Momentum Boundary Layer Research Articles

Numerical study of blood-based MHD tangent hyperbolic hybrid nanofluid flow over a permeable stretching sheet with variable thermal conductivity and cross-diffusion

Abstract Modern heat transport processes such as fuel cells, hybrid engines, microelectronics, refrigerators, heat exchangers, grinding, coolers, machining, and pharmaceutical operations may benefit from the unique properties of nanoliquids. By considering Al 2 O 3 {{\rm{Al}}}_{2}{{\rm{O}}}_{3} nanoparticles as a solo model and Al 2 O 3 – Cu {{\rm{Al}}}_{2}{{\rm{O}}}_{3}{\rm{\mbox{--}}}{\rm{Cu}} as hybrid nanocomposites in a hyperbolic tangent fluid, numerical simulations for heat and mass transfer have been established. To compare the thermal acts of the nanofluid and hybrid nanofluid, bvp4c computes the solution for the created mathematical equations with the help of MATLAB software. The impacts of thermal radiation, such as altering thermal conductivity and cross-diffusion, as well as flow and thermal facts, including a stretchy surface with hydromagnetic, and Joule heating, were also included. Furthermore, the hybrid nanofluid generates heat faster than a nanofluid. The temperature and concentration profiles increase with the Dufour and the Soret numbers, respectively. The upsurge permeability and Weissenberg parameter decline to the velocity. An upsurge variable of the thermal conductivity grows to the temperature profile. Compared to the nanofluids, the hybrid nanofluids have higher thermal efficiency, making them a more effective working fluid. The magnetic field strength significantly reduces the movement and has a striking effect on the width of the momentum boundary layer.

Soret and Dufour effects on an unsteady MHD flow about a permeable rotating vertical cone with variable fluid properties

The objective of the present work is to examine the characteristics of unsteady incompressible magnetohydrodynamic fluid flow around a permeable rotating vertical cone. The effects of thermal radiation, viscous dissipation, and the Soret and Dufour effects are investigated in the analysis of heat and mass transfer. The viscosity of the fluid is considered inversely proportional to the temperature, and the thermal conductivity of the fluid is considered directly proportional to the temper-ature. The governing equations are converted into ordinary differential equations using suitable similarity transformations, which are then solved numerically using bvp4c from MATLAB. Results obtained in this study are in excellent correlation with previously conducted studies. The results demonstrate that the Dufour and Soret effects subsequently reduce the heat transit rate (by –3.3%) and mass transit rate (by –1.2%) of the system. It is also detected that fluids with higher viscosity tend to increase tangential skin friction (+8.9%) and azimuthal skin friction (+8.3%). The heat transit rate of the system is found to be more efficient for fluids with higher viscosity and lower thermal conductivity and Eckert numbers. Further-more, the thickness of the momentum, thermal, and concentration boundary layers significantly reduces while the heat and mass transit rates (+17.8% and +18.3%, respectively) of the system become more efficient for greater values of the un-steadiness parameter.

Radiation-influenced magnetohydrodynamic third-grade nanofluid flow around non-linearly stretched cylinder

Abstract This analysis considers the magnetized third-grade fluid stream and microorganisms over a non-linear stretchy cylinder. The radiation impacts are taken into consideration. The effects of the governing flow at the cylinder are represented in the form of PDEs employing boundary layer approximations. The system of the PDEs is further reduced in dimensionless form after applying the similarity transformations. The dimensionless system of non-linear ODEs is solved through the numerical technique bvp4c. The effects of radiation and magnetism on the third-grade liquid over a non-linear extending cylinder are highlighted in graphs and numerically in tabular form. The influence of fluid variables on the velocity curve, such as third-grade parameters, second-grade coefficients, and Reynolds number, is illustrated and explored. Suitable ranges for the parameters $( {1 \le \eta \le 10,\ 0.2 \le {{\alpha }_1} \le 0.5,\ 0 \le {{\alpha }_1} \le 1.5,\ 0.1 \le \beta \le 0.3,\ 0.1 \le \gamma \le 1.6,\ 0.05 \le M \le 0.15,\ 0.5 \le \delta \le 2.0,\ 0.7 \le Pr \le 1.3,\ 0.1 \le Rd \le 0.4,0.1 \le}$ ${e \le 0.4} )$ are chosen depending upon the convergence of the numerical method. The widths of the velocity and momentum boundary layers are revealed to be increasing functions of the curvature parameter. The temperature curve declines when boosting third-grade parameters, thermal stratification, and Hartmann number while boosting up for curvature and radiation parameters.

