Interaction Of Fluid Flow Research Articles

Review of Magnetization Impacts on Vapor Absorption Refrigeration Systems

Amidst the ongoing maintainable energy revolution, reducing energy consumption in vapor absorption refrigeration system (VARS) has become a critical application part. Over the past several decades, extensive research has been devoted to these systems. This study presents a thorough classification and review of the existing literature on magnetized refrigeration systems, specifically focusing on VARS. The paper explores the effects of magnetic fields on fluid flow interactions, categorizing the research into Electro-Hydrodynamics (EHD) and Magneto-Hydrodynamics (MHD). It highlights the distinctive impacts of magnetic fields on the thermophysical properties of electrically conducting fluids. Additionally, the article delves into the fundamental mechanisms behind the influence of magnetization on these properties. The review encompasses experimental studies conducted over the last two decades regarding the effects of magnetization on VARS.

Flowing Liquid Crystal Torons Around Obstacles

Liquid crystal torons, localized topological structures, are known for their stability and dynamic behaviour in response to external stimuli, making them attractive for advanced material applications. In this study, we investigate the flow of torons in chiral nematic liquid crystals around obstacles. We simulate the fluid flow and director field interactions using a hybrid numerical method combining lattice Boltzmann and finite difference techniques. Our results reveal that the toron dynamical behaviour depends strongly on the impact parameter from the obstacle. At impact parameters smaller than half cholesteric pitch, the flowing toron is destabilized by the interaction with the obstacle; otherwise, the flowing toron follows a trajectory with a deflection which decays exponentially with the impact parameter. Additionally, we explore the scattering of torons by multiple obstacles, providing insights into how the dynamics of these structures respond to complex environments.

Nonlinear model of interaction of unsteady fluid flow with structure in hydraulic systems of aircraft and helicopters

Nonlinear model of interaction of unsteady fluid flow with structure in hydraulic systems of aircraft and helicopters

Algorithm for the treatment of boundary conditions in NMM-SPH coupling models: Interface element-wise boundary particle scheme

Large deformation and complex fluid flow interactions, known as the fluid–structure interaction (FSI), are common in geotechnical and coastal projects. To address FSI problems involving crack development, block contact and large movement, a numerical model that utilises smoothed particle hydrodynamics for fluid field spatial discretisation and numerical manifold method for solid block domain solution is proposed in the present study. Specifically, to restore the particle inconsistency near the interface and the overflow issue around the sharp corner in traditional coupled methods, a recommended boundary particle approach is designed to provide full support for particles near the interface, regardless of the interface’s geometry. Moreover, this approach enables the choice of different spatial resolutions tailored to requirements of solid and fluid domains. Six numerical examples were conducted to verify the reliability, accuracy and robustness of the new method. Results showed that relative errors around the sharp corner are lower than those in previous studies. Furthermore, the new model performs well in dealing with the motion of blocks with arbitrary shapes, including large movements, block contacts, crack propagations, and large deformations. Additionally, various inner-variable field evolutions between fluids and solids were visualised, which is beneficial for the prediction of multi-hazard scenario outcomes.

A coupled FD-SPH method for shock-structure interaction and dynamic fracture propagation modeling

Shock wave propagation and their damage to solid structures, which involve complex multiphase and multiphysics phenomena, are difficult problems to address. In this paper, a three-dimensional graphics processing unit (GPU)-accelerated finite difference-smoothed particle hydrodynamics (FD-SPH) method was developed for the prediction of strongly compressible fluid flow and strong fluid-structure interactions. The conventional mesh-based finite difference method was used to simulate shock wave propagation, while the smoothed particle hydrodynamics method was employed to predict the dynamic behavior of solid materials. In addition, the immersed boundary method (IBM) was implemented in the GPU-accelerated FD-SPH solver for the boundary treatment of the interface between solid and fluid materials. Four numerical cases, namely shock-cylinder obstacle interaction, elastic panel deformation induced by shock wave propagation, the response of stainless steel tubes under internal blast loading, and the damage of blast loading on reinforced concrete slab, were conducted for verification of the GPU-accelerated FD-SPH solver. The numerical results were compared against the available experimental data, which shows that the GPU-accelerated FD-SPH solver is capable of capturing the shock wave propagation and its damage to structures very well.

