Numerical Analysis Of Flow Research Articles

Drag force acting on the structure due to dam-break flow: effect of porous media and bed slope

ABSTRACT This study presents a numerical analysis of dam-break flow over a solid downstream structure, with a focus on the drag force exerted and the effects of porous media and bed slope. Dam-break events are high-energy phenomena capable of causing significant structural damage, primarily due to the intense forces involved. This research addresses a critical gap in understanding how porous media and bed slope can affect structural impacts in dam-break scenarios. Findings indicate that introducing porous media can reduce the drag force, though the degree of reduction varies with porosity. Similarly, increasing bed slope results in higher drag forces, though this effect is not uniform across slope increments. This study contributes practical recommendations on selecting effective porous media and bed slope configurations to enhance structural resilience in dam-break scenarios. These results, validated against experimental data, provide valuable guidance for both academic research and hydraulic engineering applications.

Numerical Analysis of Flow in U-Type Solid Oxide Fuel Cell Stacks

Numerical analysis of a U-type solid oxide fuel cell stack was performed using computational fluid dynamics to investigate the effects of stack capacities and fuel/air utilization rates on the internal flow uniformity. The results indicated that increasing the fuel/air utilization rate improved the gas flow uniformity within the stack for the same stack capacity. The uniformity in the anode fluid domain was better than that in the cathode fluid domain. Furthermore, the flow uniformity within the stack was associated with the percentage of pressure drop in the core region of the stack. The larger the percentage of pressure drop in the core region, the more uniform the flow inside the stack. Additionally, under a fuel utilization rate of 75%, the computational results exhibited excessively high fuel utilization rates in the top cell of a 3 kWe stack, indicating a potential risk of fuel depletion during actual stack operation.

Numerical solutions and stability analysis of hybrid Casson nanofluid flow with MHD and heat transfer effects

AbstractThis research addresses the complex dynamics of hybrid Casson nanoliquids in flow and heat transfer applications, focusing on the interaction between fluid dynamics and thermal phenomena in the presence of magnetohydrodynamics (MHD), viscous dissipation, and Joule heating. The motivation behind this study stems from the need to enhance the efficiency of heat transfer processes in various engineering applications, such as cooling systems and electronic devices, where hybrid nanofluids can offer superior thermal performance compared to conventional fluids. The novelty of this work lies in its comprehensive numerical investigation of a hybrid Casson nanoliquid over a moving permeable surface, incorporating a detailed analysis of MHD effects, viscous dissipation, and Joule heating. Using the Tiwari and Das model to formulate the governing equations, the study employs similarity transformations to convert these equations into a system of ordinary differential equations (ODEs). MATLAB is then used to derive numerical solutions, with a stability analysis ensuring the physical dependability of these solutions. Key findings reveal that the temperature distribution of the hybrid nanoliquid shows a positive correlation with both Prandtl and Hartmann numbers. Additionally, a positive relationship between temperature and the Eckert number is observed. These insights offer valuable guidance for engineers aiming to optimize heat transfer processes using hybrid nanofluids, highlighting their potential for improved thermal management in practical applications.

Optimizing aerodynamics: Numerical flow analysis for drag and lift reduction in SUV designs

Optimizing aerodynamics: Numerical flow analysis for drag and lift reduction in SUV designs

Reversible esterification process in Casson nanofluids: A numerical analysis of non-newtonian hydromagnetic flow

A computational mechanism has been formulated to scientifically analyze the phenomenon of combined convection in the occurrence of magnetohydrodynamic flow behavior of Casson nanofluid. This study emphasizes the trajectory of the nanofluid along a stretching sheet with nonlinear permeability, while considering additional physical effects such as reversible chemical reaction, thermal radiation, energy source/sink, suction and viscous dissipation. In this study, we have additionally integrated the nanofluid paradigm proposed by Buongiorno, which encompasses the repercussion of thermophoresis along with Brownian motion. The utilization of appropriate similarity renovations serves the purpose of recasting the dominant multivariate differential equations to a collection of nonlinear differential equations in single variable. The Runge–Kutta shooting mechanism is implemented for the intention of numerically determining the unknown boundary conditions. The solution to the dominant equations was obtained by employing the fourth-order Runge–Kutta technique and to ensure the dependability of the outcomes, the bvp4c method was employed. The graphical and tabulated observations are presented herein to facilitate a comprehensive analysis of the underlying physical characteristics inherent in the problem at hand. The utilization of the Casson parameter has been found to be advantageous in the reduction of shear stress rate, along with the enhancement of mass and energy transfer rates. Additionally, the application of suction has been observed to be beneficial in the enhancement of Sherwood number and energy transfer rate. Within the scope of the context of the esterification process, the purpose of this proposal is to evaluate the impact that numerous arithmetical values exert on the temperature field, the velocity profile and the volumetric concentration. An in-depth graphical analysis that takes into account the relevant physical consequences is used to evaluate the most important factors that relate to the physical quantities that describe the contours of temperature, velocity and concentration. In addition to being accompanied by their respective explanations, the tabular portrayal of the local Sherwood number, shear stress rate along with local Nusselt number all feature in this paper. There is a clear distinction that can be made between irreversible and reversible flows in the evaluation of the local Sherwood number, rate of shear stress and local Nusselt number. This differentiation is brought about by taking into analysis thermophoresis parameter, Brownian motion parameter and suction parameter. The results that were produced from the theoretical simulations have significant repercussions for a variety of fields that are related to energy engineering. The findings derived from the analysis indicate a negative correlation between the Brownian motion parameter and both irreversible and reversible flow in terms of rate of energy transfer and shear stress rate. It is imperative to highlight that reversible flow holds greater significance in comparison to irreversible flow.

