Analysis Of Two-dimensional Flow Research Articles

Heat transfer analysis of mixed convection boundary layer blood base nanofluids with the influence of viscous dissipation

In this research study, we delve into the analysis of two-dimensional boundary layer incompressible viscous flow of blood based nanofluids, incorporating a couple stress model. This investigation encompasses considerations of heat transmission and viscous dissipation effects. Specifically, focus on a particular type of nanoparticle, Magnesium oxide (MgO), dispersed in blood, the base fluid. By employing suitable similarity transformations, transform a set of partial differential equations (PDEs) into nonlinear ordinary differential equations (ODEs). To leverage the Homotopy Analysis Approach (HAM) to solve this system of equations. This study discerns the impacts of various factors on temperature and velocity distributions. Visualization through graphs depicting nanoparticle volume concentration, magnetic field strength, couple stress parameter, Eckert number, and Prandtl number aids in presenting our findings. These insights illuminate the intricate interplay among different parameters and offer insights for enhancing heat transfer in blood-based nanofluids. Additionally, scrutinize the thermal performance of the blood-based nanofluid, assessing the Nusselt number and local skin friction coefficient. Such analysis holds significance for ensuring patient safety and treatment efficacy, particularly in medical procedures involving blood circulation, where mixed convection plays a pivotal role. Understanding these dynamics is crucial for the design and optimization of various medical devices and therapies, ensuring optimal temperature maintenance during blood circulation-related operations.

Stability Analysis of Two-Dimensional Ideal Flows With Applications to Viscous Fluids and Plasmas

Abstract We are interested in the stability analysis of two-dimensional incompressible inviscid fluids. Specifically, we revisit a known recent result on the stability of Yudovich’s solutions to the incompressible Euler equations in $L^{\infty }([0,T];H^{1})$ by providing a new approach to its proof based on the idea of compactness extrapolation and by extending it to the whole plane. This new method of proof is robust and, when applied to viscous models, leads to a remarkable logarithmic improvement on the rate of convergence in the vanishing viscosity limit of two-dimensional fluids. Loosely speaking, this logarithmic gain is the result of the fact that, in appropriate high-regularity settings, the smoothness of solutions to the Euler equations at times $t\in [0,T)$ is strictly higher than their regularity at time $t=T$. This “memory effect” seems to be a general principle that is not exclusive to fluid mechanics. It is therefore likely to be observed in other setting and deserves further investigation. Finally, we also apply the stability results on Euler systems to the study of two-dimensional ideal plasmas and establish their convergence, in strong topologies, to solutions of magnetohydrodynamic systems, when the speed of light tends to infinity. The crux of this asymptotic analysis relies on a fine understanding of Maxwell’s system.

Numerical Simulation and Computational Fluid Dynamics Analysis of Two-Dimensional Lid-Driven Cavity Flow Within the Weapon Bay of an Autonomous Fighter Drone

The efficient deployment of weapons in military operations is critical for mission success, and the flow of air within the weapon bay of an autonomous fighter drone plays a vital role in achieving this objective. In this paper, we present a comprehensive numerical simulation and computational fluid dynamics (CFD) analysis of the three-dimensional lid-driven cavity flow within the weapon bay of an autonomous fighter drone. To address this challenging problem, we employ CFD analysis and a multigrid approach to solve the Navier-Stokes equations for the aerodynamic problem. Our simulations include high Reynolds numbers of up to 10,000, which demonstrates the potential of CFD analysis in optimizing the design of autonomous fighter drones for military operations. We evaluate the effectiveness of the linked strongly implicit multigrid technique in estimating high-Re fine-mesh flow solutions using the vorticity-stream function formulation of the two-dimensional incompressible Navier-Stokes equations. The model issue is the driven flow in a square cavity, and we consider meshes up to 1024 x 1024 points and combinations with Reynolds numbers as high as 1000. To further improve the accuracy of our simulations, we employ one-dimensional grid clustering coordinate transformations instead of uniform mesh refinement, as the flow field exhibits one or more secondary vortices. Our findings demonstrate that CFD analysis can provide valuable insights into the complex flow dynamics within the weapon bay of autonomous fighter drones, which can lead to the optimization of their design for enhanced mission capabilities. Overall, our study highlights the significance of numerical simulations and CFD analysis in the design and optimization of autonomous fighter drones for military applications. Our results can serve as a basis for future research in the field of UAV aerodynamics and contribute to the development of more efficient and effective military operations.

