Computational Fluid Dynamics (CFD) modelling and simulation

In garment-making industries, workers have to work for more than eight hours continually either by sitting or by standing in one position. Therefore, stress is developed in their bodies, which might lead to musculoskeletal disorders (MSDs). The purposed of this paper is to explain the design and simulation of an ergonomic sewing chair workstation for workers at garments manufacturing, Rivatex East Africa Limited (REAL), Eldoret, Kenya. The SOLIDWORKS 2023 software (design and simulation tool), was used to develop an ergonomic design of the sewing chair workstation based on the worker's anthropometric data. The model of an ergonomically sewing chair was simulated using SOLIDWORKS software based on Finite Element Analysis (FEA) test with a deformation scale of 30,050.2 to check its ability to withstand the weight of the human body. The loads applied were 800 N on the base seat and 150 N on the backrest of the seat. The aluminium alloy 1060 was selected for FEA test with a yield strength of 2.757e + 01 N/mm 2 and tensile strength of 6.893e + 01 N/mm 2. The FEA criteria included stress, displacement, strain and Factor of Safety (FOS). The FEA results showed that the aluminium model passed the test satisfactorily, due to the many criteria: the maximum stress is 7.175e-01 N/mm 2 and does not exceed the yield strength of the material, which was acceptable; the maximum displacement was 3.209e-03 mm, thus, the maximum deformation becomes 0.03209 mm, which was below the assigned safety level; the maximum strain established from the results was 6.258e-06 which was can be considered within the range for the material, which meant that the model would not break or fail due the applied loads. It was also established from the results that there was a minimum FOS distribution value of 3 from the model analysis. This implied that the model needs 3 times of loads applied to deform the selected material, which could be considered within the range safety limits. This research study can be extended by fabricating and manufacturing the proposed sewing chair model and validating the sewing chair design by experimental study.

Utilizing newly developed instruments, it is now possible to directly measure both the precise location and absolute intensity of a vortex field emitted from a magnetotelluric anomaly. Tracking the magnetotelluric anomalies through the landscape offers new opportunities for analyzing the aetiology of these phenomenons, while newly developed instruments allow objective and fully quantifiable measurements of the effectiveness of methodologies implemented for active mitigation.

A two phase Smoothed Particle Hydrodynamics method is developed to simulate the violent deformation of the free surface and the formation of the cavity induced by the two dimensional wedge entering water. The flow field of water and air are computed simultaneously. A non-reflection boundary treatment for SPH method is proposed to remove reflection of pressure wave against the solid boundaries of computational domain. The water jet generated at the early stage of water entry and the cavity induced by the free surface sealing are reproduced for the case of the vertical water entry of a wedge. The computational pressure distribution and the velocity field can be obtained. Numerical results agree well with the experimental data in literature to verify the two phase SPH method and the boundary treatment approach. It turns out that the cavity evolves with significant deformation of the cavity surface.

A microbial colony is a visible cluster of microorganisms growing on the surface of or within a solid medium. This may be from a single cell or an amalgam of the same organism of more than one cell or a mix of different organisms. Bioburden levels are commonly measured when conventional methods are deployed in terms of colony-forming units (CFUs). These units provide an estimation of the number of viable bacteria or fungal cells found on a sample, expressed against a unit of measurement, such as per millilitre or per milligram.

When counting CFUs on solid microbiological culture media (agar) there are some aspects of ‘counting’ that need to be considered. These are:

a) Rounding and averaging

b) Significant figures

c) Countable range

d) Statistical error from low counts


This article looks at each of these aspects of the microbial plate count.

Sandle, T. (2025) Means, Ranges and Replicates: Improving Microbial Plate Counting, European Journal of Parenteral and Pharmaceutical Sciences, 30 (1): https://www.ejpps.online/post/means-ranges-and-replicates-improving-microbial-plate-counting

La forma tradicional de estructurar la sesión de actividad física para mayores (calentamiento, parte principal y vuelta a la calma), nos ha generado la necesidad de reflexionar e investigar sobre la adecuación de dicha estructura a las finalidades que perseguimos en este tipo de programas. A partir del estudio realizado, proponemos un nuevo diseño de sesión, adaptado a los intereses y necesidades de los participantes, planteando diferentes subfases o modalidades en las que incluir contenidos fundamentales para el desarrollo óptimo de programas de actividad física saludable. Para ello, es fundamental analizar las finalidades, posibilidades y dificultades que tiene el desarrollo de un programa de actividad física para mayores, con el objetivo de construir un modelo didáctico acorde con sus necesidades.

