Jafar Ghazanfarian

University of Zanjan · Department of Mechanical Engineering

Flow over an oscillating cylinder has been the subject of various studies as well as its heat transfer characteristics due to the lock-in phenomenon which occurs as a result of multiple frequencies being present in the system. The motivation was to investigate the effect of superhydrophobicity on heat transfer and wake dynamics of partially superhy...

The accuracy of the classical heat conduction model, known as Fourier's law, is highly questioned, dealing with the micro and nanosystems and biological tissues. In other words, the results obtained from the classical equations deviate from the available experimental data. It means that the continuum heat diffusion equation is insufficient and inap...

Numerical simulation of convective heat transfer over a stationary and transversely oscillating partial super-hydrophobic cylinder has been performed using OpenFOAM libraries. Superhydrophobicity of the cylinder surface has been addressed by means of a partial slip boundary condition. Applying the slip condition to the surface of the stationary cyl...

In this paper, the pore network model to investigate the reaction-diffusion process in the hierarchically structured porous catalyst particle is extended to consider the phenomenon of deactivation by coking. In this framework, the interaction of internal particle pore structure and mass transfer under the condition of coke deposition are examined....

In the last decade, an enormous amount of attention has been paid to piezoelectric harvesters due to their flexibility in design and the increasing need for small-scale energy generation. As a result, various energy review papers have been presented by many researchers to cover different aspects of piezoelectric-based energy harvesting, including p...

One of challenging issues in design of extended surfaces based on radial fins is increment of the drag force as well as reduction of the convection power due to creation of dead regions inside cavities. This drawback has made the use of this type of extended surfaces not common in the industry. In this article, we have investigated thermal/flow cha...

In heat transfer augmenting methods such as radial fins, the heat transfer enhancement commonly leads to the drag force increment. In the present paper, slots are inserted over the fins to simultaneously reduce the drag coefficient. Turbulent convection heat transfer around a cylinder, as well as oscillating bundle of tubes including the slotted ra...

In heat transfer augmenting methods such as radial fins, the heat transfer enhancement commonly leads to the drag force increment. In the present paper, slots are inserted over the fins to simultaneously reduce the drag coefficient. Turbulent convection heat transfer around a cylinder, as well as oscillating bundle of tubes including the slotted ra...

The accuracy of the classical heat conduction model, known as Fourier's law, is highly questioned, dealing with the micro/nanosystems and biological tissues. In other words, the results obtained from the classical equations deviates from the available experimental data. It means that the continuum heat diffusion equation is insufficient and inappro...

Different permutations of the single and the twofold dam break flow have been investigated using the mesh-free smoothed-particle hydrodynamics and the experimental setup.The free-surface deformation in the case with the wet bed for five different downstream water heights has been investigated and respective numerical and experimental results were p...

In the last decade, an explosive attention has been paid to piezoelectric harvesters due to their flexility in design and increasing need to small-scale energy generation. As a result, many review papers have been presented by many researchers to cover different aspects of piezo-based energy harvesting, including piezomaterials, modeling approaches...

The non-Fourier dual-phase-lag heat model has been solved as a well-known accurate bioheat model to compute the temperature distribution in a three-dimensional multi-layered skin of the human finger including the embedded vessels. A novel conjugate solver over the platform of OpenFOAM codes has been developed. Three types of vessels that are repres...

Impacts of the laminar airflow ventilation system design factors on contaminant removal and thermal comfort condition in an operating room have been investigated by means of Lagrangian-based particle transport using the non-Boussinesq modeling of the buoyancy effects. An operating room including staffs and a patient with realistic human geometries...

The reaction-diffusion process in the hierarchically structured porous catalyst particle is investigated using the pore network model. A self-developed scheme is presented to generate the hierarchical pore network with a fairly low computational cost. The results were presented in the framework of a parametric sweep o f the macroporosity, the nanop...

Results of the large eddy simulations (LES) over two partially superhyrophobic 3D geometries, including the backward-facing step and the sphere at the Reynolds number of 400, 1000, 2000 have been presented using the open-source OpenFOAM C++ libraries. The effect of imposing the locally partial-slip on the surface of the mentioned cases has been inv...

