Fluid Flow Control Research Articles

A multilayered homogeneous hydrodynamic cloak realized in a free fluid flow

In recent years, hydrodynamic invisibility cloaks have attracted significant attention from the scientific and engineering communities due to their potential in applications such as fluid flow manipulation, drag reduction, submarine stealth, and biomedical engineering. However, cloaks based on transformation mapping theory typically require porous medium flow, limiting practical implementation. To address this, we draw inspiration from Hele-Shaw flow and develop a homogeneous hydrodynamic cloak composed of multiple layers in free fluid flow at low Reynolds numbers (Re≪1). Through structural optimization, we construct a cloaking shell with ten concentric layers of alternating heights, achieving near-perfect cloaking as demonstrated by simulations and experiments. This non-porous cloak design offers valuable insights into the rapidly advancing field of hydrodynamic metamaterials and enables methods for controlling fluid flow at the microscale, with promising applications in microfluidics.

Neural network-enabled, all-electronic control of non-Newtonian fluid flow.

Real-time, all-electronic control of non-Newtonian fluid flow through a microscale channel is crucial for various applications in manufacturing and healthcare. However, existing methods lack the sensitivity required for accurate measurement and the real-time responsiveness necessary for effective adjustment. Here, we demonstrate an all-electronic system that enables closed-loop, real-time, high-sensitivity control of various waveforms of non-Newtonian fluid flow (0.76 μl min-1) through a micro-sized outlet. Our approach combines a contactless, cuff-like flow sensor with a neural-network control program. This system offers a simple, miniaturized, versatile, yet high-performance solution for non-Newtonian fluid flow control, easily integrated into existing setups.

Viscoelastic dusty fluid Couette flow with heat and mass transfer across a porous oscillating plate in a rotating frame

AbstractThis research aims to enhance industrial processes and address environmental issues by studying the effects of suction and injection on the Couette flow of a viscoelastic dusty fluid over a porous oscillating plate in a rotating frame. We investigate how these factors influence fluid flow, heat, mass, and temperature transfer rates. Suction and blowing are common techniques for controlling fluid flow in conduits. The study considers the impact of the right plate's oscillation on fluid velocity along the x‐axis, as well as mass diffusion and thermal effects from the heating of the right plate. Due to the rotation, the velocities of both the fluid and dust particles exhibit complex primary and secondary behaviors. Also considered the dust particles are homogenously distributed in the base fluid. Furthermore, the variable temperature and concentration are associated with boundary conditions. We develop a mathematical model using partial differential equations (PDEs) to describe these phenomena. The governing equations are non‐dimensionalized and transformed into ordinary differential equations (ODEs) using periodic solutions and solved via the Poincare‐Lighthill perturbation method. Key engineering parameters such as the Sherwood number, Nusselt number, and skin friction are calculated. The study reveals the influence of uniform suction/injection on velocity and temperature distributions, showing that suction can significantly alter boundary layer development, even under resonance conditions. The radiation parameter, Grashof number, and second‐grade parameter cause a decrease in skin friction as their values increase. On the other hand, suction, rotation, magnetic, dusty fluid, and Reynold numbers cause a rise in skin friction.The objective of this research is to improve industrial processes and tackle environmental issues by examining the effects of suction and injection on the Couette flow of a viscoelastic dusty fluid over a porous oscillation plate in a rotating frame. The purpose of this study is to determine how suction/injection influences the Couette flow of a viscoelastic dusty fluid, as well as the heat, mass, and temperature transfer rates across a porous, oscillating plate in a rotating frame. It also takes heat transfer into account. When manipulating the flow of a fluid via a conduit, suction and blowing are common methods. As the right plate oscillates, the x‐axis becomes the primary consideration for fluid velocity. We also take into account the mass diffusion and thermal influence on the flow from the right plate's heating. As a consequence of the spin, the fluid, and dust particles have velocities that are both secondary and primary, making them complicated. Using PDEs, we may translate the aforementioned physical phenomena into a mathematical model of the relevant flow regime. The system of governing equations is non‐dimensionalized by the use of appropriate nondimensional variables. The system of PDEs is transformed into a system of ODEs with the help of assumed periodic solutions and then solved by the perturb solution with the help of Poincare‐Lighthill perturbation methods. We also calculate the Sherwood number, the Nusselt number, and the skin friction, all of which are of relevance to engineers. We also examine how changing these variables affects the velocity distributions of skin friction, viscoelastic fluid, and dust particles. We look at how uniform suction/injection affects the speed and temperature distributions. It is important to note that even in the resonance instance, suction/ injection directs the boundary layer to develop unexpectedly.