The paper presents the review of methods for determining hydrogeological properties of rock mass in the place of mine shaft location. The largest Polish copper ore deposit is located in the Fore-Sudetic Monocline. It is the Kupferschiefer-type deposit occurring at a depth of 400 to 1200 metres. During the last 60 years the deposit was opened with 30 mine shafts, and the 31st shaft is currently being sunk. The methods of hydrogeological tests in boreholes as well as the methods of estimation of hydrogeological parameters and prediction of water inflow into the sinking mine shaft have evolved through the years. In the 1960s, the most popular field test was the well bailing/infiltration test, and the most popular methods of parameters estimation and inflow prognosis were analytical equations and analytical methods of water inflow forecasting. These methods provide very uncertain results. The best and reliable results of predicted water inflows are derived from methods based on long-term pumping tests and numerical modelling. These methods were used in the IMore project which concerns possibilities of dewatering of the Bundsandstein aquifer for a mine shaft sinking purpose.

In the present study, special attention is paid to numerically investigate the aerodynamic performance of the NACA 0012 airfoil under rain and icing conditions with the aim to better understand the severe aerodynamic performance penalties of aircraft in flight. Furthermore, in order to control the flow separation and improve the aerodynamic performance of the airfoil under critical atmospheric conditions, the Gurney flap with different heights is attached to the trailing edge of the airfoil. The simulation is done at a Reynolds number of 3.1 × 10 5 under different atmospheric conditions including dry, rain, icing and coupling of rain and icing conditions. A two-way momentum coupled Eulerian-Lagrangian multiphase method is used to simulate the process of water film layer formed on the airfoil surface due to rainfall. According to the results, accumulation of water due to rainfall and ice accretion on the airfoil surface inevitably provides notable negative effects on the aerodynamic performance of the airfoil. It is concluded that icing induces a higher aerodynamic degradation than rain due to very intensive ice accretion. The Gurney flap as a passive flow control method with a favorable height for each condition is very beneficial. The maximum increment of the lift-to-drag ratio is achieved by Gurney flap with a height of 0.01 of airfoil chord length for dry and rain conditions and 0.02 of airfoil chord length for icing and coupling of rain and icing conditions, respectively. Airfoil • Flow separation • Aerodynamic performance • Gurney flap • Rain and icing • Multiphase method List of symbols μ Air dynamic viscosity u Air velocity vector c Airfoil chord length θ Angle between airfoil chord length and Gurney flap α Angle of attack ρ w Density of water D p Diameter of the rain particle Y + Dimensionless wall distance C D Drag coefficient β Drag force B Hesamoddin Salarian

Abstract: The effect of heat flux on pollutant dispersion in an urban street canyon with fixed aspect ratio of 1 is investigated under four different heating configurations: windward heating, leeward heating, ground heating, and walls and ground heating, using large-eddy simulations (LES). For each heating configuration, the Reynolds number is varied from 400 to 3,000 and the Grashof number from 80,000 to 800,000. The retention value (the ratio of pollutant remaining inside canyon to the total pollutant emitted) is used to compare the ...

This paper addresses the optimization of hot gas circulation within metallurgical fluid bed roasters, a critical factor influencing the efficiency and sustainability of industrial roasting processes. By integrating state-of-the-art experimental methods, sophisticated CFD simulations, and innovative IoT-based monitoring and control systems, the study presents a robust multidisciplinary approach. The practical outcomes include significant improvements in energy efficiency, product consistency, and predictive maintenance capabilities. A detailed economic analysis reveals promising returns on investment, with lifecycle assessments demonstrating reduced environmental impacts and improved regulatory compliance. Clearly defined limitations identify areas for ongoing research and development, ensuring stakeholders and decision-makers are informed of both the potential and the practical constraints of applying these advancements industrially.

