Fluid Flow Research Articles

Simulation of the fluid flow pattern and property estimation for bio-diesel plant design

The fluid flow pattern that occurs in the bio-diesel production process is related to viscosity, flow velocity, and pressure. Fluid flow is a paramount cause of failure in pipes in several industries. The heat transfer cause across pipes needs to be analyzed to avoid failure during operation. The simulation and visualization of fluid flow in the plant pipes were developed for the pressure drop along with the length of the pipe. Flow patterns was analyzed using a Computational Fluid Dynamics model approach (CFD). The CFD within the ANSYS environment has three important stages, namely pre-processing, finding solutions, and post-processing. Mesh was generated and the material properties were assigned. The boundary conditions were stipulated, and the process analyzed to ensure convergence of the solution in a stable state. High density of the blend was observed for 40% bio-diesel blend and low density at 5% bio-diesel blend. The results of the correlation analysis shows that density is directly proportional to bio-diesel content. The density-composition depict a uniform increasing density value with percentage bio-diesel mixture content. The viscosity slightly increases with bio-diesel content. There is a clear trend of viscosity increasing proportional to bio-diesel content. The simulation ensures that the parameters for the design and fabrication of the bio-diesel reactor as obtained from the simulation results is optimal.

The Port-Hamiltonian Structure of Continuum Mechanics

In this paper, we present a novel approach to the geometric formulation of solid and fluid mechanics within the port-Hamiltonian framework, which extends the standard Hamiltonian formulation to non-conservative and open dynamical systems. Leveraging Dirac structures, instead of symplectic or Poisson structures, this formalism allows the incorporation of energy exchange within the spatial domain or through its boundary, which allows for a more comprehensive description of continuum mechanics. Building upon our recent work in describing nonlinear elasticity using exterior calculus and bundle-valued differential forms, this paper focuses on the systematic derivation of port-Hamiltonian models for solid and fluid mechanics in the material, spatial, and convective representations using Hamiltonian reduction theory. This paper also discusses constitutive relations for stress within this framework including hyper-elasticity, for both finite and infinitesimal strains, as well as viscous fluid flow governed by the Navier–Stokes equations.

A three-stage plasma model based on one-way coupling of plasma dynamics, ionic motion, and fluid flow: Application to DBD plasma actuators

The scope of this paper is to present a comprehensive approach for simulating low-temperature atmospheric dielectric barrier discharge plasmas. The proposed methodology categorizes the primary physical phenomena: (i) discharge dynamics, (ii) ionic motion, and (iii) fluid flow, according to their respective time scales and simulates each independently. This allows for the use of distinct solution procedures tailored to each of the three stages of the problem. Such separation offers significant flexibility in choosing appropriate models and numerical schemes for each stage, enabling the simulation of complex geometries and large-scale applications without the excessive computational costs associated with a monolithic approach. As a case study, we apply the proposed algorithm to the surface dielectric barrier discharge plasma actuator for flow control, which is powered by alternating high voltages. The algorithm successfully described the actuator’s behavior while maintaining low computational cost. Additionally, a parametric study is conducted to examine the effect of key input parameters on the generated electrohydrodynamic force and the resulting velocity. Finally, an overall assessment of the three-stage model is provided, highlighting its efficiency and accuracy.

Thermal inspection on MHD Prandtl fluid flow past a stretching sheet in the presence of heat generation/absorption and suction/injection