Thermal boundary layer depletion in minichannels by electrohydrodynamic conduction pumping

The article presents a numerical analysis of two-dimensional laminar flow and heat transfer in a minichannel with flat plate electrode pairs periodically flushed to the bottom wall. The two-way coupled governing equations of flow, heat transfer, electric potential and charge conservation are solved using the opensource finite-volume framework of OpenFOAM. Two cases of the minichannel at completely horizontal (case A) and 90° bent (case B) configurations are considered. The inlet laminar flow with Reynolds number varying from 10 to 1000 has been taken into account. The applied electric potential is varied in three steps 0, 0.5 and 1 kV. Electrohydrodynamic (EHD) conduction pumping due to the residual conductivity of the working fluid and the electric-field enhanced dissociation of free charges generate vortices in the proximity of electrodes. The flow and thermal performance of the minichannel in the presence of EHD conduction induced vortices are quantified in terms of pressure drop, Nusselt number and a performance factor (which is a combined function of pressure drop and Nusselt number). The vortices generated by EHD conduction pumping phenomenon deplete the thermal boundary layer, aid mixing and enhance the heat transfer. The mean and local Nusselt numbers are notably increased with only a minimal raise in pressure drop. In both the configurations of the minichannel, the performance factor is greater than 1 for the entire parameter space considered in this study. However, the thermal boundary layer depletion and heat transfer enhancement is prominent at low Reynolds number flows. The maximum drop in performance factor from case A to case B is only 18.5%. Results of this study indicate that EHD conduction pumping is a potential technique to enhance heat transfer in minichannels with minimum additional power consumption.

Development and application of a user-friendly general-purpose predictive simulation tool for two-dimensional flow analysis

Development and application of a user-friendly general-purpose predictive simulation tool for two-dimensional flow analysis

Significance of Weissenberg Number, Soret Effect and Multiple Slips on the Dynamic of Biconvective Magnetohydrodynamic Carreau Nanofuid Flow

This study focused on the analysis of two-dimensional incompressible magnetohydrodynamic Carreau nanofluid flow across a stretching cylinder containing microorganisms with the impacts of chemical reactions and multiple slip boundary conditions. Moreover, the main objective is concerned with the enhancement of thermal transportation with the effect of heat source and bioconvection. By assigning pertinent similarity transitions to the governing partial differential equations, a series of equations (ODES) is generated. An optimum computational solver, namely the bvp5c software package, is utilized for numerical estimations. The impact of distinct parameters on thermal expansion, thermophoresis, and the Nusselt number has been emphasized, employing tables, diagrams, and surface maps for both shear thinning (n < 1) and shear thickening (n > 1) instances. Motile concentration profiles decrease with Lb and the motile microorganism density slip parameter. It is observed that with increasing values of Pr, both the boundary layer thickness and temperature declined in both cases. The Weissenberg number demonstrates a different nature depending on the type of fluid; skin friction, the velocity profile and Nusselt number drop when n < 1 and increase when n > 1. The two- and three-dimensional graphs show the simultaneous effect of involving parameters with physical quantities. The accuracy of the existing observations is evidenced by the impressive resemblance between the contemporary and preceding remedies.

Numerical simulation of two-dimensional biomagnetic shear flow

The current work focuses on numerical analysis of two-dimensional simple shear flow of biomagnetic fluid flowing in the vicinity of non-uniform magnetic field. Accordingly, the numerical model is constructed with the help of semi-implicit fractional step algorithm utilizing a finite volume method to solve the corresponding continuity and Navier-Stokes equations. Numerical simulations are mainly focussed on changing Reynolds number (Re), magnetic number (Mn) and Stuart number(N). The results reveal that multiple recirculation zones emerge as a result of the combined influence of flow and magnetic field. Out of the three parameters considered, the formation of vortices is not affected by variation of Stuart number compared to Reynolds and magnetic numbers.

