Waqar Khan

• PhD
• Professor at Prince Mohammad bin Fahd University

Articles you may be interested in Numerical solutions of mixed convection flow on a solid sphere embedded in a porous medium filled by a nanofluid containing gyrotactic microorganisms AIP Conf. Proc. 1522, 604 (2013); 10.1063/1.4801180 Marangoni convection flow and heat transfer in pseudoplastic non-newtonian nanofluids with radiation effects and h...

In this paper, for the first time the application of nanofluids is investigated from the point of view of thermoeconomics. For this purpose, the mixed convection flow of Al2O3-EG nanofluid in an isothermal vertical annulus is considered where three sets of models are used to calculate the viscosity and thermal conductivity of nanofluid. The main ai...

Flame stabilization is an important issue in practical applications of combustion systems. The bluff-body configuration is a common technique that stabilizes the flame by producing a strong recirculation zone downstream of the bluff body. Gas turbines provide a typical application of the bluff-body configuration. In this paper, a computational stud...

This study investigates the radiative, non-isothermal heat, and mass transfer in the stagnation point flow of Maxwell, micropolar, and Williamson nanofluids over a shrinking or stretching sheet embedded in a porous medium driven by buoyancy forces. The effects of suction or injection at the boundary, thermal radiation, and internal heat generation...

This study presents an innovative framework for modeling the liquid–vapor phase change interface in porous media by employing time-fractional derivatives. Traditional heat transfer models often rely on integer-order derivatives, assuming local and instantaneous diffusion processes, which fail to fully capture the memory effects and nonlocal dynamic...

The cone–disk system (CDS) involves a cone, which contacts a disk at its tip. This type of flow problem is used in some devices in medical sciences, such as viscosimeters and conical diffusers. The 3-D flow of a bio-nanofluid within the gap of a CDS is examined for the four selected arrangements: (i) rotating cone with stationary disk, (ii) rotatin...

This paper aims to design and evaluate a thermoelectric generation system optimized for low-to-medium temperature geothermal energy, focusing on maximizing power output and system efficiency. A one-dimensional mathematical model based on energy balance is employed for a single thermoelectric element and subsequently scaled to a 600 thermoelectric g...

This study investigates the role of time-fractional derivatives in the entropy analysis of mixed convection in a reacting nanofluid within a vertical permeable channel containing a Darcy-Forchheimer porous medium. This is crucial for enhancing heat and mass transfer, incorporating memory effects, and addressing delayed responses in various engineer...

This study presents a complete investigation of the chaotic fractional-order exothermic decomposition in a flow channel, concentrating on the interaction between reactant consumption and thermal dynamics. By employing a time-fractional derivative method, we originate and solve the system of differential equations along with boundary conditions, lea...

Effective thermal and flow control within complex geometries is essential for engineering applications. In this study, an in-depth examination of flow dynamics, entropy, and thermal regulation is undertaken within a square cavity featuring sinusoidal wall temperature. To introduce complexity, an inclined plate obstacle is strategically positioned w...

This study investigates the two-dimensional magnetohydrodynamic (MHD) boundary-layer flow over a stretching sheet embedded in a porous medium, focusing on the innovative use of hybrid nanofluids. The research has practical applications in heat exchangers, nanofluid technology, porous media, and MHD systems. Key governing parameters, including inter...

This work aims to investigate the unsteady hydromagnetic free convective flow of a viscous, electrically incompressible fluid influenced by an inclined magnetic field, radiation, and heat source. Specifically, it explores the behavior of water-based nanofluids under these conditions. The Newton-Raphson shooting technique combines the 4th-order Rung...

This paper presents a theoretical investigation of the inherent irreversibility in unsteady fractional time derivative mixed convection of a reacting nanofluid with heat and mass transfer mechanism over a slippery permeable plate embedded in a Darcy–Forchheimer porous medium. The model fractional partial differential equations are obtained based on...

