deformability
Open Access

Effect of Magnetic Field on Thermosolutal Instability of Rotating Ferromagnetic Fluid Under Varying Gravity Field

Published Online: 29 Jan 2021
Page range: 201 - 214

Abstract

Abstract

This paper deals with the theoretical investigation of the effect of a magnetic field, rotation and magnetization on a ferromagnetic fluid under varying gravity field. To find the exact solution for a ferromagnetic fluid layer contained between two free boundaries, we have used a linear stability analysis and normal mode analysis method. For the case of stationary convection, a stable solute gradient has a stabilizing effect, while rotation has a stabilizing effect if λ>0 and destabilizing effect if λ<0. Further, the magnetic field is discovered to have both a stabilizing and destabilizing effect for both λ>0 and λ<0. It is likewise discovered that magnetization has a stabilizing effect for both λ>0 and λ<0 in the absence of the stable solute gradient. Graphs have been plotted by giving numerical values of various parameters. In the absence of rotation, magnetic field and stable solute gradient, the principle of exchange of stabilities is found to hold true for certain conditions.

Keywords

  • thermosolutal instability
  • ferromagnetic fluid
  • rotation
  • magnetic field
  • magnetization
Open Access

Effects of Pressure Work Over a Semi-Infinite Vertical Oscillating Cylinder

Published Online: 29 Jan 2021
Page range: 215 - 225

Abstract

Abstract

An arithmetical methodology is used to study natural convection with properties of pressure work over a semi-infinite vertical oscillating cylinder. The governing partial differential equations are set up and the resulting equations are changed into a non-dimensional form using the proper non-dimensional quantities. The set of non-dimensional partial differential equations is solved arithmetically using a well-organized method known as the Crank-Nicolson method. The velocity, as well as temperature profiles for different values of parameters are studied with the assistance of graphs.

Keywords

  • cylinder
  • finite difference
  • pressure work
  • oscillating
  • skin friction
Open Access

Slowly Vibrating Axially Symmetric Bodies-Transverse Flow

Published Online: 29 Jan 2021
Page range: 226 - 250

Abstract

Abstract

Stokes drag on axially symmetric bodies vibrating slowly along the axis of symmetry placed under a uniform transverse flow of the Newtonian fluid is calculated. The axially symmetric bodies of revolution are considered with the condition of continuously turning tangent. The results of drag on sphere, spheroid, deformed sphere, egg-shaped body, cycloidal body, Cassini oval, and hypocycloidal body are found to be new. The numerical values of frictional drag on a slowly vibrating needle shaped body and flat circular disk are calculated as particular cases of deformed sphere.

Keywords

  • Stokes drag
  • axially symmetric bodies
  • Newtonian fluid
  • axial flow
Open Access

Effects of Stenosis and Dilatation on Flow of Blood Mixed with Suspended Nanoparticles: A Study Using Homotopy Technique

Published Online: 29 Jan 2021
Page range: 251 - 265

Abstract

Abstract

The paper deals with a theoretical study on blood flow in a stenosed segment of an artery, when blood is mixed with nano-particles. Blood is treated here as a couple stress fluid. Stenosis is known to impede blood flow and to be the cause of different cardiac diseases. Since the arterial wall is weakened due to arterial stenosis, it may lead to dilatation /aneurysm. The homotopy perturbation technique is employed to determine the solution to the problem for the case of mild stenosis. Analytical expressions for velocity, shear stress at the wall, pressure drop, and flow resistance are derived. The impact of different physical constants on the wall shear stress and impedance of the fluid is examined by numerical simulation. Streamline patterns of the nanofluid are investigated for different situations.

Keywords

  • stenosis
  • dilatation
  • couple stress fluid
  • impedance
  • shear stress

MSC 2010

  • 74F05
  • 76A05
  • 76Z05
  • 82D80
15 Articles
Open Access

A Numerical Examination of an Unsteady Nonlinear MHD Flow in the Presence of Thermal Radiation and Heat Generation

Published Online: 29 Jan 2021
Page range: 1 - 17

Abstract

Abstract

In this study, the spectral perturbation method and the spectral relaxation method are used to solve the nonlinear differential equations of an unsteady nonlinear MHD flow in the presence of thermal radiation and heat generation. The SPM is mainly based on series expansion, generating series approximation coupled with the Chebyshev spectral method. The numerical results generated using the spectral perturbation method were compared with those found in the literature, and the two results were in good agreement.