Numerical analysis of heat transfer from heated oscillating tube bank in cross flow has been investigated for aligned array of tubes using the opensource field operation and manipulation (OpenFOAM) C++ library. The heat exchanger constructed based on the present idea of tube oscillation is called the oscillating heat exchanger (OHE). The verificati...

The ”sliding-wall concept” has been introduced for the case of convective heat transfer past a square cylinder with an angle of incidence. Based on this concept, all walls of the cylinder tangentially move at a constant speed. This idea is denominated the ”sliding-wall concept”, which can be constructed using a strip that is rolled around the body...

Three-dimensional numerical simulations of turbulent ow over a partial super-hydrophobic cylinder, hereinafter referred to as the \Janus cylinder", are performed using large-eddy simulation (LES) with OpenFOAM solver. The slip-wall velocity at the super-hydrophobic surface is evaluated from a third-type (Robin) boundary condition whose coefficient...

Numerical and experimental investigations were conducted to find the effect of percentage and distribution of porosity and heat treatment on the conductivity coefficient value in plasmasprayed thermal barrier coatings (TBC). The numerical analysis of the SEM images of six plasma-sprayed samples showed an explicit relation between changes in the por...

The numerical simulation of non-Fourier dual-phase-lag heat conduction in three-dimensional bio and nano media has been investigated with two developed solvers using the OpenFOAM C++ finite-volume libraries. Despite the rapid growth in the use of non-Fourier heat transfer model, most researchers conduct simulations over simple geometries due to num...

This paper studies multi-dimensional free-surface problem using a hybrid method combining the particle-based Smoothed-Particle Hydrodynamics (SPH) and atomistic Molecular dynamics (MD) techniques. In order to verify/validate the accuracy of the numerical solver, several cases including the 2D single-phase and two-phase dam break flows with dry bed,...

In this chapter we are to develop the idea of using online virtual reality (OVR) or online augmented reality (OAR) concepts for redesigning academic laboratory equipment or any kind of virtual classes to enhance the efficiency of learning process. One of the main advantages of OVR is the interactions of students with each other from different locat...

The two dimensional and three dimensional numerical simulation of blood flow in a centrifugal pump with 16 radial blades placed on a magnetically suspended impeller have been presented. The results of simulation for the pump of model Kyoto-NTN have been obtained using multi-reference frame (MRF), sliding mesh, and dynamic mesh methods. With the ass...

جریان‌های چگال یا گرانشی، جریان‌هایی هستند که در آن‌ها اختلاف چگالی سیال ورودی با سیال محیط موجب توسعه جریان می‌شود. اختلاف چگالی می‌تواند ناشی از اختلاف دما، غلظت و یا حضور ذرات معلق باشد. در مقاله حاضر هدف بررسی تأثیر حضور مانع به شکل مکعب روی رفتار جریان و نیز تغییرات سرعت و تغییر قطر ذرات می‌باشد. بدین منظور شبیه‌سازی به روش گردابه‌های بزرگ (LE...

Due to the importance of the transistors in nano-electronics technology, the accurate study of these nano-devices is an essential field of research. Taking into account the non-Fourier nature of heat transfer with considering the three-dimensional structure of the silicon nano-devices, are the challenges in transistor analysis which have not been s...

Due to the importance of the transistors in nano-electronics technology, the accurate study of these nano-devices is an essential field of research. Taking into account the non-Fourier nature of heat transfer with considering the three-dimensional structure of the silicon nano-devices, are the challenges in transistor analysis which have not been s...

The drag suppression for a high-amplitude oscillating cylinder is simulated using various configurations of detached-splitter plates. Governing parameters are the length of splitters (L), the cylinder–splitter gap (G), the amplitude (A), and the frequency of oscillation (f0). The control-volume technique along with the ACMI (arbitrary coupled mesh...

This paper studies a two-dimensional incompressible viscous flow past a circular cylinder with in-line oscillation close to a free-surface. The sub-particle scale (SPS) turbulence model of a Lagrangian particle-based smoothed-particle hydrodynamics (SPH) method has been used to solve the full Navier-Stokes equations together with the continuity equ...