Viscous dissipation and Joule heating effects of Carreau nanofluid axisymmetric flow past unsteady radially stretching porous disk

In this piece of communication, a theoretical investigation of two dimensional boundary layer flow of Magnetohydrodynamics (MHD) Carreau nanofluid axisymmetric flow past unsteady radially stretching porous disk is made. The investigation includes the effects of viscous dissipation, Joule heating, thermal radiation, suction/injection, Darcy–Forchheimer porosity model and binary chemical reaction with activation energy, etc. To examine the impacts of the aforementioned effects, the conservation laws are formulated with strongly nonlinear partial differential equations (PDEs), which are then transformed into a system of initial value problems (IVPs) using appropriate similarity transformations and techniques. The 5th order Runge–Kutta with the shooting technique is used to find numerical solutions aided by Python programming with built in program “fsolve”. The method is validated with other published articles under common assumptions and it agrees nicely. The impacts of the pertinent parameters on velocity, temperature, concentration, skin friction coefficient and the rates of mass and heat transfers with in the flow regime are displayed using graphs and tables. The main outcomes include the motivation of local Nusselt and Sherwood numbers for shear thickening (n=1.5) than shear thinning (n=0.5) cases of the Carreau nanofluid. The momentum boundary layer of the Carreau nanofluid gets thinner with an increase in Forchheimer number, unsteady and suction parameters. A dual nature is observed for concentration of the Carreau nanofluid with a rise in Eckert number, i.e increasing in concentration around the wall and decreasing far away from the wall. The rise in destructive and constructive chemical reaction parameters disperse and accumulate the concentration of the system, respectively.

The use of neural computational analysis for drug delivery applications results in hybrid nanofluid flow between the uniform gap of two concentric tubes

The blood-based Ag and TiO2 Hybrid nanofluids (HNFs) flow between the two tubes are used for drug delivery applications. Ag and TiO2 hybrid nanofluids have immense potential as drug delivery agents due to their unique properties, controlled release capabilities, targeting abilities, and synergistic effects. Extensive research is being conducted to optimize their design and maximize their effectiveness in various therapeutic applications using experimental approaches. The recent work has been focused on theoretical analysis using the existing experimental data. These HNFs are functionalized with ligands or antibodies to specifically target and deliver drugs to diseased tissues or cells. This targeted approach enhances drug accumulation at the desired site, minimizing systemic toxicity and improving treatment outcomes. An external magnetic field is applied to control the release of drugs from the nanofluids. Magnetic nanoparticles such as iron oxide nanoparticles are incorporated into the nanofluids, which respond to the magnetic field and release the drug at a specific location and time. This offers a controlled and targeted drug delivery system. The graphical and numerical outcomes of the dimensionless momentum and thermal boundary layers are investigated and discussed. It is observed that hybrid nanofluids (HNFs) often exhibit superior heat transfer (HT) properties, primarily due to the high thermal conductivity of nanoparticles. Improving heat transfer helps reduce skin friction by maintaining a more uniform temperature distribution near the surface. Also, this acts in the optimization of the blood flow analysis. In terms of drug delivery applications, hybrid nanofluids are more prominent in refining applications through optimized heat transfer, as shown by the comparison.

Magnetized heat transfer visualization through computational modeling of third-grade fluid via exponentially stretching cylinder

The steady MHD boundary-layer axis-symmetric flow of a third-grade fluid passing through an exponentially expanded cylinder in the vicinity of a magnetic field is investigated in this study. The problem is mathematically modeled. Suitable similarity transformations are carried out to convert the partial differential equations into nonlinear ordinary differential equations. The Runge–Kutta fourth-order shooting technique is used to solve the transmuted system of nonlinear ODEs. Graphical representations of numerical findings are used to examine the effects of various physical factors on the velocity and temperature profiles. The influence of fluid variables on the velocity curve, such as third-grade parameters, second-grade parameters, and Reynolds number, is illustrated and explored. The skin-friction coefficient expression is computed and given. The widths of the velocity and momentum boundary layers are revealed to be increasing functions of the curvature parameter. It is found that the third-grade fluid has a higher velocity profile than Newtonian and second-grade fluids. Also, the stretched cylinders cause a more progressive shift in heat and mass pattern for flow than flat plates do.