Keywords

  • unsteady MHD flow
  • spectral perturbation method
  • spectral relaxation method
  • thermal radiation
  • heat generation
Open Access

Initial Geometric Imperfections: A Robust, Closed-Section Cold-Formed Box Profile Application Subject to Local Buckling

Published Online: 29 Jan 2021
Page range: 18 - 44

Abstract

Abstract

Initial geometric imperfections are important for simulating local buckling in numerical models. References are found in the technical literature regarding open-section cold formed profiles. This work presents new procedures applied to a robust and closed-section cold formed profile subject to local buckling, and the use of procedures described in the technical literature already successfully used for open section profiles. The difference of this work in relation to the research already carried out is in the type of profile studied, in the mode of failure of the same and in the form of determination of the initial imperfections. The object of study of this work is a closed-section cold formed box profile with a short length when compared with its cross section and with local buckling failure mode. The strategies used in the present work to consider the initial geometric imperfections were to perform the linear stability analysis using the finite element method to obtain the local buckling mode that represents the deformed box profile geometry, to apply a multiplication factor in the displacements, replace the new geometry node coordinates for all profile nodes to induce the local buckling deformation mode, with model validation through experimental testing and the Effective Width Method (MLE) (ABNT NBR 14762 [1]). Finally, using the results of the collapse load of the experimental trial as a basis, it was possible to compare the results obtained by MLE and MEF. Thus, the presentation of this work used a methodology that describes the local buckling behavior and verified the precepts of the existing norms on the subject, combining theoretical and experimental methods, as they bring a better understanding of the structural problem in question.

Keywords

  • Bucket elevator
  • box profile
  • local buckling
  • finite element method
  • experimental test
  • initial geometric imperfections
Open Access

Computer Analysis of Dynamic Reliability of Some Concrete Beam Structure Exhibiting Random Damping

Published Online: 29 Jan 2021
Page range: 45 - 64

Abstract

Abstract

An efficiency of the generalized tenth order stochastic perturbation technique in determination of the basic probabilistic characteristics of up to the fourth order of dynamic response of Euler-Bernoulli beams with Gaussian uncertain damping is verified in this work. This is done on civil engineering application of a two-bay reinforced concrete beam using the Stochastic Finite Element Method implementation and its contrast with traditional Monte-Carlo simulation based Finite Element Method study and also with the semi-analytical probabilistic approach. The special purpose numerical implementation of the entire Stochastic perturbation-based Finite Element Method has been entirely programmed in computer algebra system MAPLE 2019 using Runge-Kutta-Fehlberg method. Further usage of the proposed technique to analyze stochastic reliability of the given structure subjected to dynamic oscillatory excitation is also included and discussed here because of a complete lack of the additional detailed demands in the current European designing codes.

Keywords

  • reliability analysis
  • Stochastic Finite Element Method
  • generalized stochastic perturbation technique
  • forced vibrations
  • Runge-Kutta-Fehlberg method
Open Access

Capture Efficiency of Magnetically Labeled Particles Traveling Through an Intracranial Aneurysm

Published Online: 29 Jan 2021
Page range: 65 - 75

Abstract

Abstract

Cell manipulation using external magnetic fields has been proposed to accelerate the neck reendothelization of saccular unruptured stented intracranial aneurysms. This work presents a computational fluid dynamics (CFD) model of a Saccular Brain Aneurysm that incorporates a helicoidal stent. An Eulerian-Lagrangian model implemented in ANSYS-Fluent is used to simulate the hemodynamics in the aneurysm. In silico studies have been conducted to describe the incidence of the magnetic field direction, frequency and amplitude on the blood hemodynamics and particle capture efficiency, when an external magnetic field is used to trap magnetically labeled particles traveling through the aneurysm. It is found that the magnetic field direction affects the particle concentration in the target region. Simulation results show that the highest particle capture efficiency is obtained with a 1T magnetic field amplitude in an open bore MRI scanner, when a permanent magnet is used.

Keywords

  • endothelization
  • particle manipulation
  • computational fluid dynamics
  • magnetohydrodynamics
Open Access

Reduced Differential Transform Method for Thermoelastic Problem in Hyperbolic Heat Conduction Domain

Published Online: 29 Jan 2021
Page range: 76 - 87

Abstract

Abstract

In the present study, we have applied the reduced differential transform method to solve the thermoelastic problem which reduces the computational efforts. In the study, the temperature distribution in a two-dimensional rectangular plate follows the hyperbolic law of heat conduction. We have obtained the generalized solution for thermoelastic field and temperature field by considering non-homogeneous boundary conditions in the x and y direction. Using this method one can obtain a solution in series form. The special case is considered to show the effectiveness of the present method. And also, the results are shown numerically and graphically. The study shows that this method provides an analytical approximate solution in very easy steps and requires little computational work.