Abstract PO5-25-02: Microenvironment based co-culture dependence of breast cancer and immune cell interactions on functional outcomes

Abstract The tumour microenvironment (TME) includes physical forces from interstitial fluid flow and cell-cell interactions that modulate cancer development and progression through activation of multiple oncogenic pathways leading to tumor growth and metastatic spreading. We previously reported on the role of physical forces on epithelial to mesenchymal transition (EMT) and S100 gene family expression and cell to cell adhesion properties with implications to normal breast development and cancer. Signals from the tumor exit the local tumor environment through interstitial fluid transport and cell migration where they can be found in the blood stream. We developed a whole blood RNA gene expression biomarker panel coupled with proprietary software capable of identifying the presence of an active breast cancer signature at early stages of disease with clinical study results previously reported. Here we report on results from transcriptomic and function studies with cell interaction models. Cancer cells can influence immune cells through direct contact or via secreted molecules causing the immune cells to undergo functional changes. To investigate mechanisms involved in the induction of these alterations in a model system, we performed co-culture studies with human monocytic cells and breast cancer cells. Interaction of human monocytic cells with the breast cancer cells caused significant changes in both behavior and transcriptomes. Moreover, using RNAseq and pathway analysis we demonstrated that the changes induced through the exposure to the more aggressive triple negative (TNBC) phenotype were distinct from the alterations triggered upon contact with an ER+ breast cancer cell line. We also show that cancer-immune crosstalk triggers EMT as well as activation of multiple oncogenic pathways associated with cell migration and invasion, cell chemotaxis and cell-to-cell interactions. As the interplay between cancer and immune cells plays an important role in cancer progression, these findings provide important insight into key mechanisms controlling these outcomes. Citation Format: Karen Norek, Jacob Kennard, Kenneth Fuh, Robert Shepherd, Kristina Rinker, Olesya Kharenko. Microenvironment based co-culture dependence of breast cancer and immune cell interactions on functional outcomes [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO5-25-02.

Improving Aeromechanical Performance of Compressor Rotor Blisk with Topology Optimization

When it comes to modern design of turbomachinery, one of the most critical objectives is to achieve higher efficiency and performance by reducing weight, fuel consumption, and noise emissions. This implies the need for reducing the mass and number of the components, by designing thinner, lighter, and more loaded blades. These choices may lead to mechanical issues caused by the fluid–structure interaction, such as flutter and forced response. Due to the periodic aerodynamic loading in rotating components, preventing or predicting resonances is essential to avoid or limit the dangerous vibration of the blades; thus, simulation methods are crucial to study such conditions during the machine design. The purpose of this paper is to assess a numerical approach based on a topology optimization method for the innovative design of a compressor rotor. A fluid-structural optimization process has been applied to a rotor blisk which belongs to a one-and-a-half-stage aeronautical compressor including static and dynamic loads coming from blade rotation and fluid flow interaction. The fluid forcing is computed by some CFD TRAF code, and it is processed via time and space discrete Fourier transform to extract the pressure fluctuation components in a cyclic-symmetry environment. Finally, a topological optimization of the disk is performed, and the encouraging results are presented and discussed. The remarkable mass reduction in the component (≈32%), the mode-shape frequency shift from a fluid forcing frequency, and an overall relevant reduction in the dynamic response around Campbell’s crossing confirm the efficacy of the presented methodology.