This study investigates the flow of non-Newtonian Oldroyd-B and Jeffrey-Williamson ternary-hybrid nanofluids along a stretching sheet through a porous medium with a magnetic field. The nanofluid comprises titanium oxide, aluminum oxide, and silver dispersed in water. The effects of local thermal nonequilibrium conditions are also considered. The ma...

The mixed convective flow of Ree-Eyring ternary-hybrid nanofluids over a static wedge, incorporating the Cattaneo-Christov (C‐C) model was investigated to examine the fluid's heat and mass transfer characteristics. The novelty lies in using ternary-hybrid nanofluids comprising TiO₂, Al₂O₃, and Ag nanoparticles in wa...

The present paper proposes the mathematical model for non-Newtonian fluid (Ree-Eyring model) towards a stretched sheet with the porous medium by considering the gyrotactic microorganisms and the inclined magnetic field. The composite of Al₂O₃, Ag, and TiO₂ in water is called ternary-hybrid nanofluid (THNF), while th...

The primary focus of this study lies in exploring how thermal radiation and magnetic fields impact the flow of incompressible hybrid nanoparticles under combined convection within a concentric pipe containing porous media. The hybrid nanofluid, comprising H₂O as the base fluid and Ag and TiO₂ nanoparticles, takes center stage...

The present analysis signifies the impacts of fraction calculus on the MHD analysis of an incompressible fluid flow with entropy generation, viscous dissipation, and joule heating carried out between two endless vertical plates. The left vicinity of the MHD fluid flow channel has a convectively hot MHD fluid with a specific temperature that produce...

This study focuses on fractional order derivatives for the unsteady flow of MHD methanol-iron oxide nanofluid over a permeable vertical plate. The study incorporates fractional order derivatives to exhibit the system mathematically. The concluding model, which consists of the system of PDEs, has been solved via the Finite Difference Method, and gra...

How to precisely study the natural convection inside the curvilinear geometries with electrically conductive fluids and multidirectional magnetic fields is a vital problem in fluid mechanics. Herein, a numerical study is performed to examine the naturally magnetoconvective flow enclosed in a right-angled shaped trapezoidal cavity. The multidirectio...

This study investigates the mixed convection flow in a channel with a dimpled section and an adiabatic cylindrical obstacle under the influence of a magnetic field. The channel has a heated dimpled portion, while the flat horizontal walls are adiabatic. The energy equation considers the Joule heating effect, and the resulting momentum and thermal t...

This study investigates the radiative flow of rotating Sutterby magneto‐ternary hybrid nanofluids traveling along a stretchy surface in solar heating, ventilation, and air conditioning (HVAC). The investigation includes a colloidal mixture of three district types of particles, and impacts such as thermal radiative fluxing and activation energy. Thi...

This work explores the possessions of a condensed Sisko nanofluid’s MHD limit layer stream above a non-direct extended sheet, including the impact of liquefying heat move, synthetic response, thick dissemination, slip, and convective limit situation. Employing the shooting routine in conjunction with the Runge–Kutta-Fehlberg process, the intermedia...

The present theoretical investigation is conducted on a micropolar fluid medium channel in the presence of mixed and nonlinear convection with the assumptions of thermal radiation and species reactive agents. The nonlinear governing equations, which describe the micropolar fluid flow and energy, are converted into ordinary differential equations us...

University electronic learning (e-learning) has witnessed phenomenal growth, especially in 2020, due to the COVID-19 pandemic. This type of education is significant because it ensures that all students receive the required learning. The statistical evaluations are limited in providing good predictions of the university’s e-learning quality. That is...

This study aims to learn more about how the flow of a power-law nanofluid’s mixed bio-convective stagnation point flow approaching a stretchable surface behaves with the presence of a passively controlled boundary condition. The governing equations incorporate the motile bacterium and nanoparticles, and the current model includes Brownian motion an...

This study explores the impact of electronic payment systems on Saudi Arabia’s customer satisfaction during the COVID-19 pandemic. Descriptive analytical approach of a sample of 1,025 people living in Saudi Arabia was used to answer the study questions and test its hypotheses. Then, a new hybrid fuzzy inference system (HyFIS) is proposed to predict...