This article presents the thermal transport across solid-gas interface in micro/nano-channels in microelectronic devices and illustrates the nanoscale thermal resistance using thermal lattice Boltzmann method. The partial equilibrium between the gas molecules and phonons at the interface is implemented for the conjugate heat transfer simulation. Th...

This paper studies the two-dimensional (2D) water-entry and exit of a rotating circular cylinder using the Sub-Particle Scale (SPS) turbulence model of a Lagrangian particle-based Smoothed-Particle Hydrodynamics (SPH) method. The full Navier-Stokes (NS) equations along with the continuity have been solved as the governing equations of the problem....

The classical model of the Fourier’s law is known as the most common constitutive relation for thermal transport in various engineering materials. Although the Fourier’s law has been widely used in a variety of engineering application areas, there are many exceptional applications in which the Fourier’s law is questionable. This paper gathers toget...

Non-linear Pennes’ bioheat equation including the thermal wave model of bioheat transfer as well as the dual-phase-lag model has been discretized using a mesh-free Smoothed-Particle Hydrodynamics (SPH) procedure. The time evolution of the temperature distribution within a living tissue and effect of non-linearity in the PDEs on the solution have be...

This paper proposes a newly developed smoothed-particle hydrodynamics (SPH) method for the solution of one-dimensional heat conduction problem within a nanoscale thin slab for Knudsen numbers of 0.1 and 1 under the effect of dual-phase-lag (DPL) model. A novel temperature-jump boundary condition is applied to the Lagrangian particle-based mesh-free...

This article presents a numerical investigation of 2D turbulent flow within a double external gear pump. The configuration of the inlet and outlet ports is determined such that the double gear pump acts like the combination of two parallel pumps. The complex geometry of the double gear pump, existence of narrow gaps between rotating and stationary...

This paper studies the two-dimensional water-entry and exit of a rotating circular cylinder using the Sub-Particle Scale (SPS) turbulence model of a Lagrangian particle-based Smoothed-Particle Hydrodynamics (SPH) method. The full Navier-Stokes equations along with the continuity have been solved as the governing equations of the problem. The accura...

This paper uses the finite volume lattice Boltzmann method (FVLBM) to simulate the transient heat conduction from macro- to nano-scales corresponding to Kn = 0.01-10. This model is used for two dimensional (2D) transient hotspot modeling. The results of the diffusive regime are compared with those of the Fourier law as a model of continuum mechanic...

This paper investigates electro-thermal aspects of high-k material as well as SOI technology in the nano-scale n-MOSFET by the numerical simulation of dual-phase-lag (DPL) heat conduction model under the effect of self-heating phenomenon. Three types of MOS devices including bulk, SOI, and high-k MOSFETs are considered. All of the electro-thermal p...

The one-dimensional non-linear non-Fourier heat conduction within a thin film of solid argon is numerically investigated under the framework of the Dual-Phase-Lagging (DPL) model with the boundary phonon scattering. Considering temperature-dependent thermal properties for solid argon, the results are compared with those obtained from the Molecular-...

This paper studies the two-dimensional water-entry and sedimentation of an elliptic cylinder using the Sub-Particle Scale (SPS) turbulence model of a Lagrangian particle- based Smoothed-Particle Hydrodynamics (SPH) method. The motion of the body is driven by the hydrodynamic forces and the gravity. The present study shows the ability of the SPH met...

This paper studies the two-dimensional water-entry and sedimentation of an elliptic cylinder using the subparticle scale (SPS) turbulence model of a Lagrangian particle-based smoothed-particle hydrodynamics (SPH) method. The motion of the body is driven by the hydrodynamic forces and the gravity. The present study shows the ability of the SPH metho...

The thermal performance of two-dimensional (2D) field-effect transistors (FET) is investigated frequently by solving the Fourier heat diffusion law and the Boltzmann transport equation (BTE). With the introduction of the new generation of 3D FETs in which their thickness is less than the phonon mean-free-path it is necessary to carefully simulate t...