Numerical Solution of Darcy-Forchheimer Casson Nanofluid Flows with Joule Heating and Radiation

The present article provides a description of the hydrothermal properties of a Non –Newtonian nanofluid flow over a Darcy surface that is undergoing extension. The Darcy-Forchheimer effect is a phenomenon that describes the movement of nanofluids through a variable surface. The present study aims to investigate the impact of thermal radiation on heat transfer in magnetohydrodynamic (MHD) flow, utilizing a Casson nanofluid. The impacts of chemical reaction, magnetic field and thermal radiation are taken into consideration. The flow equations are transformed to ordinary differential equations by the appropriate similarity transformations. The Keller-Box method is used to compute the governing differential equations. It is found that the angle of inclination parameter enhances the thermal boundary layer thickness of the flow and the Joule heating parameter improves the thermal boundary layer thickness and slows the fluid velocity, which helps to maintain system temperature. The rate of Heat is increasing while mass transfer rate decreasing with the increasing values Brownian motion. Numerical and graphical results of various flow parameters as well as heat and mass rates are also provided in tables and graphs. So, the observation of the results systems for electronic devices, where the interaction of fluid flow, heat transfer, and electromagnetic effects is significant.

Applicability of Dynamic, Local, and Diffusive Wave Models for Unified Depth-Averaged Fluid Flow Interaction with Porous Media

Applicability of Dynamic, Local, and Diffusive Wave Models for Unified Depth-Averaged Fluid Flow Interaction with Porous Media

An enhanced moving particle semi-implicit method for simulation of incompressible fluid flow and fluid-structure interaction

An enhanced moving particle semi-implicit method for simulation of incompressible fluid flow and fluid-structure interaction

Computational modeling of a thread-based microfluidic fuel cell with carbon fiber electrodes

Thread-based microfluidic fuel cells are promising micro power sources for portable and wearable electronic devices. In this study, a three-dimensional computational model is developed for a thread-based microfluidic fuel cell with carbon fiber electrodes. The interaction of fluid flow, species transport and electrochemical reactions is elucidated. The cell polarization curve obtained from modeling is validated by the experimental data. Moreover, effects of operational parameters and structural parameters on the cell performance and mass transport are further investigated. Results demonstrate that the presence of the intermediate flow channel can effectively prevent the reactant crossover and the parasitic current density is negligible. Appropriate increase in the reactant concentration is beneficial to yield uniform concentration distribution and enhance the mass transfer. Besides, the peak power density is only increased by 0.7% when the flow rate of anolyte and catholyte is increased by four times. Additionally, lowering the electrode spacing and the electrode porosity result in the superior cell performance. With the electrode spacing of 3 mm and the electrode porosity of 0.6, the peak power density of 34.6 mW cm−2 and the maximum current density of 112.5 mA cm−2 are achieved. This work provides theoretical guidance for future development and optimization for thread-based microfluidic fuel cells.

The impact of bio-inspired micro-textures on turbulence and implications for bio-fouling settlement

Biomimetic textures originally developed as an anti-fouling strategy for static immersion, have been studied for application on marine hydro-turbines. Turbulent flow Simulations have been performed to characterize hydrodynamic stresses in area where micro-organisms are expected to settle. The study relies on Large Eddy Simulations of fully developed channel flow in the transitionally rough regime to study the fluid flow interaction around the texture prisms. The analysis focusses on the sensitivity to the texture layout and orientation and considers three different gap sizes S+=10,40,80, scaled in inner units, where the smallest gap S+=10 corresponds to the physical gap between textures at full scale when applied over a turbine blade operating under nominal conditions. Results indicate that the smallest gap which has been shown previously to be most effective at hindering micro-organism attachment also creates an effective shelter against mean turbulent stresses. Interestingly, however, strong infrequent turbulent fluctuations are predicted within the gap. These may be sufficient to avoid unwanted accumulation of the smallest organisms and passive particles. Exposed surfaces including within groves between textures, where organisms would be most expected to settle in static immersions, are also found to experience significant stresses as the gap size is increased.