Numerically analyzed of ternary hybrid nanofluids flow of heat and mass transfer subject to various shapes and size factors in two-dimensional rotating porous channel

This article examines the behavior of (Cu–Al2O3–TiO2) nanoparticles with varying shapes and sizes regarding their flow and thermal performance. A ternary hybrid MHD model is developed to study rotating porous walls associated with permeable Reynolds numbers and NPs for a specific range of the volume friction φ1,φ2 and φ3 (2%–10%). Considering morphology effects, the expanding/contracting phenomenon for heat and mass transfer enhancement is presented. Non-linear differential equations are derived from governing PDES and solved using the shooting procedure. The study aims to analyze the improvement in parameters such as stretching ratio parameter (α), nanoparticles volumetric fractions (φ1,φ2,φ3), magnetic parameter (M), Prandtl number (Pr) permeable Reynold number (Re), (Kcr) chemical reaction parameter, Schmidt number (Sc), and rotational parameter (R0) with ternary hybrid nanofluid (Cu–Al2O3–TiO2/water). The impacts of these parameters on the temperature profiles of different shapes of nanoparticles, such as spherical, brick, cylinders, and platelets, are also analyzed. The influences of these parameters (α), (φ1,φ2, φ3), (M), (Pr), (Re), (Kcr) (Sc) and (R0) impacts on skin friction coefficient, Nusselt number, and Sherwood number for different shapes and sizes of nanoparticles are discussed. The study suggests that platelet-shaped nanoparticles are more appropriate for non-dimensional physical parameters. Boosting Re, M, and R enlarges momentum boundary layers and enhances the radial velocity profile. Expanding the expansion ratio and volume of friction parameters influences heat transfer rates oppositely on the temperature profile. Elevating the Schmidt number diminishes the mass transfer rate in the upper boundary layer thickness but amplifies it in the lower boundary one in the concentration profile.

Neural network and thermodynamic optimization of magnetized hybrid nanofluid dissipative radiative convective flow with energy activation

This article, motivated by hybrid magnetic coating manufacturing developments, utilizes a neural network-based computational program to study the dynamics of hybrid magnetic nanofluids with entropy generation. A new physico-chemo-mathematical model has been presented to simulate the hybrid magnetic nano-coating flow along a stretching surface to a porous medium with viscous heating. A Rosseland flux model is used for radiation heat transfer and Darcy’s model for the isotropic porous medium. The stretching sheet is porous, and wall suction or injection are possible. A robust neural network has been deployed to optimize the physical parameters controlling the transport characteristics of hybrid nanofluids. Specifically, two hybrid nanoparticle combinations are addressed, namely graphite oxide (GO)-molybdenum disulfide ( Mo S 2 ) and copper (Cu)-silicon dioxide ( Si O 2 ), both with engine oil as the base fluid. The dimensional boundary layer model is transformed via suitable scaling variables from a partial differential system into a dimensionless non-linear coupled ordinary differential system. The transformed boundary value problem is solved numerically with the BVP4C subroutine in the symbolic software MATLAB, which achieves exceptional accuracy. Validation with previous simpler studies is conducted and a good correlation is obtained. The neural network optimization analysis incorporates Bayesian regularization as the training algorithm. The Bejan entropy generation minimization (EGM) analysis shows that with increasing radiation parameter R d , both entropy generation rate and Bejan number are increased. Furthermore, an elevation in Brinkman number Br leads to an upsurge in entropy generation rate and a downtrend in the Bejan number. The numerical solution of the boundary value problem reveals that with an increment in nanoparticle solid volume fraction φ 2 , magnetic parameter M , inverse permeability parameter ϵ , surface injection parameter ( s < 0 ) , Eckert number Ec and radiation parameter R d and with a decrement in suction parameter ( s > 0 ) and Prandtl number Pr , there is a strong enhancement in temperature magnitude and thermal boundary layer thickness. With greater nanoparticle solid volume fraction φ 2 , magnetic parameter M , inverse permeability parameter ϵ , suction parameter s and a reduction in thermal buoyancy parameter λ , strong flow deceleration is induced, and momentum boundary layer thickness is increased. The skin friction coefficient is substantially boosted with lower values of magnetic parameter M , inverse permeability parameter ϵ , suction parameter s and higher values of thermal buoyancy parameter λ . There is a significant decrement also computed in Nusselt number with a greater radiation parameter R d . The simulations provide a good benchmark for future extensions that may consider non-Newtonian behavior.