Double pass solar air heater with aerofoil and bio-inspired fins: A numerical analysis of thermohydraulic performance

In the present study, a numerical flow analysis is performed on a double pass solar air heater (DPSAH) with a bottom plate surface roughened using aerofoil fins to study its thermohydraulic performance. The experimentally validated DPSAH model was studied considering factors like different fin shapes, diurnal variation of solar radiation, absorber plate material, and the flow conditions at different relative height ratios (h/H) between 0.17 and 0.50 and fin length ratio (l/H) of 0.29. Using the RNG k-ε turbulence model, the relative Nusselt number (Nu/Nus), relative friction factor (f/fs), and thermohydraulic performance factor (THPF) were found for Reynolds number between 3000 and 21000 with an increment of 3000. The maximum enhancements of 4.23 and 2.51 times were achieved in the Nu/Nus and THPF values, respectively, for a Re value of 3000 in a 2-row setup with h/H of 0.50. The DPSAH with bio-inspired fins performed better than optimized aerofoil fins for majority of the tested range even with similar increase in effective heat transfer area. The values predicted using correlations developed in this study and numerically obtained values of the Nusselt number and friction factor matched closely with an extreme deviation of 5 % in f values.

Numerical analysis of flow and heat transfer characteristics in Taylor-Couette-Poiseuille flow utilizing Large Eddy Simulation method

The flow and heat transfer characteristics within the Taylor-Couette-Poiseuille configuration induced by supercritical carbon dioxide flowing through the gap between the turbine shaft and the stationary casing were studied using Large Eddy Simulation. Wavelet analysis was used to calculate pressure fluctuations across various frequencies. Computational assessments were carried out to evaluate changes in the field synergy angle and inertial perturbations within the annular gap. A new theory was introduced to seamlessly integrate temperature, pressure, and velocity fields. Additionally, entropy generation in the Taylor-Couette-Poiseuille flow regime was thoroughly examined. The study revealed the emergence of vortices at the rotating wall, indicating a dynamic process in which large-scale vortices dissolve and more minor ones form. As frequency increases, pressure fluctuations grow. Increasing the mass flow rate can reduce the twisting vortex at the rotating wall and delay the onset of temperature fluctuations. Additionally, increasing the mass flow rate enhances the cooling effect on the rotating shaft. In the radial direction, as r increases, the field synergy angle and the inertial disturbance both show a trend of first decreasing and then increasing. The heat transfer performance is best when r = 0.6 and decreases significantly when r = 0.95. The synergy between the temperature gradient field, pressure gradient field, and velocity field shows a trend opposite to the field synergy angle and the inertial disturbance. As one moves from the rotating wall toward the stationary wall, temperature and velocity entropy production rates decrease, with noticeable fluctuations near the rotating wall.

A numerical analysis of the rotational flow of a hybrid nanofluid past a unidirectional extending surface with velocity and thermal slip conditions

Abstract This work inspects 3D magnetohydrodynamic hybrid nanofluid flow on a permeable elongating surface. The emphasis of this paper is on the study of hybrid nanofluid flow within a rotating frame, taking into account the simultaneous impact of both thermal and velocity slip boundary conditions. The chosen base fluid is water, and the hybrid nanofluid comprises two nanoparticles Cu \text{Cu} and Al 2 O 3 {\text{Al}}_{2}{\text{O}}_{3} . The effect of the magnetic and porosity parameters is taken into account in the momentum equation. The thermal radiation, Joule heating, and heat source are considered in the energy equation. Using a similarity system, we transform the PDEs of the proposed model into ODEs, which are then solved numerically by the bvp4c technique. The magnetic field shows a dual nature on primary and secondary velocities. Enrich magnetic field decreases the primary velocity and enhances the secondary velocity. The rotation parameter has an inverse relation with both velocities. The temperature profile amplified with the escalation in heat source, magnetic field, rotation factor, and Eckert numbers. The skin friction is boosted with magnetic parameters while the Nusselt number drops.