This paper studies the two dimensional simulation of water impact and sedimentation of circular and elliptic bodies in a Newtonian incompressible fluid using particle-based SPH (Smoothed Particle Hydrodynamics) method. The motion of the body is driven by the hydrodynamical forces and gravity. The present study shows the ability of SPH method in the...

This paper investigates the numerical simulation of non-Fourier transient heat transfer in a two-dimensional sub-100 nm metal-oxide-semiconductor field-effect transistor (MOSFET). The dual-phase-lag (DPL) model with a specific normalization procedure is introduced for the modeling of nanoscale heat transport. The boundary conditions are selected si...

Analytical and numerical solutions of the 2D transient dual-phase-lag (DPL) heat conduction equation are presented in this article. The geometry is that of a simplified metal oxide semiconductor field effect transistor with a heater placed on it. A temperature jump boundary condition is used on all boundaries in order to consider boundary phonon sc...

In this reply to the Comment by Li-Shi Luo, we discuss the results of the lattice Bhatnagar-Gross-Krook (LBGK) model for high-Knudsen-number (Kn) flow and heat transfer, in the range of Kn⩽1. We present various studies employing the LBGK model for high-Kn flow and heat transfer simulations. It is concluded that, with the use of the LBGK model in th...

This article presents two dimensional investigation of laminar �ow past a square cylinder with incident angle and moving walls in order to suppress drag and generate lift coefficient. Two incident angles of 0 and 45 are considered. Dimensionless velocity magnitudes of v= 0, 1 , 2, and 3 are imposed at the cylinder walls. haracteristic based splitti...

In this study convective heat transfer from a rotating cylinder with inline oscillation is studied using a finite element method based on the Characteristic Based Split method (CBS) to solve governing equations consisting of continuity, full Navier–Stokes, and energy equations. Employing the Arbitrary Lagrangian-Eulerian (ALE) formulation, the dyna...

The present paper deals with the two-dimensional numerical simulation of gaseous flow and heat transfer in planar microchannel and nanochannel with different wall temperatures in transitional regime 0.1≤Kn≤1 . An atomistic molecular simulation method is used known as thermal lattice-Boltzmann method. The results of simulation are presented in four...

In this paper various methods used for ventilation of operating room and optimized air conditioning systems are investigated. 3-D viscous fluid flow is simulated numerically in order to model and compare different modern ventilation methods. Generally two common methods exist for ventilation of operating room called laminar flow and turbulent flow...

In this paper, one dimensional heat conduction within a thin slab for Knudsen numbers more than 0.1 is simulated using Dual-Phase-Lag (DPL) model including phonon scattering boundary condition. The Dual-phase-lag equation is solved with a stable and convergent finite difference scheme. Also the Laplace transformation technique is employed to solve...

This paper studies a two-dimensional incompressible viscous flow past a rotating cylinder with cross flow oscillation using a finite element method based on the characteristic based split (CBS) algorithm to solve governing equations including full Navier–Stokes and continuity equations. Dynamic unstructured triangular grid is used employing lineal...

This article presents a numerical investigation of convective heat transfer from a rotating cylinder with cross-flow oscillation. A finite element analysis using Characteristic Based Split method (CBS) is developed to solve governing equations involving continuity, Navier–Stokes, and energy equations. Dynamic unstructured triangular grid is used em...

In this paper, one-dimensional heat conduction within a thin slab for Knudsen numbers more than 0.1 is implemented using the Dual-Phase-Lag (DPL) model including phonon scattering boundary condition. The Dual-Phase-Lag equation is solved with a stable and convergent finite difference scheme. Also the Laplace transformation technique is employed to...

This article presents a two-dimensional finite difference numerical model of steady laminar mixed convection inside a square vented cavity filled with a fluid-saturated porous medium for different outlet port positions. It was assumed that one of the vertical walls is at constant temperature, while the remaining walls are perfectly insulated (adiab...

One dimensional problem of heat conduction for the Knudsen numbers more than 0.1 corresponding to nano-structures is implemented utilizing the Dual-Phase-Lag (DPL) model and its special case, Cattaneo and Vernotte (CV) model as well as the Fourier law. The results are compared with the results obtained from the Ballistic-Diffusive Equations (BDE) m...