Solar air heaters convert clean solar energy into useable heat and thus have a wide range of applications. Computational fluid dynamics (CFD) can aid in the design and development of solar air heaters with optimized thermal efficiency. A detailed numerical study was conducted to investigate the fluid flow and heat transfer characteristics of a roug...

Saline water desalination is attaining a prime focus to meet the challenges of water scarcity in the developing countries. Solar energy could be effectively utilized for desalinating the saline/sea water. In this respect, humidification dehumidification (HDH) cycle could prove as a promising solar driven desalination technology. In this paper, exer...

Numerical simulation analyzes the mixed convection flow of Al2O3-Cu-H2O (aluminium oxide–copper–water) hybrid nanofluid inside a split lid-driven trapezoidal cavity. A triangular-shaped cold obstacle is placed inside the cavity. The horizontal base of the cavity is kept cold, whereas the side walls are chosen adiabatic. The thermally active upper w...

A comprehensive numerical study is presented for the hydromagnetic flow and heat transfer of Casson fluid in an enclosed partially heated triangular cavity. A cylindrical obstacle is placed with different thermal boundary conditions inside the cavity. The governing partial differential equations are converted to a non-dimensional form via suitable...

This analysis investigates the unsteady MHD free convection flow and heat transfer in an inclined U-shaped cavity filled with Cu-water nanofluid. Both the right and left walls of the cavity and the internal walls of the cavity are supposed to be adiabatic, while the upper horizontal walls of the cavity are kept at a lower temperature. A heat source...

In the previous decennium, considerable applications ofnanoparticles have been developed in the area of science. Nanoparticles with micropolar fluid suspended in conventional fluids can increase the heat transfer. Micropolar fluids have attracted much research attention because of their use in industrial processes. Exotic lubricants, liquid crystal...

In this numerical study, the effect of quartic autocatalysis type of chemical reaction, buoyancy force and thermal radiation phenomenon and magnetic effect on tangent hyperbolic nanofluid past an upper horizontal surface of a paraboloid has been studied. By considering the Buongiorno model approach, a diffusion of unequal coefficients in the presen...

The influence of thermal radiation and Joule heating on the entropy inception by triple diffusion over the permeable plate is examined, as well as its influence on other physical aspects of the problem. The radiative and Joules heating effects are being investigated using a mathematical model. The irreversibility caused variations in entropy incept...

This paper presents a novel idea of utilizing nanofluid as external cooling jacket around the condenser of an air conditioner. Experimental investigations were carried out to study the influence of two types of nanofluids namely, copper and aluminum oxide nanofluids on the performance of an air conditioner. The nanofluids were used to enhance the h...

A mathematical model is developed for viscous slip flow and heat transfer in water/Ethylene glycol‐based nanofluids containing metallic oxide nanoparticles, through a converging/diverging channel. We adopt the single‐phase Tiwari–Das model. The governing equations are transformed to a set of similarity differential equations with the help of simila...

The objectives of this study involve the optimization of longitudinal porous fins of square cross-section using metaheuristic algorithms. A generalized nonlinear ordinary differential equation is derived using Darcy and Fourier’s laws in the energy balance around a control volume and is solved numerically using RFK 45 method. The temperature of the...

Purpose This study aims to deal with the numerical investigation of ferrofluid flow and heat transfer inside a right-angle triangular cavity in the presence of a magnetic field. The vertical wall is partially heated, whereas other walls are kept cold. The effects of thermal radiation are included in the analysis. The governing equations including c...

Computational analysis of convective heat transfer characteristics of Al2O3–Cu-water hybrid nanofluid inside a triangular fin-shaped cavity is performed. A heater of different lengths is attached to the base wall while the other walls are kept cold. The governing equations are modeled and transformed into dimensionless forms by utilizing dimensionl...