Numerical analysis of blood flow in a branched modular stent-graft for aneurysms covering all zones of the aortic arch.

Due to the anatomical complexity of the aortic arch for the development of stent-grafts for total repair, this region remains without a validated and routinely used endovascular option. In this work, a modular stent-graft for aneurysms that covers all aortic arch zones, proposed by us and previously structurally evaluated, was evaluated from the point of view of haemodynamics using fluid-structural numerical simulations. Blood was assumed to be non-Newtonian shear-thinning using the Carreau model, and the arterial wall was assumed to be anisotropic hyperelastic using the Holzapfel model. Nitinol and expanded polytetrafluoroethylene (PTFE-e) were used as materials for the stents and the graft, respectively. Nitinol was modelled as a superelastic material with shape memory by the Auricchio model, and PTFE-e was modelled as an isotropic linear elastic material. To validate the numerical model, a silicone model representative of the aneurysmal aorta was subjected to tests on an experimental bench representative of the circulatory system. The numerical results showed that the stent-graft restored flow behaviour, making it less oscillatory, but increasing the strain rate, turbulence kinetic energy, and viscosity compared to the pathological case. Taking the mean of the entire cycle, the increase in turbulence kinetic energy was 198.82% in the brachiocephalic trunk, 144.63% in the left common carotid artery and 284.03% in the left subclavian artery after stent-graft implantation. Based on wall shear stress parameters, it was possible to identify that the internal branches of the stent-graft and the stent-graft fixation sites in the artery were the most favourable regions for the deposition and accumulation of thrombus. In these regions, the oscillating shear index reached the maximum value of 0.5 and the time-averaged wall shear stress was close to zero, which led the relative residence time to reach values above 15 Pa-1. The stent-graft was able to preserve flow in the supra-aortic branches.

Numerical Analysis of Blood Flow through Blood Vessels with Atherosclerosis Using the Newtonian Flow Model

Numerical Analysis of Blood Flow through Blood Vessels with Atherosclerosis Using the Newtonian Flow Model

Numerical investigation and sensitivity analysis of MHD ternary nanofluid flow between perforated squeezed Riga plates under the surveillance of microcantilever sensor

Numerical investigation and sensitivity analysis of MHD ternary nanofluid flow between perforated squeezed Riga plates under the surveillance of microcantilever sensor

Numerical analysis of subcooled flow boiling and critical heat flux under variable wall heat flux

This paper presents a numerical analysis of subcooled flow boiling in a vertical pipe through CFD simulation. The study is aimed to investigate the effect of variable heat flux profiles on CHF. To achieve this, a two-phase Eulerian-Eulerian model coupled with the RPI and CHF boiling models is employed for numerical solutions. The variable heat flux profiles examined include linear-increasing, exponential-increasing, and three sinusoidal-shaped profiles. The results highlight that when variable heat flux profiles are utilized, the RPI model lacks reliability, and the CHF boiling model proves to be a more suitable choice. Among the profiles studied, the sinusoidal-shaped profile with a peak in the middle of the tube exhibits the highest CHF value, while the lowest CHF value corresponds to the exponential-increasing heat flux profile. In sinusoidal profiles, as the number of thermal peaks increases, the CHF value decreases, its location shifts towards the pipe's end, and augments the risk of approaching CHF. By illuminating the intricacies of subcooled flow boiling under variable heat flux, this study provides valuable insights for the development of more efficient and reliable heat transfer designs.