Perfusion Bioreactor Conditioning of Small-diameter Plant-based Vascular Grafts.

Vascular grafts are mainly composed of synthetic materials, but are prone to thrombosis and intimal hyperplasia at small diameters. Decellularized plant scaffolds have emerged that provide promising alternatives for tissue engineering. We previously developed robust, endothelialized small-diameter vessels from decellularized leatherleaf viburnum. This is the first study to precondition and analyze plant-based vessels under physiological fluid flow and pressure waveforms. Using decellularized leatherleaf viburnum as tissue-engineered grafts for implantation can have profound impacts on healthcare due to their biocompatibility and cost-effective production. A novel perfusion bioreactor was designed, capable of accurately controlling fluid flow rate and pressure waveforms for preconditioning of small-diameter vascular grafts. A closed-loop system controlled pressure waveforms, mimicking physiological values of 50-120mmHg at a frequency of 8.75Hz for fluid flow reaching 5mL/min. Plant-based vascular grafts were recellularized with endothelial and vascular smooth muscle cells and cultured for up to 3weeks in this bioreactor. Cell density, scaffold structure and mechanics, thrombogenicity, and immunogenicity of grafts were evaluated. Bioreactor treatment with fluid flow significantly increased luminal endothelial cell density, while pressure waveforms reduced thrombus formation and maintained viable vascular smooth muscle cells within inner layers of grafts compared to static controls. Suture retention of grafts met transplantation standards and white cell viability was suitable for vascular remodeling. Low thrombogenicity of endothelialized leatherleaf viburnum holds great potential for vascular repair. This study provides insight into benefits of conditioning plant-based materials with hemodynamic forces at higher frequencies that have not previously been investigated.

Toward Stabilizing the Keyhole in Laser Spot Welding of Aluminum: Numerical Analysis.

The inherent instability of laser welding, particularly keyhole instability, poses significant challenges in industrial applications, leading to defects such as porosities that compromise weld quality. Various forces act on the keyhole and molten pool during laser welding, influencing process stability. These forces are categorized into those promoting keyhole opening and penetration (e.g., recoil pressure) and those promoting keyhole collapse (e.g., surface tension, Darcy's damping forces), increasing instability and defect likelihood. This paper provides a comprehensive instability analysis to uncover key factors affecting keyhole and process instability, presenting future avenues for improving laser welding stability. Using a novel numerical method for simulating laser spot welding on aluminum with COMSOL Multiphysics 5.6, we investigated the effect of laser pulse shaping on keyhole and process instability. Our analysis focused on keyhole morphology, fluid flow behaviour, and force analysis. The results indicated that the curvature effect, Marangoni effect, and Darcy's damping force are primary contributors to instability, with the curvature effect and Darcy's damping force being the most dominant. Additionally, erratic and high-velocity magnitudes induce intense fluid flow behaviour, exacerbating keyhole instability. Moreover, single/quadruple peak triangular and variant rectangular ramp-down pulse shapes produced the least instability, while multi-pulse rectangular shapes exhibited intense instability. It was found that combining triangular/rectangular pulse shapes can reduce force and keyhole instability by smoothing spontaneous force spikes, resulting in a more stabilized welding process. Controlling fluid flow and abrupt force changes with appropriate pulse shaping is key to defect-free welded products.

Scaling up magnetocaloric heat pump for building decarbonization initiatives

Building decarbonization necessitates renewable heating and cooling solutions such as heat pumps. Magnetocaloric heat pumps (MCHP) offer environmental and efficiency advantages but face challenges when scaling up from existing active magnetic regenerator configurations. This study highlights uneven flow resistance, porosity, and refrigerant magnetocaloric effects as key obstacles to MCHP performance in parallel multi-bed setups. To address these effects, two control strategies for the fluid flow control system were investigated: measurement feedback control and model predictive control. Results show a 36.9 % heating power improvement with measurement feedback control, though with extended control convergence times. Model predictive control achieved approximately seven times faster control convergence compared to the measurement feedback control strategy, despite exhibiting minor overshooting. Utilization factor-based model predictive control increased the heating capacity by 1.6 %–30.9 % and the COP by 1.2 %–10.7 % in scenarios with uneven flow resistance and porosity, offering computational efficiency but assuming even magnetocaloric effects between regenerators. This assumption can be addressed by outlet temperature-based model predictive control, albeit at a higher computational cost using genetic algorithm. The findings emphasize the importance of advanced control methods to scaling up MCHP in renewable energy building systems.