A spheropolyhedral-based discrete element lattice Boltzmann method for simulation of non-spherical adhesive particulate flow

Non-spherical particulate flow is commonly encountered in nature, industry and our daily life. But up to now, there still lack effective model to describe the adhesive elastic collision between non-spherical microparticles. To solve this problem, a spheropolyhedral-based discrete element method (DEM) combined with Johnson-Kendall-Roberts (JKR) model is proposed. The contact between non-spherical particles is attributed to the contacts between three geometry features, including vertice-vertice (V-V), vertice-edge(V-E), vertice-face (V-F) and edge-edge (E-E). The JKR adhesive model is modified to calculate the contact force of the contacting geometry features based on the actual contact area. Meanwhile, the lattice Boltzmann coupled with the immersed moving boundary (LB-IMB) method is employed to simulate the fluid flow and fluid-particle interaction. The novel spheropolyhedral-based DE-LBM is verified to be accurate and effective by several experiments and the data in references. Finally, an application test for simulating the packing process of non-spherical microparticles is presented. The method well predicts the packing structure of both adhesive and non-adhesive non-spherical particles, meaning that it can be easily extended to simulate the massive non-spherical microparticles with high effectiveness and efficiency. Program summaryProgram Title: adhesive contact force model for non-spherical particleCPC Library link to program files:https://doi.org/10.17632/vswvv7ppz2.1Developer's repository link:https://github.com/QIAN-C/adhesive-force-model-for-non-sphericalLicensing provisions: GNU General Public License v3Programming language: C++Nature of problem: Various methods have been proposed to handle the complex shapes of non-spherical particles in the discrete element method. However, there is still a lack of effective models for calculating the contact force between the non-spherical fine particles, particularly the adhesive forces.Solution method: Based on the sphere-polygon algorithm and the JKR model, this program has developed a contact force model that can accurately calculate adhesive forces between non-spherical fine particles within the framework of the open source library MechSys (URL: http://mechsys.nongnu.org/index.shtml).

Numerical performance investigation of a photovoltaic-thermal hybrid collector-evaporator with different tube configurations for heat pumps

Surface temperature build-up due to the continuous conversion of incident sunlight to heat deteriorates the power output, efficiency, and life of photovoltaic panels. Photovoltaic-thermal (PV-T) systems provide a potential solution to avoid excessive heating of PV panels, simultaneously providing useful heat energy. A heat extraction unit is attached to the PV panel in PV-T systems that extract and convert the waste heat into useful heat. Therefore, design and material selection are keys to better performance in the system-level approach. Additionally, it is a cumbersome task dealing with refrigerant-based heat and fluid flow interactions in a system-level approach. With this in perspective, this paper analyzes different materials and flow configurations of PV-T systems. A transient, three-dimensional turbulence solver coupled with heat transfer through solids and liquids physics is modeled using COMSOL Multiphysics software. R-32 refrigerant acts as the heat transfer fluid in the system loop. The conservation equations are discretized using the finite element method. The present study involves two different plate materials (aluminum and copper) and three flow configurations (serpentine, roll-bond, and spiral) with and without absorber plates. A total of eight different configurations are being investigated here. The obtained results suggest that with the absorber plate, the performance increases significantly with a PV panel temperature decrease of 4–5 K, and the outlet fluid temperature increase by 2–8 K. It was observed that the performance difference between copper and aluminum plate is minimal (2%). Roll-bond flow configuration has scope for further research since it is more efficient than others because of the larger contact area for heat transfer.

Direct and Inverse Problems of Dynamics of Surface Waves Caused by Flow around Underwater Obstacle

The paper presents algorithms and results of calculations of the dynamics of the surface layer of a liquid under the action of currents that have emerged from the depth. Several approaches to modeling the velocity field in a horizontal flow round a fixed underwater obstacle are investigated. Formulas for calculating the velocity field on the free surface of an ideal homogeneous liquid are proposed. A computer program has been developed that makes it possible to simulate the interaction of a stratified fluid flow with an underwater obstacle. The possibility of using asymptotic formulas for the far-field approximation to calculate the velocity field in a uniformly stratified fluid is studied.