GPU based lattice Boltzmann simulation and analysis of two-dimensional trapezoidal cavity flow

In this study, we utilize the lattice Boltzmann method to investigate the flow behavior in a two-dimensional trapezoidal cavity, which is driven by both sides on the upper wall and lower wall. Our calculations are accelerated through GPU-CUDA software. We conduct an analysis of the flow field mode by using proper orthogonal decomposition. The effects of various parameters, such as Reynolds number (<i>Re</i>) and driving direction, on the flow characteristics are examined through numerical simulations. The results are shown below. 1) For the upper wall drive (T1a), the flow field remains stable, when the <i>Re</i> value varies from 1000 to 8000. However, when <i>Re</i> = 8500, the flow field becomes periodic but unstable. The velocity phase diagram at the monitoring point is a smooth circle, and the energy values of the first two modes dominate the energy of the whole field. Once <i>Re</i> exceeds 10000, the velocity phase diagram turns irregular and the flow field becomes aperiodic and unsteady. 2) For the lower wall drive (T1b), the flow is stable when <i>Re</i> value is in a range of 1000－8000, and it becomes periodic and unsteady when <i>Re</i> = 11500. The energy values of the first three modes appear relatively large. When <i>Re</i> is greater than 12500, the flow field becomes aperiodic and unsteady. At this time, the phase diagram exhibits a smooth circle, with the energy values of the first two modes almost entirely dominating the entire energy. 3) For the case of upper wall and lower wall moving in the same direction at the same speed (T2a), the flow field remains stable when <i>Re</i> changes from 1000 to 10000. When <i>Re</i> varies from 12500 to 15000, the flow becomes periodic and unstable. The velocity phase diagram is still a smooth circle, with the first two modes still occupying a large portion of the energy. Once <i>Re</i> exceeds 20000, the energy proportions of the first three modes significantly decrease, and the flow becomes aperiodic and unsteady. 4) For the case in which the upper wall and lower wall are driven in opposite directions at the same velocity (T2b), the flow field remains stable when <i>Re</i> changes from 1000 to 5000. When <i>Re</i> = 6000, the energy of the first mode accounts for 86%, and the flow field becomes periodic but unstable. When <i>Re</i> exceeds 8000, the energy proportions of the first three modes decrease significantly, and the flow field becomes aperiodic and unsteady.

Numerical investigation and improvement of the aerodynamic performance of a modified elliptical-bladed Savonius-style wind turbine

<abstract> <p>The Savonius turbine has an advantage over other types of vertical axis wind turbines (VAWT), which have speeds ranging from the lowest wind speed to the highest. However, the main problem is the negative torque on the rotary blades. This paper used computational fluid dynamics to numerically investigate the two-dimensional flow analysis of a modified elliptical Savonius wind turbine. This study investigated and compared five rotor blades: Classic, elliptical, and their three modifications. The behavior of wind energy was studied explicitly by changing the angle of the axis of the elliptical blade from the concave side, which leads to a convex shape to increase the area affected by the thrust force and increase the positive torque. The ANSYS (previously known as STASYS Structural Analysis System) Fluent version 15 software solves the unstable Reynolds-Naiver-Stokes (URAN) equation. The coupling algorithm solves the pressure-based coupling pressure velocity using the ANSYS Fluent. In the simulation, the drag, lift, and moment coefficients on the Savonius turbine were calculated directly at each change in the axis angle. The test results at wind speeds of up to nine m/s showed that the modified elliptical turbine with an axis angle of 50° had the highest coefficient power (Cp) among other elliptical blade modifications. In comparison, the test results with variations in wind speeds of 4–12 m/s showed that turbines with an axis angle of 55° performed better with a higher tip speed ratio (TSR) than other models.</p> </abstract>

Statistical Analysis of MHD Flow of an Electrically Conducting Tangent Hyperbolic Fluid over a Stretching Cylinder with Convective Boundary Condition