Implicit hydromechanical representation of fractures using a continuum approach

Fractures control fluid flow, solute transport, and mechanical deformation in crystalline media. They can be modeled numerically either explicitly or implicitly via an equivalent continuum. The implicit framework implies lower computational cost and complexity. However, upscaling heterogeneous fracture properties for its implicit representation as an equivalent fracture layer remains an open question. In this study, we propose an approach, the Equivalent Fracture Layer (EFL), for the implicit representation of fractures surrounded by low-permeability rock matrix to accurately simulate hydromechanical coupled processes. The approach assimilates fractures as equivalent continua with a manageable scale (≫1 μm) that facilitates spatial discretization, even for large-scale models including multiple fractures. Simulation results demonstrate that a relatively thick equivalent continuum layer (in the order of cm) can represent a fracture (with aperture in the order of μm) and accurately reproduce the hydromechanical behavior (i.e., fluid flow and deformation/stress behavior). There is an upper bound restriction due to the Young's modulus because the equivalent fracture layer should have a lower Young's modulus than that of the surrounding matrix. To validate the approach, we model a hydraulic stimulation carried out at the Bedretto Underground Laboratory for Geosciences and Geoenergies in Switzerland by comparing numerical results against measured data. The method further improves the ability and simplicity of continuum methods to represent fractures in fractured media.

Evaluation of cavitation phenomena in three-way globe valve through computational analysis and visualization test

A three-way valve has a multi-port structure with three openings, which allows control of the fluid direction. However, owing to the complicated trim shape of the internal flow, an irregular fluid flow occurs, which hinders precise fluid flow control. In severe cases, cavitation induces mechanical damage owing to abrupt changes in the fluid direction. In this study conducted a computational fluid dynamics (CFD) analysis was performed to estimate the localized cavitation around the bottom plug of the three-way valve. To quantify localized cavitation, the percentage of cavitation (POC) was derived using the vapor volume fraction (VVF). The POC, defined by the cavitation occurrence zone with VVF > 0.5 divided by the volume of the cavitation danger zone, was 34.90%. Cavitation at this POC level could cause mechanical damage; therefore, a size optimization was performed. The lengths of the optimized waist and tail regions of the bottom plug were obtained wherein the POC level decreased by 19.06%. In addition, experiments were conducted using a flow visualization test setup. The experimental results were quantified into the POC employing the image gradients method, and the results were in good agreement with the CFD analysis.

Fluid flow control around unequal cylinder spacing behind three side-by-side cylinders

Fluid flow control around unequal cylinder spacing behind three side-by-side cylinders

Fracture Characterization Via AI‐Assisted Analysis of Temperature Logs

AbstractFractures control fluid flow, mass transport, and heat transfer in a geothermal reservoir. This makes accurate characterization of fracture networks a prerequisite for optimal design and control of a reservoir's exploitation. We develop a deep‐learning procedure to identify fracture locations via interpretation of temporally and spatially continuous downhole temperature measurements. A long short‐term memory fully convolutional network (LSTM‐FCN) is used both to capture long‐term dependencies in sequential temperature data and to distill local features around fractures. A wellbore and fractured‐reservoir thermal model is established to generate temperature data for network training. The trained LSTM‐FCN exhibits a unique ability to detect multiple fractures intersecting a borehole. We use the LSTM‐FCN algorithm to evaluate the effectiveness of different‐stage wellbore temperature measurements on fracture detection in a complex fractured system. Our experiments reveal that the use of various‐stage temperature information as an input feature set improves the robustness of fracture detection to noise interference. This study indicates the practical feasibility of obtaining accurate fracture‐network reconstructions from temperature signals, at reasonable computational cost.