Thermal and flow analysis is performed for natural convection in a porous trapezoidal cavity considering a non-equilibrium thermal energy transport model. The model study comprises a partially and fully heated bottom wall while obstacles are placed inside the cavity to examine the thermal behavior. However, governing energy and momentum equations e...

Analysis on natural convective heat transfer in different engineering systems allows optimizing the technical apparatus. For this purpose, numerical simulation of fluid flow and heat transport within the system is combined with entropy generation examination. The latter is very important considering the Gouy–Stodola theorem of thermodynamics. The p...

The objective of this research is to design, manufacture and test a multipurpose evaporative type cooler which can be employed for refrigeration as well as space cooling. The focus in this study has been on utilization of cooled water obtained during the air cooling process of desert cooler. The intended application for utilization of this cooled w...

In the present article, we investigate the dual slip effect namely the velocity slip and thermal slip conditions on MHD flow past a thin needle. The entropy generation for the incompressible fluids that’s water and acetone that flowing above the thin needle is discussed. The energy dissipating term and the magnetic effect is included in the axial d...

The present investigation aims to examine the heat flux mechanism in the hagnetohydro- dynamic (MHD) mixed convective flow of Williamson-type fluid across an exponential stretching porous curved surface. The significant role of thermal conductivity (variable), non-linear thermal radiation, unequal source-sink, and Joules heating is considered. The...

Entropy generation minimization approach is a very good method allowing to analyze the engineering systems to exclude technical failure. The present study deals with computational analysis of triple diffusive flow, energy transference and entropy production in different porous cavities from square to triangular through trapezoidal shape. The formul...

The present communication particularizes nonlinear convective non-Newtonian stagnation point flow and heat transference effects in stretchable flow of nanofluid. Magnetohydromagnetic steady viscous flow of nanofluid is examined. Heat transfer attributes of nanofluids are addressed via a numerical algorithm. Conductivity and diffusivity characterist...

In this article, we investigated entropy generation analysis for viscous fluid over a thin needle. Two types of viscous fluids namely air and water are considered as counter examples. The energy dissipating term is included in the axial direction. The Newtonian heating condition is considered on the needle boundary. The governing equations for the...

Purpose This study aims to investigate the irreversibility associated with the Fe3O4–Co/kerosene hybrid-nanofluid past a wedge with nonlinear radiation and heat source. Design/methodology/approach This study reports the numerical analysis of the hybrid nanofluid model under the implications of the heat source and magnetic field over a static and m...

In this work, a steady, incompressible Williamson fluid model is investigated in a porous wavy channel. This situation arises in the reabsorption of useful substances from the glomerular filtrate in the kidney. After 80% reabsorption, urine is left, which behaves like a thinning fluid. The laws of conservation of mass and momentum are used to model...

A computation analysis is performed to study double-diffusive natural convection in a right-angle trapezoidal cavity packed with a porous medium. The horizontal top and bottom boundaries are insulated and impermeable. The vertical left sidewall is kept at a constant heat flux and high concentration, whereas the inclined sidewall is held at lower te...

Current investigation scrutinizes the magnetohydrodynamic (MHD) natural convection flow of micropolar ferrofluid across an isoflux sphere with the impacts of thermal radiation and partial slip. Cobalt-nanoparticles with kerosene as the base fluid are considered. The governing partial differential conservation equations and convenient boundary condi...

In mathematical models, parameters are one of the most important input factors that affect the model outputs. In this work, the effects of parameters in complementing their interaction effects on nanofluids' output variables in converging and diverging channels have been studied. The mathematical model is solved numerically by using Matlab's built-...

The spread of the COVID-19 epidemic worldwide has led to investigations in various aspects, including the estimation of expected cases. As it helps in identifying the need to deal with cases caused by the pandemic. In this study, we have used artificial neural networks (ANNs) to predict the number of cases of COVID-19 in Brazil and Mexico in the up...

The study incorporates the time-dependent condensation model embedded in a porous medium with variations in liquid-vapor densities along with variable heat generation. A semi-implicit discretization is employed to convert the enthalpy based partial differential equations into a system of nonlinear algebraic equations. The dimensionless form of a tw...