Keywords

  • hyperbolic heat conduction
  • thermal stresses
  • thermal displacement
  • rectangular plate
  • reduced differential transform
Open Access

Exact Solutions for Fractionalized Second Grade Fluid Flows with Boundary Slip Effects

Published Online: 29 Jan 2021
Page range: 88 - 103

Abstract

Abstract

In this paper, an exact analytical solution for the motion of fractionalized second grade fluid flows moving over accelerating plate under the influence of slip has been obtained. A coupled system of partial differential equations representing the equation of motion has been re-written in terms of fractional derivatives form by using the Caputo fractional operator. The Discrete Laplace transform method has been employed for computing the expressions for the velocity field u(y, t) and the corresponding shear stress τ (y, t). The obtained solutions for the velocity field and the shear stress have been written in terms of Wright generalized hypergeometric function pψq and are expressed as a sum of the slip contribution and the corresponding no-slip contribution. In addition, the solutions for a fractionalized, ordinary second grade fluid and Newtonian fluid in the absence of slip effect have also been obtained as special case. Finally, the effect of different physical parameters has been demonstrated through graphical illustrations.

Keywords

  • second grade fluid
  • Caputo fractional operator
  • slip effects
  • discrete Laplace transform
Open Access

Hydrodynamic Analysis of Noise Propagation By the High Skew Marine Propeller Working in Non-Uniform Inflow

Published Online: 29 Jan 2021
Page range: 104 - 121

Abstract

Abstract

Being able to predict ship and marine propulsion noise is an important issue for naval architectures and the international maritime community. The main objective of this paper is the numerical investigation on the noise propagation by the high skew marine propeller working in a non-uniform inflow via RANS solver in the broadband frequency range. The pressure fluctuations were monitored at three points on the propeller blade, then by using the FFT operator we computed the blade passing frequency (BPF) for different propeller loading conditions. Based on these pressure pulses and adopting the Fowcs Williams-Hawking model we calculated noise radiated at the monitoring points. The results showed the BPF and noise level increased by increasing the load on the blades and we also observed that the noise generated at the leading edge was greater than at other points. Furthermore, the study of pressure fluctuations showed the propeller tip has more pressure variations in one revolution than other regions of the propeller surface.

Keywords

  • Noise
  • high skew marine propeller
  • pressure fluctuating
  • blade passing frequency
Open Access

Heat Transfer Effects on Free Convection of Viscous Dissipative Fluid Flow Over an Inclined Plate with Thermal Radiation in the Presence of Induced Magnetic Field

Published Online: 29 Jan 2021
Page range: 122 - 134

Abstract

Abstract

The principal objective of the present paper is to know the reaction of thermal radiation and the effects of magnetic fields on a viscous dissipative free convection fluid flow past an inclined infinite plate in the presence of an induced magnetic field. The Galerkin finite element technique is applied to solve the nonlinear coupled partial differential equations and effects of thermal radiation and other physical and flow parameters on velocity, induced magnetic field, along with temperature profiles are explained through graphs. It is noticed that as the thermal radiation increases velocity and temperature profiles decrease and the induced magnetic field profiles increases.

Keywords

  • thermal radiation
  • induced magnetic field
  • magnetic Prandtl number
  • free convection
  • Galerkin finite element method
  • viscous dissipation
Open Access

The Effect of Thermal Modulation on Double Diffusive Convection in the Presence of Applied Magnetic Field and Internal Heat Source

Published Online: 29 Jan 2021
Page range: 135 - 155

Abstract

Abstract

The investigation of thermal modulation on double-diffusive stationary convection in the presence of an applied magnetic field and internal heating is carried out. A weakly nonlinear stability analysis has been performed using the finite-amplitude Ginzburg-Landau model. This finite amplitude of convection is obtained at the third order of the system. The study considers three different forms of temperature modulations. OPM-out of phase modulation, LBMO-lower boundary modulation, IPM-in phase modulation. The finite-amplitude is a function of amplitude δT, frequency ω and the phase difference θ. The effects of δT and ω on heat/mass transports have been analyzed and depicted graphically. The study shows that heat/mass transports can be controlled effectively by thermal modulation. Further, it is found that the internal Rayleigh number Ri enhances heat transfer and reduces the mass transfer in the system.

Keywords

  • thermal modulation
  • weak nonlinear analysis
  • internal heating
  • Newtonian fluid
  • double diffusive convection
Open Access

The Onset of Soret Driven Ferrothermoconvective Instability in the Presence of Darcy Porous Medium with Anisotropy Effect and MFD Viscosity

Published Online: 29 Jan 2021
Page range: 156 - 177

Abstract

Abstract

The effect of magnetic field dependent (MFD) viscosity on Soret driven ferrothermohaline convection in a densely packed anisotropic porous medium has been studied. The Soret effect is focused on the system. A linear stability analysis is carried out using a normal mode technique and a perturbation method is applied. It is found that a stationary mode is favorable for the Darcy model. Vertical anisotropy tends to destabilize the system and the magnetization effect is found to stabilize the system. It is also found that the MFD viscosity delays the onset of convection. Numerical computations are made and illustrated graphically.