Non-Enzymatic Detection of Glucose and Ketones in Urine using Paper-Based Analytical Devices

Diabetes, driven by unbalanced diets and unhealthy lifestyles, is highly prevalent. In Indonesia, its prevalence is projected to reach 28.6 million by 2045. Microfluidic paper-based analytical devices (μPADs) are paper-based analytical tools that use hydrophilic paper for measurement and hydrophobic barriers to control fluid flow. This research aims to develop a non-enzymatic method for detecting glucose and ketones in artificial urine using S2Z-μPADs. The fabrication of S2Z-μPADs involves printing the design on Whatman No. 1 paper using wax printing and applying silver nanoparticles for glucose detection and the Schiff base reaction for ketone detection. The results show that the optimum condition for glucose detection is achieved with an AgNO3 concentration of 500 mM. A NaOH concentration of 10 M. Acetoacetate detection is optimized with a glycine concentration of 1 M, sodium nitroprusside concentration of 15%, NaOH concentration of 1 M, a drying time of 8 minutes, and a reaction time of 10 minutes. Validation results demonstrate good linearity for glucose (R² = 0.9821) and ketones (R² = 0.995). High precision was achieved with relative standard deviation (RSD) values of 3.792% for glucose and 1.482% for ketones. The obtained limits of detection (LOD) and limits of quantification (LOQ) indicate that the developed S2Z-μPADs can differentiate between each category of diabetes. The accuracy of glucose and ketone detection ranges from 87.463% to 97.374%. The high accuracy of the μPADs highlights their potential for reliable diabetes management and effective disease monitoring.

Flow control by a hybrid use of machine learning and control theory

PurposeFlow control has a great potential to contribute to a sustainable society through mitigation of environmental burden. However, the high dimensional and nonlinear nature of fluid flows poses challenges in designing efficient control laws using the control theory. This paper aims to propose a hybrid method (i.e. machine learning and control theory) for feedback control of fluid flows, by which the flow is mapped to the latent space in such a way that the linear control theory can be applied therein.Design/methodology/approachThe authors propose a partially nonlinear linear system extraction autoencoder (pn-LEAE), which consists of convolutional neural networks-based autoencoder (CNN-AE) and a custom layer to extract low-dimensional latent dynamics from fluid velocity field data. This pn-LEAE is designed to extract a linear dynamical system so that the modern control theory can easily be applied, while a nonlinear compression is done with the autoencoder (AE) part so that the latent dynamics conform to that linear system. The key technique is to train this pn-LEAE with the ground truths at two consecutive time instants, whereby the AE part retains its capability as the AE, and the weights in the linear dynamical system are trained simultaneously.FindingsThe authors demonstrate the effectiveness of the linear system extracted by the pn-LEAE, as well as the designed control law’s effectiveness for a flow around a circular cylinder at the Reynolds number of ReD = 100. When the control law derived in the latent space was applied to the direct numerical simulation, the lift fluctuations were suppressed over 50%.Originality/valueTo the best of the authors’ knowledge, this is the first attempt using CNN-AE for linearization of fluid flows involving transient development to design a feedback control law.

Finite element method for natural convection flow of Casson hybrid (Al2O3–Cu/water) nanofluid inside H-shaped enclosure

The fundamental problem in electronic cooling systems is the implementation of a cavity such that it can be used to provide localized cooling to specific components, such as CPUs or GPUs, enhancing their performance and longevity. It can also be used in microfluidic devices for controlled drug delivery, where precise control of fluid flow is crucial. The present article numerically explores the free convection non-Newtonian Casson hybrid nanofluid phenomena that occur within an H-shaped cavity while heated from the middle. The heating efficiency and heat flow in a cavity are influenced by perpendicular hot walls that connect two vertical closed channels. A numerical solution is obtained by implementing the Galerkin finite element method to solve the partial differential equation. The numerical outcomes are depicted on the contour of streamlines and isotherms for different parameters in the following ranges: 0.1 ≤ η ≤ 0.4, 0.005≤ϕhp≤0.020, 0.1 ≤ γ ≤ 2, and 103 ≤ Ra ≤ 106 at fixed Pr = 6.2. In addition, line graphs show rate of heat transfer within the enclosure using the average Nusselt number for these parameters. Increased aspect ratios (η = 0.4) result in a minimal rate of heat transfer enhancement, whereas decreasing η leads to a significantly higher average Nusselt number and maximum heat transfer within the cavity. The convective rate of heat transfer increases with the presence of hybrid nanoparticles inside an H-shaped cavity for all Rayleigh numbers. The rotation of the Casson hybrid nanofluid also rises as the volume ratio of nanoparticles increases. For a fixed aspect ratio (A.R) of 0.1, the heat dissipation is 6.91% at a lower ϕhp value of 0.005 at a fixed Ra value of 105. However, it increases to 7.072% for a higher ϕhp value of 0.02 at Ra = 105. With increasing Ra number, ϕhp, and γ, the number NuAve increases.