The current investigation aims to explore the combined effects of heat and mass transfer on free convection of Sodium alginate-Fe3O4 based Brinkmann type nanofluid flow over a vertical rotating frame. The Tiwari and Das nanofluid model is employed to examine the effects of dimensionless numbers, including Grashof, Eckert, and Schmidt numbers and go...

In this study, the problem of carbon nanotubes (CNTs) suspended in water between two stretchable rotating disks is discussed. This problem is vital in the industry due to several applications, including the cooling of continuous filaments, drawing plastic films, and metal mining. The Darcy-Forchheimer scheme with convective boundary conditions, suc...

The steady heat and mass transfer problem of flow of an incompressible Newtonian fluid is investigated in this study. The axisymmetric flow of a non-isothermal and highly viscous fluid is considered through a narrow leaky tube of uniform cross-section with linear reabsorption across the wall. The Navier–Stokes equations are solved for axially symme...

This research is mainly concerned with the characteristics of magnetohydrodynamics and Darcy– Forchheimer medium in nanofluid flow between two horizontal plates. A uniformly induced magnetic impact is involved at the direction normal to the lower plate. Darcy–Forchheimer medium is considered between the plates that allow the flow along horizontal a...

In this study, we have proposed an artificial neural network (ANN) model to estimate and forecast the number of confirmed and recovered cases of COVID-19 in the upcoming days until September 17, 2020. The proposed model is based on the existing data (training data) published in the Saudi Arabia Coronavirus disease (COVID-19) situation—Demographics....

This article is devoted to studying Magnetohydrodynamic (MHD)'s combined effect and porosity on the entropy generation in two incompressible Newtonian fluids over a thin needle moving in a parallel stream. Two Newtonian fluids (air and water) are taken into consideration in this study. The viscous dissipation term is involved in the energy equation...

Carbon nanotubes (CNTs) are inevitable due to its tremendously high thermal and electrical conductivities, strength, stiffness, and toughness characteristics. The utilization of both porous media and nanofluids with CNTs as nanoparticles can augment the thermal efficiency of typical physical systems significantly. In view of such advantages, the pr...

The heat transfer phenomenon is beneficial and applicable in engineering, industries, and technological processes. The production of energy with the help of some cheap resources plays a pivotal and renewable role in the industrial development of the countries. Owing to such a significant performance of heat transfer, the steady slip flow and heat t...

The present work concentrates on two-dimensional unsteady incompressible flow of a micropolar cross nanofluid past a linear stretching/shrinking sheet with a magnetic field. The Cattaneo–Christov diffusion theory with heat and mass fluxes is incorporated into the study. Famous Buongiorno model featured by Brownian motion and thermophoresis accounti...

In the present study, an attempt is made to enhance the performance of heat pump by utilizing two types of nanofluids namely, copper and alumina nanofluids. These nanofluids were employed around the evaporator coil of the heat pump. The nanofluids were used to enhance the heat input to the system by means of providing an external jacket around the...

A boundary layer analysis of three dimensional electromagnetic flows of single and multi walls carbon nanotubes over the surface of a thin needle is addressed. Both single wall (SWCNTs) and multi wall (MWCNTs) are considered as nanoparticles whereas water is considered as base liquid. The energy equation is modeled by using non-linear thermal radia...

The thermal performance of an isothermal horizontal cylinder with different selected cross sections in cross-flow was investigated numerically. These cross sections include circular, elliptical, square, rectangular, hexagonal and triangular cross sections. The governing partial differential equations including continuity, momentum and energy equati...

The current research is conducted to investigate the slip effect and to analyze entropy production in both hybrid nanofluids, and common nanofluids flow past a convectively heated three-dimensional stretching sheet placed in a porous medium. The slip flow is considered in a Darcy-Forchheimer’s scheme by incorporating the nonlinear thermal radiation...