Chemical reaction, slip effects and non-linear thermal radiation on unsteady MHD Jeffreys nanofluid flow over a stretching sheet

“The boundary layer flow past the stretching surface by the velocity slip and the temperature jumping boundary situations is the imperative type of the flow and temperature transports happening in a number of engineering and industrial applications. Keeping in this mind, the magnetohydrodynamic (MHD) flow and temperature transport of the Jeffreys nanoliquid past a stretching sheet by the non-uniform temperature source and/or sink is explored in the current investigation. The governing scheme of the partial differential equations represents the prescribed problem and is condensed into the non-linear ordinary differential equations with the help of similarity transformations. The revised non-dimensional equations are solved computationally making use of the Runge-Kutta-Fehlberg 45 order method and the shooting method. The results are comparing by the published work for some limiting cases and they are examined to the outstanding agreements. The impacts of all flow significant parameters are traced in terms of the tables and graphical profiles. This is established that, both initial and second order velocity slip parameters trim downs the thickness of momentum boundary layers and therefore decreases the velocity as a results of these one might found the increases in the thermal boundary layer.” The boundary layer thickness and the fluid velocity increases with increase in Deborah number.

Triple diffusive free magneto-convection of electro-conductive nanofluid from a vertical stretching sheet

In the present investigation, an analysis is carried out to study the MHD triple diffusive free thermo-solutal convection boundary layer flow of an electro-conductive nanofluid flow over a vertical stretching sheet. This problem is relevant to magnetic nanomaterials fabrication operations in which multiple species in addition to nanoparticles are present. In addition to the nanoparticle diffusion, two different salts (species) having different properties are considered. A variable magnetic field is applied transverse to the vertical sheet. It is assumed that the surface is in contact with the hot magnetic nanofluid at a temperature which provides a variable heat transfer coefficient. Buongiorno’s model is employed for the nanofluid. It is also assumed that the Oberbeck-Boussinesq approximation is valid and the mixture of nanofluid and salts is homogenous and is in local thermal equilibrium. In addition, the thermal energy equation features cross-diffusion (Soret and Dufour) terms for both components of salts having different concentration. Appropriate similarity transformations are deployed to render the model non-dimensional. The emerging transformed dimensionless non-linear non-dimensional ordinary differential boundary value problem is solved with the robust bvp4c method in MATLAB. Validation with previous studies has been included for special cases of the general model. The simulations show that the addition of nanoparticles and salts, strongly modifies Temperature and nanoparticle and salt 1 and 2 concentrations. With stronger magnetic field the velocity is suppressed as is momentum boundary layer thickness whereas temperatures are boosted.

Radiative Mixed Convection Flow of Casson Nanofluid through Exponentially Permeable Stretching Sheet with Internal Heat Generation

This paper investigates the mixed convection boundary-layer flow of Casson nanofluid with an internal heat source on an exponentially stretched sheet. The Buongiorno model, incorporating thermophoresis and Brownian motion, describes fluid temperature. The modeled system is solved numerically using bvp4c routine to analyze the impact of different fluid parameters on velocity, temperature, and concentration profiles. The analysis reveals that the suction effect, magnetic field, and Casson parameter reduce momentum boundary layer thickness and hence slow fluid motion. Conversely, buoyancy forces increase mass boundary layer thickness which results in accelerating fluid motion. Temperature and concentration profiles show similar trends for Brownian motion, radiation, and thermophoresis.