IoT-Driven Infusion Monitoring & Management System

This research investigates the monitoring and management of an intravenous drip infusion system using the Internet of Things (IoT) and non- contact liquid level sensors, an Arduino circuit board, a GSM interface, and a cloud storage facility. The three sensors in the system are able to detect the presence of fluid without coming into contact with it. They can also send the data they collect to the cloud facility, where it can be used to access drip conditions and monitor fluid levels as well as control infusion flow when needed. This system can be considered an improvement over several systems on the market that are similarly intended to use optical sensors, TDR (Time domain reflectometry), and other types of sensors to monitor the IV drip flow. While it is true that each type of sensor has a combination of benefits and drawbacks, none of the other systems on the market can further regulate the drip flow like this one does. Since the sensors we've employed don't respond to fluids, the patients don't suffer any damage at all. This is now a crucial necessity in the biomedical industry since human reliance on IV drip infusions has led to a number of incidents, the most serious of which involved the patient suffering severe injuries from back blood flow in the nozzle. This system is made to guarantee that all safety precautions are taken and that the patient and attendant are in the best possible circumstances in order to minimize such incidents, accurately monitor and control fluid flow from drip to patients' veins, and prevent back blood flow. Keywords: Internet of Things, Intravenous drip infusion, Non‐contact Liquid Level Sensor, Thing speak, Esp-32, GSM.

A single-particle mechanofluorescent sensor

Monitoring mechanical stresses in microchannels is challenging. Herein, we report the development of a mechanofluorescence sensor system featuring a fluorogenic single polydiacetylene (PDA) particle, fabricated using a co-flow microfluidic method. We construct a stenotic vessel-mimicking capillary channel, in which the hydrodynamically captured PDA particle is subjected to controlled fluid flows. Fluorescence responses of the PDA particle are directly monitored in real time using fluorescent microscopy. The PDA particle displays significant nonlinear fluorescence emissions influenced by fluid viscosity and the presence of nanoparticles and biomolecules in the fluid. This nonlinear response is likely attributed to the torsion energy along the PDA’s main chain backbone. Computational fluid dynamic simulations indicate that the complete blue-to-red transition necessitates ~307 μJ, aligning with prior research. We believe this study offers a unique advantage for simulating specific problematic regions of the human body in an in vitro environment, potentially paving the way for future exploration of difficult-to-access areas within the body.

Influence of oscillatory hydromagnetic field with mixed convection driven Sutterby nanofluid flow over a stretching cylinder

A nonlinear mixed convective sutterby nanofluid flow along a stretching cylinder is being studied in this article. The set of partial differential equations (PDEs) that control fluid flow is nonlinear and subject to surface constraints and similarity transformation reduces a system of PDEs to non-dimensional ordinary differential equations (ODEs), which are then solved in MATLAB Bvp5c solver which is based on the Runge–Kutta method and Shooting technique. We provide a graphic evaluation of the significant contributions made by the various physical terms to engineering measurements in the curiosity and transport domains. The study discovers that temperature distribution increases heat border viscosity but reduces thermal diffusion, whereas nonlinear convection heat improves surface heat transfer. The periodic magnetic field raises the fluid temperature while decreasing the rate of energy transfer. Furthermore, experiments have demonstrated that oscillating magnetic fields induce fluctuations with a sinusoidal pattern. Furthermore, the current study has applications in the design and manufacture of cylinder-shaped objects in various fields such as aerospace engineering, geophysics, and nuclear engineering. These include core catchers in nuclear power plant steam turbines, waxy crude oils or foodstuffs in centrifugal pumps, and deformation rates that frequently occur in practical turbomachinery and other industrial processes.