Abstract For the past several years, researchers have been investigating the thermal boundary layer behavior under various assumptions due to contemporary requirements. From the existing literature, it has been noticed that no investigation has been conducted to examine the thermal and mass transport of a magnetohydrodynamic (MHD) flow of a Prandtl fluid past a stretching sheet with heat generation/absorption and suction/injection. To address this gap, this study looks at how the changed thermal flux, heat generation/absorption, and suction/injection affect the convective flow of MHD Prandtl fluid over a stretching surface. The governing system of nonlinear partial differential equations (PDEs) has been reduced to a system of ordinary differential equations (ODEs) through appropriate transformations. The desired numerical solutions of the resulting ODEs have been obtained using the bvp5c MATLAB package. We have analyzed and presented the effects of the physical parameters on the velocity, temperature, and concentration fields using graphs and tables. Also, the drag coefficient, heat, and mass transport rates were examined. Additionally, an entropy analysis has been conducted to explore the reusability of heat production. It has been observed that intensifying the magnetic and porosity parameters reduces the flow velocity while increasing the Eckert number, heat generation parameter, and the Biot number significantly increases the temperature. The concentration drops with an increase in the Schmidt number and the chemical reaction parameter. This study holds significant implications for industries that rely on drug delivery, heat exchanger technology, polymerization, and refining processes.

Simulation of fluid flow with Cuprophan and AN69ST membranes in the dialyzer during hemodialysis.

Hemodialysis is a crucial procedure for removing toxins and waste from the body when kidneys fail to perform this function effectively. This study addresses the need to improve the efficiency and biocompatibility of membranes used in dialyzers. We simulate fluid flow through two types of membranes, Cuprophan (cellulosic) and AN69ST (synthetic), to understand the complex mechanisms involved and quantify key variables such as pressure, concentration, and flow. This study presents a detailed model that applies mass conservation equations and Navier-Stokes principles adapted for porous media, along with heat and mass transfer considerations. The results revealed significant differences in the flow behavior and filtration efficiency between the two membranes, highlighting the superiority of the AN69ST membrane in terms of flow rate and toxin removal. This model serves as a valuable tool for characterizing new porous membranes in dialysis applications, enabling the prediction of the temperature, pressure, and concentration profiles. By providing this information without requiring extensive experimentation, the model complements the design and evaluation of new membranes and, optimizes their development. The ability to predict these profiles is crucial because they directly influence the parameters that determine treatment effectiveness. Moreover, this study underscores the importance of continued innovation in membrane materials and designs, contributing to improved clinical outcomes and treatment efficiency, representing a significant advancement in healthcare.&#xD.

Magnetized peristaltic flow of Sisko nanofluid under thermal radiation and double-diffusive convection with viscous dissipation and slip effects in an asymmetric channel

The phenomenon of peristalsis has gathered significant attention from researchers due to its wide-ranging applications in fields such as biological sciences, industries, and biomechanics. Its practical relevance can be observed in various processes, including blending food in the digestive tract, flow in small blood vessels and the movement of cilia. Inspired by such useful applications, this theoretical study applies an analytical model that examines the movement of magnetically induced Sisko nanofluid in an asymmetric channel considering the factors like viscous dissipation, multiple slip, thermal radiation, and double diffusive convection. The fluid flow was administered using partial differential equations (PDE’s), transformed into a set of interconnected ordinary differential equations. These non-linear equations were further numerically solved by the NDSolve function in Mathematica. According to our outcomes, the temperature profile increases as the thermal slip factor rises. Moreover, the concentration and nanoparticle profile decrease with increasing values of the concentration slip and nanoparticle slip parameters. It can also determine that when the impact of thermal radiation increases, the temperature profile drops. Such a model has practical applications in simulating the small vessel transportation of particle in hemodynamics as well as in the field of biomedical and medical engineering for nanofluid peristaltic pumps.

Analysis of heat transfer of second-grade hybrid nanofluid and optimization using response surface methodology for thermal enhancement