Estimation of the concentration boundary layer adjacent to a flat surface using computational fluid dynamics

Dissolution-permeation (D/P) experiments are widely used during preclinical development due to producing results with better predictability than traditional monophasic experiments. However, it is difficult to compare absorption across in vitro setups given the propensity to only report apparent permeability. We therefore developed an approach to predict the concentration boundary layer for any D/P device by using computational fluid dynamics (CFD). The Navier-Stokes and continuity equation in 2D were solved numerically in MATLAB and by finite element methods in COMSOL v6.1 to predict the momentum (ηf′) and concentration ηg boundary layer for a flow over a flat plate, i.e. the classical Blasius boundary layer flow. A MATLAB algorithm was developed to calculate the edge of either boundary layer. The methodology to determine the concentration boundary layer based on Blasius’s analysis provided an accurate estimate for both ηf′ and ηg, resulting in, ηf′/ηg, at high Schmidt numbers (Sc ∼ 1000) within 14 % of the Blasius solution and 6.6 % of the accepted Schmidt number correlation (Sc1/3=ηf′/ηg). The methodology based on the Blasius analysis of the concentration boundary layer using velocity and concentration profiles computed using CFD presented herein will enable characterization/analysis of complex D/P apparatuses used in preclinical development, where an analytical solution may not be available.

Thermal radiative and Hall current effects on magneto-natural convective flow of dusty fluid: Numerical Runge–Kutta–Fehlberg technique

This research article intends to examine the consequences of Hall impact on the natural convection of magnetohydrodynamic (MHD) fluid flowing and the thermal characteristics of the fluid flow which containing dusty particles via a vertical stretchable sheet. Slip velocity and convective boundary conditions are taken into consideration in this research article. The flow is mathematically described by partial differential equations. The governing equations are renovated into a group of nonlinear differential equations with the use of similarity conversations, which are then resolved numerically by applying Runge–Kutta–Fehlberg. The behavior of these physical factors on the rapidity and temperature profiles of the dust and fluid phases are exposed graphically in this article. Furthermore, frictional force and heat transfer are also examined and discussed. According to the investigation, the existence of suspended particles in the fluid lead to increment in momentum and thermal boundary layer thickness. The temperature of the fluid seems can be controlled by the significant parameter, such as it seem to be increase due to the magnetic, radiation, and Hall parameters, while it is seen to have decreased due to the slip thermal parameter. While the radiation accelerates up the fluid velocity, the magnetic parameter is excellent at slowing it down. The fluid phase’s temperature and velocity profiles are almost usually higher than those of the dust phase. The outcomes contribute to a better understanding of the two-phase theory’s fluid flow phenomenon.

Nonsimilar mixed convection analysis of ternary hybrid nanofluid flow near stagnation point over vertical Riga plate

PurposeThis work aims to concentrate on the mixed convection of the stagnation point flow of ternary hybrid nanofluids towards vertical Riga plate. Aluminum trioxide (Al2O3), silicon dioxide (SiO2) and titanium dioxide (TiO2) are regarded as nanoparticles, with water serving as the base fluid. The mathematical model incorporates momentum boundary layer and energy equations. The Grinberg term for the viscous dissipation and the wall parallel Lorentz force coming from the Riga plate are taken into consideration in the context of the energy equation.Design/methodology/approachThrough the use of appropriate nonsimilar transformations, the governing system is transformed into nonlinear nondimensional partial differential equations (PDEs). The numerical method bvp4c (built-in package for MATLAB) is used in this study to simulate governing equations using the local non-similarity (LNS) approach up to the second truncation level.FindingsNumerous graphs and numerical tables expound on the physical properties of the nanofluid temperature and velocity profiles. The local Nusselt correlations and the drag coefficient for pertinent parameters have been computed in tabular form. Additionally, the temperature profile drops while the velocity profile increases when the mixed convection parameter is included to oppose the flow.Originality/valueThe fundamental goal of this work is to comprehend how ternary nanofluids move towards a vertical Riga plate in a mixed convective domain with stagnation point flow.