Keywords

  • anisotropy effect
  • Darcy model
  • MFD viscosity
  • porous medium
  • Soret coefficient
Open Access

Unified Methodology for Strength and Stress Analysis of Structural Concrete Members

Published Online: 29 Jan 2021
Page range: 178 - 200

Abstract

Abstract

In this paper, a methodology is presented for determining the stress and strain in structural concrete sections, also, for estimating the ultimate combination of axial forces and bending moments that produce failure. The structural concrete member may have a cross-section with an arbitrary configuration, the concrete region may consist of a set of subregions having different characteristics (i.e., different grades of concretes, or initially identical, but working with different stress-strain diagrams due to the effect of indirect reinforcement or the effect of confinement, etc.). This methodology is considering the tensile strain softening and tension stiffening of concrete in addition to the tension stiffening of steel bars due to the tensile resistance of the surrounding concrete layer. A comparison of experimental and numerical data indicates that the results, obtained based on this methodology, are highly reliable and highly informative.

Keywords

  • curvature
  • secant modulus
  • uniaxial stress-strain
  • extinction of prestressing
  • cracking
  • deformability
Open Access

Effect of Magnetic Field on Thermosolutal Instability of Rotating Ferromagnetic Fluid Under Varying Gravity Field

Published Online: 29 Jan 2021
Page range: 201 - 214

Abstract

Abstract

This paper deals with the theoretical investigation of the effect of a magnetic field, rotation and magnetization on a ferromagnetic fluid under varying gravity field. To find the exact solution for a ferromagnetic fluid layer contained between two free boundaries, we have used a linear stability analysis and normal mode analysis method. For the case of stationary convection, a stable solute gradient has a stabilizing effect, while rotation has a stabilizing effect if λ>0 and destabilizing effect if λ<0. Further, the magnetic field is discovered to have both a stabilizing and destabilizing effect for both λ>0 and λ<0. It is likewise discovered that magnetization has a stabilizing effect for both λ>0 and λ<0 in the absence of the stable solute gradient. Graphs have been plotted by giving numerical values of various parameters. In the absence of rotation, magnetic field and stable solute gradient, the principle of exchange of stabilities is found to hold true for certain conditions.

Keywords

  • thermosolutal instability
  • ferromagnetic fluid
  • rotation
  • magnetic field
  • magnetization
Open Access

Effects of Pressure Work Over a Semi-Infinite Vertical Oscillating Cylinder

Published Online: 29 Jan 2021
Page range: 215 - 225

Abstract

Abstract

An arithmetical methodology is used to study natural convection with properties of pressure work over a semi-infinite vertical oscillating cylinder. The governing partial differential equations are set up and the resulting equations are changed into a non-dimensional form using the proper non-dimensional quantities. The set of non-dimensional partial differential equations is solved arithmetically using a well-organized method known as the Crank-Nicolson method. The velocity, as well as temperature profiles for different values of parameters are studied with the assistance of graphs.

Keywords

  • cylinder
  • finite difference
  • pressure work
  • oscillating
  • skin friction
Open Access

Slowly Vibrating Axially Symmetric Bodies-Transverse Flow

Published Online: 29 Jan 2021
Page range: 226 - 250

Abstract

Abstract

Stokes drag on axially symmetric bodies vibrating slowly along the axis of symmetry placed under a uniform transverse flow of the Newtonian fluid is calculated. The axially symmetric bodies of revolution are considered with the condition of continuously turning tangent. The results of drag on sphere, spheroid, deformed sphere, egg-shaped body, cycloidal body, Cassini oval, and hypocycloidal body are found to be new. The numerical values of frictional drag on a slowly vibrating needle shaped body and flat circular disk are calculated as particular cases of deformed sphere.

Keywords

  • Stokes drag
  • axially symmetric bodies
  • Newtonian fluid
  • axial flow
Open Access

Effects of Stenosis and Dilatation on Flow of Blood Mixed with Suspended Nanoparticles: A Study Using Homotopy Technique

Published Online: 29 Jan 2021
Page range: 251 - 265

Abstract

Abstract

The paper deals with a theoretical study on blood flow in a stenosed segment of an artery, when blood is mixed with nano-particles. Blood is treated here as a couple stress fluid. Stenosis is known to impede blood flow and to be the cause of different cardiac diseases. Since the arterial wall is weakened due to arterial stenosis, it may lead to dilatation /aneurysm. The homotopy perturbation technique is employed to determine the solution to the problem for the case of mild stenosis. Analytical expressions for velocity, shear stress at the wall, pressure drop, and flow resistance are derived. The impact of different physical constants on the wall shear stress and impedance of the fluid is examined by numerical simulation. Streamline patterns of the nanofluid are investigated for different situations.

Keywords

  • stenosis
  • dilatation
  • couple stress fluid
  • impedance
  • shear stress

MSC 2010

  • 74F05
  • 76A05
  • 76Z05
  • 82D80

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