The fluid flow and heat transfer applications in coaxial double-revolving disks are extensive and encompass multiple engineering and scientific disciplines. This study presents a comprehensive heat transfer analysis in a second-grade hybrid nanofluid. The fluid, influenced by variable thermal conductivity, is confined between two rotating disks in a magnetohydrodynamic Darcy-Forchheimer flow. The hybrid nanofluid combines titanium dioxide (TiO2) and cobalt ferrite (CoFe2O4) nanoparticles with engine oil. These issues have not been addressed in previous research. Similarity transformations make flow equations dimensionless. The resulting equations are solved using a semi-analytical approach called the homotopy analysis method (HAM). This approach provides flexibility in selecting the base function and an initial estimate. The temperature profile improved with higher values of the variable thermal conductivity parameter. Furthermore, the heat transfer rate was enhanced by increasing the variable thermal conductivity, the volume fraction concentration of TiO2, and the Reynolds number.The sensitivity analysis is performed using response surface methodology (RSM). Both the R-squared and adjusted R-squared values attain 100%. The heat transfer rate is found to have a maximum sensitivity of 0.50243 towards varying thermal conductivity parameters and a minimum sensitivity of -0.00666 towards magnetic field parameters. The research utilizes RSM to elucidate methods for improving heat transfer. This work offers practical solutions for developing more efficient thermal management systems. This research provides practical strategies for improving thermal management systems. These solutions are especially useful in rotating machinery-intensive industries. Designing biochemical and pharmaceutical microfluidic pumps and mixers requires understanding hybrid nanofluid flows between spinning disks.

Hybrid molecular-scale and continuum modeling of two-dimensional flow between inhomogeneous solid surfaces and its application to the thrust bearing.

The flow equations are derived for describing the two-dimensional hybrid molecular-scale and continuum flows in the very small surface separation with inhomogeneous solid surfaces and they can be applied for designing the specific bearings. The aim of the present study is to solve this specific flow problem in engineering with normal computational cost. The flow factor approach model describes the flow of the molecule layer adjacent to the solid surface and the Newtonian fluid model describes the flow of the intermediate continuum fluid. By using these flow equations, the simulation results show that designing the inhomogeneous stationary surface can very significantly improve the load-carrying capacity of the hydrodynamic thrust bearing with low clearances. The flow of the physically adsorbed layer is treated as non-continuum and it is modeled by the equivalent non-continuum flow model by considering the fluid molecules orientated normal to the solid surface. The fluid between the two adsorbed layers is treated as continuum and Newtonian. The slippage can occur between the adsorbed layer-solid surface interface. It is assumed as absent on the adsorbed layer-continuum fluid interface. The flow equations are derived according to the equilibrium of the momentum transfer in the surface clearance. The film pressures and carried load of the thrust bearing with low clearance and inhomogeneous surfaces are derived by applying the obtained flow equations.

Towards a standard application of the Reynolds number in studies of aquatic animal locomotion.

Nondimensional groups of measured quantities enable comparison between measurements of animals under different conditions and comparison between species. One of the most used such group is the Reynolds number, which compares inertial and viscous contributions to forces on swimming animals. This group includes two quantities that are chosen by the researcher: a typical length and speed. Choosing these parameters will affect the numerical value of the Reynolds number, defining the state of the fluid flow. For example: by choosing fish body length as opposed to propulsive fin chord, results may vary by an order of magnitude with consequences for analysis and hydrodynamic regimes. Here we suggest a standardized sets of lengths and speeds to be used for aquatic animal locomotion to enable confident utilization of data from different sources. This framework aims to improve comparative studies within the field.

SEMI-ANALYTICAL APPROACH OF RHEOLOGICAL PROPERTIES OF BLOOD/SILVER–GOLD HYBRID NANOFLUID FLOW IN A CIRCULAR DISK: APPLICATION TO THE HUMAN CIRCULATORY SYSTEMS

This paper examines the three-dimensional flow of a bio-hybrid nanofluid through a porous rotating disk while considering the effects of linear thermal radiation and quadratic thermal radiation and examining entropy generation. The fluid enclosure with blood is taken as base fluid and silver–gold is considered as nanoparticles. The fluid flow phenomenon is characterized by nonlinear coupled differential equations involving two or more independent variables. A suitable numerical technique is used to handle the set of governing equations along with a stability and convergence analysis, followed by applying the homotopy perturbation method for solving stated equations. Through graphical illustrations, the radial and tangential velocity distributions, temperature distributions, entropy production and Bejan number are discussed graphically. The Nusselt number and friction factor results are presented and analyzed. The current finding is validated using the available data in both the numerical and homotopy perturbation methods. The results show that when heat absorption increases on blood/gold–silver hybrid nanofluid, a large heat flux develops on the revolving disk, accelerating the heat-transfer mechanism from that surface in both linear thermal radiation and quadratic thermal radiation cases. Moreover, we have seen that the entropy generation is increasing as the magnetic interaction parameter and heat absorption/generation coefficient in quadratic thermal radiation grow, in comparison with linear thermal radiation. The application of thermal radiation and entropy generation analysis is significantly used in the study of renal artery stenosis (RAS) systems and is an active area of research in the field of biomedical engineering. The model is utilized to compute entropy in physiological systems, such as cancer treatment, heat transfer in tissues, dialysis blood pump, and the efficacy of medical apparatus.