Turbulent boundary layers in thermal convection at moderately high Rayleigh numbers

In this work, we perform direct numerical simulations of Rayleigh–Bénard convection in a two-dimensional confined square cell for Rayleigh numbers (Ra) from 109 to 1013 and a Prandtl number (Pr) of 0.7. In contrast to a previous study in a periodic box conducted by Zhu et al. [Phys. Rev. Lett. 120, 144502 (2018)], our simulations apply two adiabatic sidewalls. In particular, boundary layer structures near the heating plates are examined using both mean velocity and temperature profiles in the impacting, shearing, and ejecting regions of the plumes. After an appropriate normalization using the wall units, the friction Reynolds numbers of our simulations exceed the critical value of 200 and follow Reτ∼Ra0.323, and we also observe the logarithmic mean velocity profiles (with the slope κv≈0.35) in the shearing regions and logarithmic mean temperature profiles (with the slope κθ≈2) in the ejecting regions. These logarithmic behaviors indicate that both the thermal and momentum boundary layers may have entered the fully developed turbulent state. However, for the Nusselt number (Nu), our data still follow the trend of classical 1/3 scaling, differing from the ultimate state reported before but agreeing with the three-dimensional results obtained by Iyer et al. [PNAS 117, 14 (2020)] for confined cells.

EMHD stagnation point flow of dusty hybrid nanofluid over a permeable stretching sheet: Radiative solar applications

The primary objective of this paper is to investigate the impact of dusty hybrid nanofluid electromagnetohydrodynamics (EMHD) on the stagnation point flow in the presence of solar radiation. Base fluids contain ethylene glycol, water, silver, titanium alloy, and suspended dust particles. Nonlinear differential equations with two or more independent variables define fluid flow phenomena. The governing equations can be solved by the MATLAB solver by employing a suitable numerical method, like R–K fourth order via shooting method. The isothermals for various parametric values have been explained. Because it has the potential to greatly advance the disciplines of industrial and thermal engineering, this proposed model is useful. When compared to using a single base fluid, the combination of two additional base fluid qualities provides noteworthy results. Because we were able to acquire a lower freezing point than water and better heat conductivity than pure ethylene glycol when we employed the combination of the two base fluids. Glycol water is used in car coolant and solar heating systems for a variety of purposes. Impact of embedded physical quantities like electric field parameter, ratio of specific heat, porosity parameter, stagnation parameter, radiation parameter, heat source parameter, and fluid particle interaction parameter for both velocity and temperature are illustrated graphically. Dust particles have a notable impact on various sectors, including the food and pharmaceutical industries. Specifically, they are special importance in applications such as wastewater treatment, solids drying, and the presence of plastic-coated metal items. In the present work, we observe that the stagnation parameter enhances the momentum boundary layer (MBL) thickness because the dusty fluid dominates the dusty hybrid nanofluid while incorporating the Ag + Ti alloy/EG + Water. The radiation becomes more efficient at evenly spreading heat, potentially resulting in a more uniform temperature distribution. Silver and titanium alloy particles may affect the thermal conductivity of dusty hybrid nanofluid when compared to the dusty fluid. The porosity parameter enhances the fluid flow and penetration by the porous medium, which lowers friction between the skin and the surface and reduces resistance.

Direct numerical simulation of momentum and scalar internal boundary layers

Direct numerical simulations (DNS) of turbulent open channel flow are performed to study and compare momentum and scalar internal boundary layers (IBL). An internal boundary layer (IBL) forms when a turbulent boundary layer is subjected to heterogeneous surface conditions. For example, a momentum IBL forms with a change in surface roughness and a scalar IBL forms due to a localised heat flux. Momentum IBLs are simulated using both a streamwise-varying roughness body forcing technique and a streamwise-varying wall shear stress. Passive scalar IBLs are simulated using both streamwise-varying scalar wall values and wall fluxes, for a homogeneous smooth wall. The roughness body forcing model is shown to reproduce the same IBL features as with the explicitly resolved roughness study of Rouhi et al. (2019), but at a reduced cost. Three common IBL detection methods are employed to estimate the power-law exponents in the growth rates of the IBL. The exponents for the momentum IBL cases are typically less than 0.7 for these methods, smaller than for the scalar-analogues of these methods. Furthermore, we analyse the streamwise variation of the root-mean-square wall-normal (vertical) velocity. We find that the ‘diffusion analogy’, or that momentum and scalar IBLs behave similarly, may not be an appropriate assumption, especially for rough-to-smooth transitions for momentum IBLs.