Sonodynamic Bacterial Inactivation Enhanced by an Actuator‐Integrated Mechanism

AbstractSonodynamic bacterial inactivation, a reactive oxygen species (ROS)‐empowered approach featuring high penetration depth and low health risk, is explored for antibiotic‐free antibacterial treatment. However, the low yield and insufficient diffusion of ROS negatively affect the antibacterial efficacy of sonodynamic treatment, thus hindering its further development. Here an actuator‐integrated mechanism is proposed for enhancing the sonodynamic efficacy of loaded sonosensitizers through motion‐induced hydrodynamic effects, demonstrated by a porphyrin‐decorated gold nanomotor, which can produce ROS for bacterial inactivation while performing multimodal motion via actuation using low‐frequency ultrasound. Corroborated by numerical simulation, the experimental results show that the motor's stirring motion significantly increases the yield and diffusion of ROS through fluid flow and frequent interactions between the motor and bacterial targets, resulting in doubled antibacterial efficiency in comparison to a stationary motor. Furthermore, the flow‐induced shear forces combined with the frequent interactions constitute a source of mechanical damage and can form a synergy with the antibacterial properties of ROS, enabling an efficient biofilm eradication that is inaccessible by freely suspended porphyrin. In conclusion, this study reports a motion‐based strategy to enhance sonodynamic efficacy and provides proof of concept using a sonodynamic gold nanomotor powered by ultrasound.

Three-Phase Fluid Flow Interaction at Pore Scale during Water- and Surfactant-Alternating Gas (WAG/SAG) Injection Using Carbon Dioxide for Geo-Sequestration and Enhanced Oil Recovery

Sequestration of CO2 in geologic formations such as depleted oil reservoirs has emerged as one of the lead solutions to tackle greenhouse gas emissions to reduce pollution and global warming. Supercritical CO2 (sc-CO2) injection in oil reservoirs has proven to be useful as an enhanced oil recovery (EOR) technique along with the benefits of CO2 sequestration. In this study, a tortuous microscopic pore scale model was used to study and investigate the phenomena of water-alternating gas (WAG) and surfactant-alternating gas (SAG) with sc-CO2. The study scrutinizes the dynamics of the pore-level phenomenon in the multiphase WAG and SAG flows at the pore level in detail. Transient computational fluid dynamics (CFD) analysis was used to study the fluid flow characteristics of oil, water, and sc-CO2 at different reservoir pressure and temperature conditions in oil-wet conditions. Governing equations were coupled with EOS (Helmholtz free energy equation) to capture the viscous and intrinsic properties of sc-CO2 due to variations in pressure and temperature conditions. It was found that higher oil recovery does not necessarily indicate higher sc-CO2 sequestration and that temperature harms the displacement mechanism due to unfavorable mobility ratios. Comparing WAG and SAG for the first injection cycle, SAG showed a more diffused interface between displaced and displacing fluid. The additional oil recovery produced in patches was a result of pressure oscillations near the blind pores. Moreover, high vorticity promotes greater intermixing between the displacing and displaced fluid by increasing the rate of interface length. In SAG cases, faster sc-CO2 breakthroughs were observed due to reduced shear stress along the fluid interfaces, which resulted in higher sequestration values in a given time frame. The CO2 sequestration volume in SAG cases was found to be approximately 40% more than in WAG experiments. The study confirms that lower values of oil–water interfacial tension aids in faster and more efficient sequestration of sc-CO2 along with additional oil gain from a given reservoir.

Numerical simulation and experimental studies on acoustofluidic separation of microparticles using 3D printed chips

Principles of acoustofluidics can be used to manipulate and separate microparticles and cells in microchannels. In this study using numerical simulations, we will be investigating the limits of fundamental assumptions used in acoustofluidic such as a limited acoustic scattered field or fluid flow interaction between the particles/cells. A device-level numerical simulation tool will be used which accounts for the effect of the piezoelectric materials, interactions between the microparticles/cells fluid flow-field and the acoustic-field in the microchannel. Also, in this study, different numerical acoustic and mechanical models of biological cells will be investigated and the conditions (frequency, channel dimensions, etc.), which favor the acoustofluidic separation of cells with similar mechanical properties will be studied numerically. Finally, the results of the numerical simulations will be utilized, and experimental studies will be demonstrated, which separate microparticles/cells in a 3D printed polymeric chip.