The dynamics of MHD non-Newtonian fluid flow past a cylinder with slip boundary condition and magnetic field is addressed in this study. The non-Newtonian fluid (tangent hyperbolic) considered in this study are nail polish and whipped cream. This article investigates the statistical analysis of two-dimensional MHD tangent hyperbolic fluid flow over a cylinder with slip condition. The partial differential equations describing the problem are later transformed into the ordinary differential equation by similarity variables. The derived model is solved by the spectral homotopy analysis method (SHAM). The characteristics of the parameters of the flow are demonstrated by the velocity of the flow. The skin friction coefficient is computed and presented with the aid of a tables. The slope of the linear regression is obtained through the data points while bar charts for engineering quantities of interest are presented. The findings indicated that an increase in magnetic parameters builds a resistance to the flow. Also, it was discovered that the radius of curvature decreases when the curvature parameter increases.

Cooling of Heated Blocks with Triangular Guide Protrusions Simulating Printed Circuit Boards

There is no study that investigates triangular guide protrusions including their systematical geometrical changes together with the effects of channel height in the open literature in the context of the authors’ knowledge. Moreover, the number of laminar studies is less than turbulent studies, whereas low velocity or natural convection cases are still important, especially for small devices in small PCB passages. The objective of this study is to investigate numerically the effects of triangular guide protrusions for the enhancement of heat transfer from the blocks’ simulated electronic components in laminar flow conditions. Two-dimensional, incompressible, steady, and laminar flow analysis was performed to predict fluid flow and heat transfer characteristics for three heated blocks in a PCB (printed circuit board) passage with triangular guide protrusions mounted on the upper wall. The Galerkin finite element method of weighted residuals was used to discretize conservation equations. The effects of the channel expansion ratio and inlet velocity were investigated for five geometrical cases. If the size of the protrusions is increased, the existence of protrusions starts to affect the flow patterns on the lower wall. The size of the last protrusion controls the flow structure downstream of the last block. On the upper wall, after the last protrusion, a recirculation is formed and the length of the recirculation increases with an increasing Re number. Moreover, the reattachment length of recirculation after the last block increases with an increasing Reynolds number for a fixed expansion ratio. Expansion ratio and inflow conditions caused by blocks and protrusions have a great influence on the formation of secondary recirculation in addition to the Reynolds number. Heat transfer increases with increasing sizes of upper triangular protrusions. Maximum overall heat transfer enhancement is provided as 47.7% with the geometry of the maximum sized protrusions for the channel height of 3 h. In the case of 4 h, the maximum overall heat transfer enhancement is 24.21%. These enhancements in heat transfer that can be encountered in PCB cooling applications may help the PCB cooling designers.

Thermal efficiency and stability of copper-alumina nanoparticles with Darcy-Forchheimer effects

The main objective of the current study is to find dual branches with stability analysis of two-dimensional (2D) flow and heat transport of water-based hybrid nanofluid on a linear shrinking/stretching sheet with effects of the thermal radiation and convective condition. The effect of Darcy-Forchheimer has also been considered. A permeable surface is referred to sustain a shrinking flow by a sufficient mass suction of the wall. The system of governing boundary layer partial differential equations (PDEs) is transformed into ODEs by employing similarity transformation. The bvp4c solver is used as a numerical computing tool in the MATLAB software to solve the resultant ODEs and the outcomes are offered in graphs and tables. Our computational results revealed dual branches of solutions possessed by the shrinking parameter i.e. . The increment number of copper volume fraction can increase the range of two branches, while the thermal radiation and Biot parameters have zero effect on delaying the separation of boundary layers along with porosity and inertia parameters. Increased suction and Biot parameters can raise the rate of heat transfer while the opposite effect is achieved by enhancing the magnitude of .