Thermal analysis of Reiner–Philippoff fluid flow with nanoparticles and bioconvection over a radially magnetized curved stretching surface

Thermal analysis of Reiner–Philippoff fluid flow with nanoparticles and bioconvection over a radially magnetized curved stretching surface

Shear Stress and Microbubble‐Mediated Modulation of Endothelial Cell Immunobiology

Cellular immunotherapy remains hindered in the context of solid tumors due to the immunosuppressive microenvironment, in which key endothelial cell adhesion molecules (CAM) are suppressed. Microbubble‐mediated focused ultrasound is being explored for targeted immunotherapy and can exert local shear stress upon neighboring endothelial cells. However, fluid and microbubble‐induced shear modulation of endothelial immunobiology is not well understood. Herein, the influence of both types of shear stress on human endothelial vein (HUVEC) and brain endothelial (HBEC‐5i) CAM expression and secretion of over 90 cytokines using acoustically coupled microscopy is examined. Fluid flow results in time‐dependent modulation of CAM expression, where ICAM‐1 peaked at 4 h (1.98‐fold, p < 0.001, HUVEC) and 24 h (1.56‐fold, p < 0.001, HBEC‐5i). While some chemokines are significantly enhanced (up to 16.2‐fold; p < 0.001) from both endothelial cell types (e.g., IL‐8, MCP‐1, MCP‐3), others are differentially expressed (e.g., CCL5, CXCL‐16, SDF‐1). Under ultrasound, ICAM‐1 expression at 4 h increased (≈1.4‐fold, p < 0.01) and resulted in significant large‐magnitude (p < 0.05) differential expression of 20 cytokines, most of which have immune‐activating function and within a subset of those induced by shear‐flow. Microbubble‐mediated ultrasound regulates ICAM‐1 expression and the human endothelial secretome toward an immune cell recruitment paradigm, and thus may reinforce solid tumor cellular immunotherapy efforts.

The Impact of Fluid Flow on Microbial Growth and Distribution in Food Processing Systems

This article examines the impact of fluid flow dynamics on microbial growth, distribution, and control within food processing systems. Fluid flows, specifically laminar and turbulent flows, significantly influence microbial behaviors, such as biofilm development and microbial adhesion. Laminar flow is highly conducive to biofilm formation and microbial attachment because the flow is smooth and steady. This smooth flow makes it much more difficult to sterilize the surface. Turbulent flow, however, due to its chaotic motion and the shear forces that are present, inhibits microbial growth because it disrupts attachment; however, it also has the potential to contaminate surfaces by dispersing microorganisms. Computational fluid dynamics (CFD) is highlighted as an essential component for food processors to predict fluid movement and enhance numerous fluid-dependent operations, including mixing, cooling, spray drying, and heat transfer. This analysis underscores the significance of fluid dynamics in controlling microbial hazards in food settings, and it discusses some interventions, such as antimicrobial surface treatments and properly designed equipment. Each process step from mixing to cooling, which influences heat transfer and microbial control by ensuring uniform heat distribution and optimizing heat removal, presents unique fluid flow requirements affecting microbial distribution, biofilm formation, and contamination control. Food processors can improve microbial management and enhance product safety by adjusting flow rates, types, and equipment configurations. This article helps provide an understanding of fluid–microbe interactions and offers actionable insights to advance food processing practices, ensuring higher standards of food safety and quality control.