Archean Pb isotope variability tracks crust-mantle fractionation, granite production, and ore deposit formation

Various geological processes that affect Earth's crust may be encoded into isotopic tracers preserved in rocks and minerals. The enhanced sensitivity of U, Th, and Pb to crustal fractionation processes allows Pb isotopes to complement information from the Nd and Hf isotope systems. However, melt fractionation, crustal contamination and recycling, hydrothermal fluid flow and fluid-rock interaction, and other processes in the continental crust can lead to mixing of Pb isotopic signatures. Here, we report new Pb isotopic data from granite-K-feldspar and integrate these data with published Pb isotope ratios from granite K-feldspar and Pb-rich ores across the Yilgarn Craton in Western Australia. The aim of this study is to explore how the variability of Pb isotope ratios and derivative parameters can be used to gain information on specific geological processes occurring throughout the crustal column. We develop a model that subdivides different sampling media into chemical process groups and links their initial Pb signatures to Pb source regions and fractionation processes at various locations within the crust and upper mantle. Equilibration of Pb signatures with a primary mantle source reservoir (in part represented by volcanic-hosted massive sulfides) is contrasted with granite formation in the mid to lower crust (granite K-feldspar), and mineralization of ore deposits in the mid to upper crust (Pb-rich ores). Spatial trends similar to those in Nd and Hf isotopic data are recorded by Pb isotopic derivative parameters (μ = source 238U/204Pb, ω = 232Th/204Pb, and Δt - the difference between true sample age and Pb model age) calculated for komatiite-hosted Ni sulfide ores, granite K-feldspar, and volcanic-hosted massive sulfide (VHMS) ores. The significance of subtle differences in absolute values of derivative parameters is supported by the diversity of Pb isotope ratios, Pb model ages, and ∆t as tracked by a statistical metric, quantifying the variability of Pb sources involved in the formation of different chemical process groups. Generally greater variety in an older terrane (Youanmi) documents more ancient and recycled continental crust as compared with more homogeneous Pb isotopic signatures in a younger terrane (Eastern Goldfields Superterrane). The Pb signatures are interpreted, in part, to relate to the timing of source fractionation in the upper mantle with a legacy of this source signal preserved through various depths in the lithospheric section. The least radiogenic VHMS ore samples appear to provide a good approximation of mantle Pb signatures, indicated for example by a deficit in 206Pb and 208Pb relative to the other process groups. A significant heterogeneity recorded in Pb isotopic data from Pb-rich gold ores is explained by the interplay of hydrothermal fluids with diverse sources leading to the mineralization of gold deposits (e.g., leaching of Pb from surrounding rocks or fluid mixing). Such gold ore Pb signatures are distinct from other process groups, which together track sources less heterogeneous in age and/or U and Th.

Aerodynamic Optimization of Trailing-Edge-Serrations for a Wind Turbine Blade Using Taguchi Modified Additive Model

For the rotor, achieving relatively high aerodynamic performance in specific wind conditions is a long-term goal. Inspired by the remarkable flight characteristics of owls, an optimal trailing edge serration design is investigated and proposed for a wind turbine rotor blade. Fluid flow interaction with the proposed serrations is explored for different wind conditions. The result is supported by subsequent validation with three-dimensional numerical tools. The present work employs a statistical-numerical method to predict and optimize the shape of the serrations for maximum aerodynamic improvement. The optimal combination is found using the Taguchi method with three factors: Amplitude, wavelength, and serration thickness. The viability of the solution on an application is assessed using the Weibull distribution of wind in three selected regions. Results show that the presence of serration is capable of improving the annual power generation in all the investigated cities by up to 12%. The rated speed is also shifted from 10 m/s to 8 m/s for most configurations. Additionally, all configurations show similar trends for the instantaneous torque, where an increase is observed in pre-rated speed, whereas a decrease is noticed in the post-rated speed region. A look at the flow field pattern for the optimal design in comparison with the clean blade shows that the modified blade is able to generate more lift in the pre-stall region, while for the post-stall region, early separation and increased wake dominate the flow.