Numerical analysis of fluid flow and heat transfer characteristics in single crystal diamond microchannels with ribs and secondary channels

To meet the heat dissipation requirements of high-frequency and high-power electronic devices, single crystal diamond microchannels (SCD-MC) with secondary channels and rib combinations are proposed. The fluid flow and heat transfer characteristics in SCD-MC with various secondary channels and rectangular rib combinations are investigated through numerical simulations. The comprehensive performance and energy saving effect of the microchannel were evaluated by analyzing the factor of merit and entropy generation performance. The results show that the SCD-MC with secondary channels and rib combinations enhance fluid disturbance and increase the solid–liquid contact area, significantly improving heat transfer. When Reynolds number (Re) is 586, compared with the straight microchannel, the average temperature at the bottom of the SCD-MC with rectangular secondary channels and rectangular rib (Case 5) is reduced by 4.8 K, the heat transfer coefficient is increased by 209.8 %, and the factor of merit is improved by 89.2 %. The entropy generation augmentation number of the Case 5 microchannel was the minimum of 0.52, which has the highest energy saving effect. The factor of merit of the Case 5 microchannel exhibits a tendency to first increase and then decrease with the increase of the relative width of the secondary channel (Ψ), the relative width of the rib (Φ), and the relative position of the rib (Π). At Re = 586, Ψ = 0.933, Φ = 0.667, and Π = 0.5, the factor of merit of the Case 5 microchannel is 2.08, indicating the highest comprehensive performance. This finding provides new ideas and methods for the design and application of microchannel thermal management.

Numerical Analysis of MHD Casson Fluid Flow over a Stretching Surface with Chemical Reaction and Variable Thermal Conductivity

The motivation of the current article is to explore the Numerical analysis of MHD Casson fluid flow over a Stretching surface. Three dimensional, non-linear of an incompressible fluid flow in the presence of chemical reaction and variable thermal conductivity is considered. The mathematical model effectively describes the current flow analysis. The Governing equations are simplified with the help of boundary layer approximations. Non-linear coupled equations for momentum, energy and mass transfer are tackled with MATLAB bvp4c. The behavior of various non-dimensional parameters which are involved in the derived set of equations are described and explained in detailed through graph.

Numerical analysis of blood flow in the abdominal aorta under simulated weightlessness and earth conditions

Blood flow through the abdominal aorta and iliac arteries is a crucial area of research in hemodynamics and cardiovascular diseases. To get in to the problem, this study presents detailed analyses of blood flow through the abdominal aorta, together with left and right iliac arteries, under Earth gravity and weightless conditions, both at the rest stage, and during physical activity. The analysis were conducted using ANSYS Fluent software. The results indicate, that there is significantly less variation in blood flow velocity under weightless conditions, compared to measurement taken under Earth Gravity conditions. Study presents, that the maximum and minimum blood flow velocities decrease and increase, respectively, under weightless conditions. Our model for the left iliac artery revealed higher blood flow velocities during the peak of the systolic phase (systole) and lower velocities during the early diastolic phase (diastole). Furthermore, we analyzed the shear stress of the vessel wall and the mean shear stress over time. Additionally, the distribution of oscillatory shear rate, commonly used in hemodynamic analyses, was examined to assess the effects of blood flow on the blood vessels. Countermeasures to mitigate the negative effects of weightlessness on astronauts health are discussed, including exercises performed on the equipment aboard the space station. These exercises aim to maintain optimal blood flow, prevent the formation of atherosclerotic plaques, and reduce the risk of cardiovascular complications.

Fractional numerical analysis of γ-Al2O3 nanofluid flows with effective Prandtl number for enhanced heat transfer

Abstract Nanoparticles have gained recognition for significantly improving convective heat transfer efficiency near boundary layer flows. The characteristics of both momentum and thermal boundary layers are significantly influenced by the Prandtl number, which holds a crucial role. In this vein, the current study conducted a detailed computational analysis of the mixed convection flow of $\gamma$Al$_2$O$_3$-H$_2$O and $\gamma$Al$_2$O$_3$-C$_2$H$_6$O$_2$ nanofluids over a stretching surface. This research integrates an effective Prandtl number, utilizing viscosity and thermal conductivity models based on empirical findings. Additionally, a unique double-fractional constitutive model is debuted to accurately evaluate the effective Prandtl number’s function in the boundary layer. The equations were solved using a numerical technique that combined the finite-difference method with the L$_1$ algorithm. This investigation presents numerical findings related to the velocity, temperature distributions, wall shear stress coefficient, and heat transfer coefficient, contrasting scenarios with and without the effective Prandtl number. The research shows that integrating nanoparticles into the base fluids reduces the temperature of the nanofluid with an effective Prandtl number while enhancing the heat transfer rate irrespective of its presence. Nonetheless, the introduction of a fractional parameter reduced the heat transfer efficiency within the system. Notably, the $\gamma$Al$_2$O$_3$-C$_2$H$_6$O$_2$ nanofluid demonstrates superior heat transfer enhancement capabilities compared to its $\gamma$Al$_2$O$_3$-H$_2$O counterpart but also exacerbates the drag coefficient more significantly. Many practical applications of this study include electronics cooling, industrial process heat exchangers, and rotating and stationary gas turbines in power plants, and efficient heat exchangers in aircraft.