Numerical Analysis of Heat Transfer and Flow Characteristics of Jeffrey Nanofluid Over Stretched Surfaces With MHD and Slip Effects

ABSTRACTThis study employs the Jeffrey fluid model to investigate stress relaxation in non‐Newtonian fluids, offering a more precise representation than conventional viscous models. It explores the influence of multiple slip conditions and magnetohydrodynamics (MHD) on Jeffrey fluid flow and heat transfer across irregular surfaces. Additionally, the impact of thermal radiation and internal heat sources on heat transfer is examined, essential for a comprehensive understanding of the system's thermal dynamics. Using the Buongiorno model, the diffusion and thermophoresis of nanoparticles within the flow are analyzed. Nonlinear coupled governing equations covering flow dynamics, heat transfer, and nanoparticle transport are transformed into ordinary differential equations (ODEs) through similarity transformations and solved numerically using the Runge–Kutta fourth‐order (RK4) method combined with shooting techniques. Results indicate significant effects of physical parameters on temperature, velocity, and mass profiles: a 20% decrease in temperature profiles with an increase in the dimensionless thermal slip coefficient from 0.1 to 0.5 and a 15% reduction in velocity profiles from a 0.1 unit increase in the magnetic parameter . The study also quantifies mass and heat transfer rates to elucidate their impacts. These findings have profound implications for engineering applications involving non‐Newtonian and nanofluids in complex geometrical configurations.

Stability of Weak Electrokinetic Flow

We consider the Nernst-Planck-Stokes system on a bounded domain of Rd, d=2,3 with general nonequilibrium Dirichlet boundary conditions for the ionic concentrations. It is well known that, in a wide range of cases, equilibrium steady state solutions of the system, characterized by zero fluid flow, are asymptotically stable. In these regimes, the existence of a natural dissipative structure is critical in obtaining stability. This structure, in general, breaks down under nonequilibrium conditions, in which case, in the steady state, the fluid flow may be nontrivial. In this short paper, we show that, nonetheless, certain classes of very weak nonequilibrium steady states, with nonzero fluid flow, remain globally asymptotically stable.

Fluid flow impacts endothelial-monocyte interactions in a model of vascular inflammatory fibrosis

The aberrant vascular response associated with tendon injury results in circulating immune cell infiltration and a chronic inflammatory feedback loop leading to poor healing outcomes. Studying this dysregulated tendon repair response in human pathophysiology has been historically challenging due to the reliance on animal models. To address this, our group developed the human tendon-on-a-chip (hToC) to model cellular interactions in the injured tendon microenvironment; however, this model lacked the key element of physiological flow in the vascular compartment. Here, we leveraged the modularity of our platform to create a fluidic hToC that enables the study of circulating immune cell and vascular crosstalk in a tendon injury model. Under physiological shear stress consistent with postcapillary venules, we found a significant increase in the endothelial leukocyte activation marker intercellular adhesion molecule 1 (ICAM-1), as well as enhanced adhesion and transmigration of circulating monocytes across the endothelial barrier. The addition of tissue macrophages to the tendon compartment further increased the degree of circulating monocyte infiltration into the tissue matrix. Our findings demonstrate the importance of adding physiological flow to the human tendon-on-a-chip, and more generally, the significance of flow for modeling immune cell interactions in tissue inflammation and disease.

Construction of the Closed Form Wave Solutions for TFSMCH and (1 1) Dimensional TFDMBBM Equations via the EMSE Technique+

The purpose of this study is to investigate a series of novel exact closed form traveling wave solutions for the TFSMCH equation and (1 + 1) dimensional TFDMBBM equation using the EMSE technique. The considered FONLEEs are used to delineate the characteristic of diffusion in the creation of shapes in liquid beads arising in plasma physics and fluid flow and to estimate the external long waves in nonlinear dispersive media. These equations are also used to characterize various types of waves, such as hydromagnetic waves, acoustic waves, and acoustic gravity waves. Here, we utilize the Caputo-type fractional order derivative to fractionalize the considered FONLEEs. Some trigonometric and hyperbolic trigonometric functions have been used to represent the obtained closed form traveling wave solutions. Furthermore, here, we reveal that the EMSE technique is a suitable, significant, and dominant mathematical tool for finding the exact traveling wave solutions for various FONLEEs in mathematical physics. We draw some 3D, 2D, and contour plots to describe the various wave behaviors and analyze the physical consequence of the attained solutions. Finally, we make a numerical comparison of our obtained solutions and other analogous solutions obtained using various techniques.