Characteristics of the Fault Damage Zone From High‐Resolution Seismic Imaging Along the Palos Verdes Fault, California

AbstractThe distribution and intensity of fault damage zones provides insight into fault activity and its relationship to fluid flow in the crust. Presently, measures of the in‐situ distribution of fault damage remain limited and along‐strike studies are rare. This study focuses on an offshore section Palos Verdes Fault damage zone that spans 28 km, near Los Angeles, California. To investigate the previously unresolved shallow (∼400 m below the seafloor) fault damage zone we use densely spaced (∼500 m line separation) newly collected sparker multichannel seismic lines and sub‐bottom profiles. The combination of high‐resolution acquisition methods and specialized seismic processing workflows provide improved imaging of shallow faulting. We apply a multi‐trace similarity technique to identify discontinuities in the seismic data that may be attributed to faults and fractures. This fault detection approach reveals diverse fault damage patterns on adjacent seismic profiles. However, a discernible damage zone pattern emerges by stacking multiple damage detection profiles along strike. We find that peak damage identified in this way corresponds to the active main fault strand, confirmed in this study, and thus the technique may be useful for identifying active fault strands elsewhere. Additionally, we observe that the variable width of the damage zone along strike is controlled by fault obliquity. Furthermore, our observations reveal a correlation between fault damage and seafloor fluid seeps visible in the water column, suggesting that damage plays a role in controlling fluid flow around the fault.

Experimental and Theoretical Study of a Novel Hydraulic Fluid Flow Control Method

Experimental and Theoretical Study of a Novel Hydraulic Fluid Flow Control Method

Controlled Fluid Flow Without Controlling Pump Through Arduino

Various Industries like Chemical, Energy, Nuclear, Process, Manufacturing, Healthcare, and Agriculture require the flow rate to be controlled. It may be constant, steady state, or between the specific upper and lower range. The article explained the development of a cost-effective fluid flow control system using an Arduino microcontroller. The direct use of the pump is not good because there are a lot of challenges (Corrosion, Power fluctuations, Pressure leak) with the pump and with time as it gets old, the chances of getting good, desired flow from it are not possible. We achieved the controlled flow rate (volume rate and mass rate) in a very precise and cost-effective manner. Because the flow corresponding to the height is steadier and more constant than getting steady flow from the pump. Hence, our solution is that we don’t get direct flow from the pump but from Tank B. Tank B must be very carefully designed (especially its height and cross section) to get the desired value of the flow rate from it, as per Bernoulli’s Theorem the flow velocity has a direct relation with the height. We just used the pump to refill tank B up to the desired level. In this case, the flow rate only varies when there is a larger change in the head of the tank from which it is coming (It is tank B in our case). The pump automatically becomes ON when the flow rate drops below 2 and fills tank B again to the height which corresponds to the flow rate 3 and when the flow rate becomes 3 the pump becomes OFF automatically. The process is repeated until the desired process is completed. After Completion the valve from Tank B can be closed. The Hardware integrations, Software Programming Logic, and Physical experimental setup are discussed.

Study of Orifice Design on Oleo-Pneumatic Shock Absorber

Aircraft oil-strut shock absorbers rely on orifice designs to control fluid flow and optimize damping performance. However, the complex nature of cavitating flows poses significant challenges in predicting the influence of orifice geometry on energy dissipation and system reliability. This study presents a comprehensive computational fluid dynamics (CFD) analysis of the effects of circular, rectangular, semicircular, and cutback orifice profiles on the internal flow characteristics and damping behavior of oleo-pneumatic shock absorbers. High-fidelity simulations reveal that the rectangular orifice generates higher damping pressures and velocity magnitude than those generated by others designs, while the semicircular shape reduces cavitation inception and exhibits a more gradual pressure recovery. Furthermore, the study highlights the importance of considering both geometric and thermodynamic factors in the design and analysis of cavitating flow systems, as liquid properties and vapor pressure significantly impact bubble growth and collapse behavior. Increasing the orifice length had a negligible impact on damping but moderately raised orifice velocities. This research provides valuable insights for optimizing shock absorber performance across a range of operating conditions, ultimately enhancing vehicle safety and passenger comfort.