Computational analysis of Carreau fluid flow in presence with buoyancy force, viscous dissipation, and chemical reaction

Abstract This study presents the computational analysis of heat and mass transfer of an in-compressible electrically conducting non-Newtonian Carreau fluid flow in the presence of buoyancy forces, viscous dissipation, chemical reaction, and heat source/sink. Mathematical modeling is made subject to an inclined disk, which is linearly stretching and also momentum, thermal, and concentration boundary layer are used to simplify laws of fluid mechanics. A similarity transformation is implied to convert the governing system of PDE's into system of ordinary differential equations and numerical solution is obtained by the Software Matlab. The impact of pertinent parameters involved in the velocity, temperature, and concentration profiles are shown through graphs and the results for Sherwood number, skin friction, and Nusselt number are demonstrated through the tables.

Investigating the Impact of Magnetohydrodynamic (MHD) and Radiation on the Casson-Based Nanofluid Flow over a Linear Stretching Sheet in a Porous Medium with Heat Source or Sink

This study delves into the magnetohydrodynamic (MHD) flow of Casson-based nanofluids over a linear stretching sheet, accounting for multiple influencing factors. These findings offer significant real-time applications across a spectrum of fields, including energy generation, environmental engineering, and materials science. The acquired insights into Casson-based nanofluid behaviour within magnetohydrodynamic contexts can foster efficiency improvements, energy conservation, and enhanced overall system and process performance. Furthermore, the current study aims at Casson-based nanofluid's magnetohydrodynamic flow across a linear stretching sheet considering effects of thermal radiation, heat source/sink, and porosity. The governing equations are converted to ordinary differential equations by using similarity transformations. The Runge-Kutta-4 method, along with the shooting technique, is used to solve the reduced equations. The effects of dimensionless parameters, magnetic, Casson, thermophoresis, thermal radiation, and Brownian motion on velocity, thermal, and concentration profiles are considered in the study. As the magnetic and Casson parameters are increased, the findings indicate a reduction in the thickness of the momentum boundary layer. Moreover, the fluid temperature intensifies with the enhancement of thermophoresis and Brownian motion of particles. Finally, for various combinations of applied parameters, the values of skin friction coefficient, Nusselt number, and Sherwood number are obtained and are shown in the tables. The research is unique in a way that incorporates the impacts of heat source/sink and porosity as well as a more precise description of Casson nanofluid flow when compared to earlier findings. The novelty of the investigation lies in the implementation of a heat source/sink and porosity to obtain refined Casson nanofluid flow.

LDV measurements of boundary layer velocity profiles on flat plates with different surface roughnesses

The dynamics acting upon thin flat plates submerged in a fluid are chiefly governed by the delicate boundary layer enveloping their surfaces. Through a series of experiments, we investigated the impact of surface roughness elements on the boundary layer adjacent to a flat plate across a range of Reynolds numbers. The experiments were performed in the Chungnam National University-Cavitation Tunnel (CNU-CT). Three flat plates, each characterized by distinct surface roughness heights denoted by k, were subjected to scrutiny. One boasted a pristine smoothness, while the others bore the deliberate roughness of sandpaper, each with its own unique texture. With precision instrumentation, including Laser Doppler Velocimetry (LDV), we meticulously documented the axial velocity profile and the RMS (Root Mean Square) velocity at strategic points along the flat plates. Through these measurements, we unveiled the boundary layer's thickness, δ, and momentum thickness, θ, elucidating their variations under differing free-stream velocities. As our exploration deepened, the relationship between the local Reynolds number, Rnx, and the non-dimensional velocity profiles, u+ − y+, became apparent. A systematic shift along the log-law line ensued, with both u+ and y + increasing in tandem with the rise in Rnx. Yet, our inquiry did not conclude with observation alone. Employing empirical rigor, we quantified the drag forces acting upon flat plates of varying roughness heights, deriving them from the measured momentum thickness across a range of local Reynolds numbers, Rnx.