Numerical heat transfer analysis of bio convective flow of non-Newtonian nanofluid with Darcy-Forchheimer effect over a curved stretching surface

The main aim of this study is to investigate the behavior of bio-convective flow of 2nd grade micropolar nanofluid with Darcy-Forchheimer law over a curved porous stretching surface. The fluid flow analysis includes novel aspects such as the nonuniform heat source/sink, Joule heating, magnetic field, chemical reaction, and thermal radiation. Furthermore, the boundary of the stretching surface is acquired the stratification conditions. A suitable conversion method is employed to transform the flow model into a collection of ordinary differential equations, characterized by their nonlinearity. The bvp4c technique on the MATLAB is utilized to acquire numerical solutions for this set of nonlinear equations. The characteristics of various influential parameters on the velocity, temperature, concentration, and microorganism density profiles are observed and discussed. In the present problem, it is observed that by the growth of micropolar parameter enhances the angular fluid velocity. Moreover, larger values of the magnetic parameter, Darcy number, and porosity parameter result in a decrease in the fluid’s linear velocity. The temperature profile exhibits a decreasing pattern with the elevation thermal stratification parameter, while the opposite trend shows by the increment of the radiation parameter and Eckert number. Additionally, the concentration of nanoparticles decreases as the Schmidt number and Brownian motion parameter increases.

Numerical Analysis of Multiphase Flow and Post-Combustion Characteristics in a Top-Blown Converter with Various Operating Parameters

Numerical Analysis of Multiphase Flow and Post-Combustion Characteristics in a Top-Blown Converter with Various Operating Parameters

Hybrid carbon nanotubes flow and heat transfer over a vertical thin needle with suction effect: A numerical and optimisation analysis

The present study aims to provide a numerical and optimisation analysis of the hybrid carbon nanotubes flow over a vertical thin needle under the suction effect. The thin needle is suspended in water-based hybrid nanofluids containing a combination of single- and multi-walled carbon nanotubes. The heat is transported using the mixed convection flow. A mathematical model of partial differential equations (PDEs) is developed subject to boundary conditions. The PDEs system is converted to non-dimensional ordinal differential equations (ODEs) by using the similarity solution method. Then, the first order of the ODEs system is solved in a MATLAB bvp4c function. We innovatively carry out an optimisation process using response surface methodology (RSM) to enhance the efficiency of the numerical experiment data and fill a gap in the optimised analysis. To observe the variation solutions for the reduced skin friction and heat transfer coefficients, several parameters, such as the mixed convection and suction parameters, are altered into several values. The solutions are essential for accurately forecasting the occurrence of boundary layer separation, particularly in the case of dual solutions. Our analysis reveals that the model generates multiple solutions for the opposing flow, and the boundary layer separates slowly due to the suction effect. To complete the research, RSM reveals that the highest value of the nanoparticle volume fraction and suction parameters, as well as the smallest value of the needle size, generate the maximum transmitting heat through the slender needle. Furthermore, both the numerical and RSM results show that hybrid carbon nanotubes perform better than mono‑carbon nanotubes for better practical reference.

Numerical analysis of magnetohydrodynamic free stream and radiative heat transfer flow of nanofluid in a permeable medium over a linearly stretched cylinder with Arrhenius activation energy

This research article explores the transport characteristics of magnetohydrodynamic Newtonian nanofluid flowing past a stretching cylinder in a permeable medium, considering the activation energy effects using Buongiornos mathematical model. Unlike conventional studies employing constant temperature, concentration and density boundary conditions, convective boundary conditions are utilized in this investigation. The analysis incorporates various significant parameters such as magnetic field, joule heating, viscous dissipation, thermophoresis, Brownian motion, Arrhenius activation energy, and chemical reaction. The governing equations in the form of ODEs are obtained by employing similarity variables.The MATLAB built-in solver bvp4c is employed for obtaining the solutions. The impacts of these parameters on the velocity profile, temperature profile, concentration profile, density profile, skin friction coefficient, Sherwood number, and Nusselt number are elucidated through graphical and tabular representations. The results indicate that an increase in the chemical reaction parameter leads to higher nanoparticle concentration distributions, while the activation energy parameter exhibits the opposite trend. This study holds relevance for various practical applications in applied sciences, including nuclear reactor cooling, geothermal reservoirs, chemical engineering, and thermal oil recovery.