Surgery impairs glymphatic activity and cognitive function in aged mice

Delirium is a common complication in elderly surgical patients and is associated with an increased risk of dementia. Although advanced age is a major risk factor, the mechanisms underlying postoperative delirium remain poorly understood. The glymphatic system, a brain-wide network of perivascular pathways, facilitates cerebrospinal fluid (CSF) flow and supports the clearance of metabolic waste. Impairments in glymphatic function have been observed in aging brains and various neurodegenerative conditions. Using in vivo two-photon imaging, we examined the effects of surgery (laparotomy) on glymphatic function in adult (6 months) and aged (18 months) mice 24 h post-surgery. In adult mice, CSF tracer entry into the brain parenchyma along periarteriolar spaces occurred rapidly following intracisternal tracer injection, with no significant differences between sham and surgery groups. In contrast, aged mice exhibited delayed tracer influx, with further impairments observed in the surgery group compared to sham controls. This glymphatic dysfunction correlated with poorer T-maze performance in aged mice. These findings suggest that surgery exacerbates glymphatic impairment in aging brains, potentially hindering brain waste clearance and contributing to postoperative delirium.

A comparative study of casson and Jeffrey nanofluids flowing through the radiative bidirectional stretched surface with porous media

A comparative study of radiative Casson and Jeffrey fluids flows generated by the chemically reactive bidirectional stretched sheet is presented. Energy and mass species analysis is performed under radiative heat generation impacts. The Robin’s heat and mass conditions are imposed for the analysis of considered model. The boundary-driven equations are simplified into one independent variable equation by the implication of similarity constraints. The resulted model is tackled by the help of homotopic scheme. The results of various parameters are sketched and interpreted for both Casson and Jeffrey nanofluids. The convergence is expressed through numeric benchmarks and graphical form. The numeric evaluation of Sherwood and Nusselt number is presented against the versatile parametric values. The results showed that the higher velocity curves appeared in Casson nanofluid case as comparative to case of Jeffrey nanofluid. The temperature heat generation constraints boosted the temperature of both Casson and Jeffrey nanofluids. The incrementing trend of chemical reactive and Lewis number resulted weaker concentration profiles for Jeffrey and Casson fluids. The conducted research model has magnificent appliances in solar energy devices, chemical reactors, solar reservoirs, nuclear power plants, heat reservoirs, microwave oven, thermal radiant, thermal imaging and many others.

Numerical simulations of irreversibility for nonlinearly radiative and chemically reactive flow of Maxwell fluid

The cooling & heating phenomena are involved in numerous engineering-industrial operations and have become essential for the development of thermal electronic & energy devices. In this paper, study is performed on entropy production with an emphasis on nonlinearized thermal radiation and viscous dissipation under the consequence of time dependent magnetic field for an unsteady flow of chemically reactive Maxwell fluid in Darcian porous media. The flow governing equations are solved numerically in MATLAB (bvp4c). Graphs are plotted demonstrating the distribution of irreversibility and entropy generation. Numerical results of the impressions of material parameters on Skin friction, Nusselt and Sherwood numbers are also tabulated. This study establishes that the efficiency of thermal devices can be upgraded by higher order chemical reaction and viscous dissipation effects together with the compressed nonlinear radiation and magnetic effects. Also, unsteadiness in the flow, porosity and magnetic effects enhance the shearing stress on the surface leading to greater surface friction while solar radiation and surface heating due to nonlinearity in radiative force favour the heat transferable rate leading to an improvement in convection rate. These inferences can be helpful in the development of proper thermal electronic and industrial devices with solar radiation applications.