Development and Application of a User-Friendly General-Purpose Predictive Simulation Tool for Two-Dimensional Flow Analysis

Development and Application of a User-Friendly General-Purpose Predictive Simulation Tool for Two-Dimensional Flow Analysis

Computational Analysis of the Rotating Cylinder Embedment onto Flat Plate

The Magnus effect and its evolution have greatly affected the aerospace industry over the past century to date. Nevertheless, cylinder embedment onto a flat plate offers a new discovery that is yet to be investigated, specifically whether the concept could enhance the aerodynamic properties of the flat plate following the Magnus effect momentum injection. Over the past decade, the use of a rotating cylinder on an aerofoil has existed from past researches studies where the embedment has significantly increased in its aerodynamic performance better than the one without Magnus application. However, it would be hard to achieve experimental-wise as an accurate measurement and fabrication would be needed to have the same resulting effects. Here, most of the researchers would not focus deeply on the placement of the cylinder as this may increase their fabrication and testing complications. Therefore, the current study delineates the use of flat plate as the foundation design to encounter the arise matter by reducing its complication yet easy to manufacture experimentally. In this work, the model output was evaluated by using ANSYS WORKBENCH 2019 software to simulate two-dimensional flow analysis for the rotational velocities of 500 RPM and 1000 RPM, respectively. This was done for different Reynolds numbers ranging from 4.56E+05 to 2.74E+06 which implicitly implied with free stream velocities varying from 5 m/s to 30 m/s for different angles of attack between 0 to 20 degrees. Prior to developing the best model embedment, the mesh independency test was validated with an error of less than 1%. The study resulted in a remarkable trend that was noticeably up to 32% (500 RPM) and 76% (1000 RPM) better in compared to the one without momentum injection. Similarly, the high recovery led to a tremendously lower of 51% (500 RPM) and 99% (1000 RPM), respectively. In sum, these findings generated a stall angle delay of up to 26% (500 RPM) and 78% (1000 RPM) accordingly.

Estimating output flow depth from Rockfill Porous media

Abstract To analyze the flow in a rockfill porous media using the Gradually Varied Flows theory (one-dimensional flow analysis) and solving the Parkin equation (two-dimensional flow analysis), calculation of the output flow depth as the downstream boundary condition is of great importance. In most previous studies, the output flow depth has been considered equal to the critical depth. In the rockfill porous media, unlike free surface channels, the fluid weight is exerted to the aggregates in addition to the flow, and therefore, the output flow depth from the rockfill is always greater than the critical depth (flow leaves the rockfill with a specific energy greater than the critical energy), and is expressed as a coefficient (Γ) of the critical depth. In the present study, using dimensional analysis and particle swarm optimization (PSO) algorithm and experimental data in different conditions (a total of 178 experimental data for rounded, crashed, Glass artificial materials with rhomboid structure, Glass artificial materials with cubic structure, sandy natural materials), an equation was presented to calculate the mentioned coefficient as a function of the physical characteristics of the rockfill porous media as well as the flow that can be used for all experimental conditions with high accuracy. If the output flow depth is considered to be equal to the critical depth, the mean relative error (MRE) in terms of using the experimental data of the mentioned materials separately and for the data of all the mentioned materials together was equal to 84.40, 83.81, 60.62, 67.68, 74.82 and 69.96%, respectively. In the case of using the proposed equation in the present study, the corresponding values of 5.49, 4.72, 6.24, 4.41, 6.42 and 8.99% were calculated, respectively.

Computational Fluid Dynamics Study of NACA 0012 Airfoil Performance with OpenFOAM®

Numerical methodologies have been implemented in most recent years in order to predict the lift and drag coefficients, the flow velocity, and the pressure distributions around the airfoil profiles in order to develop powerful computational tools based on the analysis of the main features, which describe the optimal wing or blade performance and predict a functional aerodynamic profile implemented to obtain the better energy efficiency generated, for different airplane designs. Computational Fluid Dynamics (CFD) analysis, computation, and prediction of inviscid and viscous two-dimensional flows are based on unsteady simulations of large systems with linear equations solved in a reasonable amount of computing resources. In this sense, Reynolds Averaged Navier Stokes (RANS) approach is generally applied for simulating the mean quantities of turbulent flows with high efficiency in the solving of differential equations of fluid flows into the control volume. However, Large Eddy Simulations are widely recognized to capture the main turbulent effects in a free stream influenced by the inertial forces of the airfoil displacement. Therefore, this research presents a CFD study of the NACA 0012 airfoil with the aim of checking the level of prediction and the numerical performance methodologies proposed by recent numerical reviews developed to study the description of turbulent flows analyzed with the Navier Stokes equations for incompressible flows with small temperature differences between the airfoil surface, and the air free stream. Numerical results have been analyzed in order to compare URANS and LES data used to predict physical variables and turbulent quantities that perform the airfoil profile in the virtual environment offered by OpenFOAM software.