The constructal design-based model study is reported to numerically analyze the thermal control and heat augmentation inside a split lid-driven square cavity. A Y-shaped obstacle is placed inside the cavity and it is filled with Al2O3-Cu-water hybrid nanofluids. The concept of the split lid-driven cavity is utilized for the first time whereas the g...

The combined natural heat and mass transfer, the so-called thermosolutal convective problem, has become an attractive field of research in many diversified areas. In this paper, for the first time, entropy analysis has been carried out for triple diffusive flow. A comprehensive model is developed for the entropy generation due to fluid friction, po...

A CFD (computational fluid dynamics) analysis was carried out for the Bingham viscoplastic fluid flow simulations around cylinders of circular and square shapes. The governing equations in space were discretized with the finite element approach via a weak formulation and utilizing Ladyzhenskaya–Babuška–Brezzi-stable pair Q 2 / P 1 disc for approxim...

Mixed convection of nanofluid (a homogeneous mixture of water and single-walled carbon nanotubes) is investigated numerically in a triangular cavity containing an adiabatic pentagonal obstacle close to the top surface. Analytical models are employed for effective thermophysical properties of nanofluid regarding carbon nanotubes and water. The top w...

In this work, we identified the characteristics of unsteady magnetohydrodynamic (MHD) flow of ferrofluid past a radiated stretching surface. Cobalt–kerosene ferrofluid is considered and the impacts of Navier slip and convective heating are additionally considered. The mathematical model which describes the problem was built from some partial differ...

The purpose of the current study is to investigate the effects of water-based single-walled carbon nanotubes on free convection in a partially heated right trapezoidal cavity. The bottom wall of the cavity is heated while the side walls are kept cold, and the top wall is adiabatic. The governing dimensionless partial differential equations are solv...

Comprehensive reviews of rarefied gas flows in circular and square microchannels over wide ranges of rarefaction show large differences in Poiseuille numbers and reduced flow rates when identical length scales are used. The continuum Poiseuille numbers differ by 12.5%, and the free molecule reduced flow rates differ by 11%. This work demonstrates t...

Convective energy and mass transfer in various porous chambers are a wide-spread physical phenomenon in natural and technical systems. The triple diffusive free convection is examined in square, trapezoidal and triangular porous chambers under an impact of internal volumetric heat generation. The top and bottom surfaces of the chambers are assumed...

We have investigated the influence of hybrid nanoparticles on various physical quantities in a water-based hybrid nanofluid involved in a steady and fully developed forced convective flow generated over a stretched surface. Nonlinear thermal radiation and melting heat transfer analysis are featured in this work. To obtain the solution of the govern...

This work presents the effects of variable wall permeability on two-dimensional flow and heat transfer in a leaky narrow channel containing water-based nanoparticles. The nanofluid is absorbed through the walls with an exponential rate. This situation arises in reverse osmosis, ultrafiltration, and transpiration cooling in industry. The mathematica...

The flow and heat transfer in a trapezoidal cavity were investigated numerically. Water-based ferrofluid with Fe3O4 nanoparticles and porous medium with low Darcy number were chosen for the investigation. Both side walls were maintained at a constant cold temperature, the top wall was adiabatic, and the heater is placed at the bottom wall. The dime...

Recently, nanoparticles have supplied diverse challenges in the area of science. The nanoparticles suspended in several conventional fluids can convert the fluids flow and heat transmission features. In this investigation, the mathematical approach is utilized to explore the magnetohydrodynamics micropolar-nanofluid flow through a truncated porous...

A compact slip flow model is proposed for isothermal, incompressible gas flows in long microchannels of rectangular (square), trapezoidal (triangular), and double-trapezoidal (rhombic) cross sections in the slip flow regime. The model is based on superposition of the dimensionless mean continuum velocity and the dimensionless average slip velocity....

The present work is a computational investigation of nanofluid and hybrid nanofluid transport in a periodic structure. The governing equations for this work along with the appropriate boundary conditions are solved using the finite-volume method. The simulations are carried out using five wavy amplitudes of the channel shape for a range of Reynolds...