Topological Characteristics of Obstacles and Nonlinear Rheological Fluid Flow in Presence of Insulated Fins: A Fluid Force Reduction Study

In this work, a comprehensive study of fluid forces and thermal analysis of two-dimensional, laminar, and incompressible complex (power law, Bingham, and Herschel–Bulkley) fluid flow over a topological cross-sectional cylinder (square, hexagon, and circle) in channel have been computationally done by using finite element technique. The characteristics of nonlinear flow for varying ranges of power law index 0.4 ≤ n ≤ 1.6 , Bingham number 0 ≤ Bn ≤ 50 , Prandtl number 0.7 ≤ Pr ≤ 10 , Reynolds number 10 ≤ Re ≤ 50 , and Grashof number 1 ≤ Gr ≤ 10 have been examined. Considerable evaluation for thermal flow field in the form of dimensionless velocity profile, isotherms, drag and lift coefficients, and average Nusselt number Nu avg is done. Also, for a range of Bn , the drag forces reduction is observed for circular and hexagonal obstacles in comparison with the square cylinder. At Bn = 0 corresponding to Newtonian fluid, maximum reduction in drag force is reported.

Numerical and perturbation solutions of cross flow of an Eyring-Powell fluid

This communication presents a comparative analysis of two-dimensional cross flow of non-Newtonian fluid with heat and mass transfer is presented in this article. Eyring-Powell fluid is chosen as the main carrier of heat and nano species through a uniform horizontal channel. Effects of suction are also taken into account by placing porous walls. Main source of the flow is the motion of upper plate that moves with a constant velocity in axial direction. Two different nano flows have been formulated by neglecting and, as well as, applying constant pressure gradient, respectively. In addition to this, the analytical solution is validated with the numerical solution. Perturbation technique is employed to obtain a sustainable solution for the highly nonlinear and coupled differential equations. Further, Range-Kutta method with shooting technique is employed to get an approximate solution. It if inferred that both numerical and series solutions display a complete agreement.

Magnetic field promoted irreversible process of water based nanocomposites with heat and mass transfer flow.

Analytical analysis of two-dimensional, magnetohydrodynamic, heat and mass transfer flow of hybrid nanofluid incorporating Hall and ion-slip effects and viscous dissipation in the presence of homogeneous-heterogeneous chemical reactions and entropy generation is performed. The governing equations are modified with the help of similarity variables. The reduced resulting nonlinear coupled ordinary differential equations are solved with the help of homotopy analysis method. The effects of all the physical parameters are demonstrated graphically through a detailed analysis. The main outcome of the study is the use of applied strong magnetic field which generates the cross flow of hybrid nanofluid along the z-axis. The numerical comparison to the existing published literature is also provided.

Numerical Study of Wind-Tunnel Wall Effects on Lift and Drag Characteristics of NACA 0012 Airfoil

Possible interference effects of the wind tunnel walls play an important role especially for measurements in closed-wall test sections. In this study, a numerical analysis of two-dimensional subsonic flow over a NACA 0012 airfoil at different computational domain heights, angles of attack from 0o to 10o, and operating Reynolds number of 6×106 is presented. The work highlights the role of computational fluid dynamics (CFD) in the investigation of wind tunnel wall effect on lift curve slope correction factor (Ka). The flow solution is obtained using Ansys Fluent software by solving the steady-state continuity and momentum governing equations combined with turbulence model k-v shear stress transport (SST-K?). The numerical results are validated by comparing with the available experimental measurements. Calculations show that the lift curve slope correction results are very close to the published data.