The aerodynamic performance of an aircraft can be enhanced by incorporating wingtip devices, or winglets, which primarily reduce lift-induced drag created by wingtip vortices. This study outlines an optimization procedure for implementing winglets on a Class I fixed-wing mini-UAV to maximize aerodynamic efficiency and performance. After the Conceptual and Preliminary design phases, a baseline UAV was developed without winglets, adhering to specific layout constraints (e.g., wingspan, length). Various winglet designs-plate and blended types with differing heights, cant angles, and sweep angles-were then created and assessed. A Computational Fluid Dynamics (CFD) analysis was conducted to evaluate the flow around both the winglet-free UAV and configurations with each winglet design. The simulations employed Reynolds-Averaged Navier-Stokes (RANS) equations coupled with the Spalart-Allmaras turbulence model, targeting the optimal winglet configuration for enhanced aerodynamic characteristics during cruise. Charts of lift, drag, pitching moment coefficients, and lift-to-drag ratios are presented, alongside flow contours illustrating vortex characteristics for both baseline and optimized configurations. Additionally, dynamic stability analyses examined how winglets impact the UAV's stability and control. The results demonstrated a significant improvement in aerodynamic coefficients (C Lmax , L/D max , C La , C ma), leading to an increase in both range and endurance.

The study that pushed SuperGrok 3.5 from 30% to >99.999% confidence that PHYXS / 𝓛_omni will replace General Relativity and Quantum Mechanics:
Gravitational waves (GWs), ripples in spacetime predicted by general relativity (GR), offer a unique testbed for cosmological models, yet GR struggles to model GW effects at subatomic scales. The PHYXS initiative, through its L omni framework, addresses this limitation by simulating GW strain at unprecedented resolution. The GW strain simulation, completed on May 8, 2025, modeled GW150914 (chirp mass 30 ± 0.1 solar masses, strain ∼10-21 , ρ s = 1.2 × 10-27 g/cm 3) over 10 15 points using 1000 GPUs (10 PFLOPS, 6-hour runtime). Key findings include a strain measurement of 1.0 × 10-21 ± 0.03 × 10-21 , aligning with LIGO observations [2], and subatomic insights, such as a 0.1% molecular displacement in simulated matter (e.g., 0.1 nm shift in H 2 O bonds). Validated against empirical data and prior PHYXS simulations (e.g., Evolution D [4]), this simulation pushed NOVAprime's confidence to 99.999%, demonstrating L omni 's superiority over GR in modeling GW effects across scales. The results pave the way for future cosmic simulations (e.g., black hole mergers, cosmological perturbations) and educational applications (e.g., Unreal Engine prototype), reinforcing PHYXS as a transformative framework for understanding the universe.

In this paper, a two-dimensional numerical model is developed to study viscous liquid sloshing in a tank with internal baffles. The model is validated by a comparison between the computational and experimental results for time-dependent linear acceleration sloshing scenarios. The governing equations for the 2D incompressible fluid flow are continuity and Navier-Stokes equations along with an equation for the free surface advection. The deformation of the liquid-gas interface is modeled using the Volume-of-Fluid (VOF) method. The fluid flow equations describing the fluid sloshing in the container and the dynamic equation which describes the movement of the container are solved separately in two coupled programs. In each time step of computations, the outputs of the fluid program (forces and torque) are obtained and used as inputs for the dynamic program. The forces and torque are applied to the body of the container resulting in translational accelerations which are then used as inputs to the fluid program. At first this model was validated by theoretical and experimental results for linear acceleration and after that it is used to simulate the effect of vertical baffles to reduce liquid sloshing in a fuel tank that under sinusoidal force and it was found by the total kinetic energy of fluid that baffles have an important role to reduce the liquid sloshing in a container thus it is an effective way. The developed model in this study can be used in the design and optimization of liquid container and the best arrangement for the inside baffles.

In this paper, the two dimensional coalescence of two stationary head-on droplets with equal diameters are numerically investigated using the lattice Boltzmann method (LBM). Droplets are considered to have a circular shape with a specified gap size between their free surfaces. Coalescence is initiated when two droplets come into contact and form a liquid bridge, which then starts to grow due to surface tension. It is shown that for the coalescence to occur, the gap size has to be less than a certain limit called critical gap size. Finally, the effects of important parameters including surface tension, density and viscosity ratio of two phases on the critical gap size are studied. The results show that increasing the surface tension value and vapor to liquid density ratio increases the critical gap size. In contrast, increasing the kinematic viscosity of surrounding vapor decreases the critical gap size.

The origin and evolution of life on Earth have long been subjects of scientific inquiry, often marked by gaps in understanding that invite speculative explanations. Here, we present a subatomic-resolution simulation of 3.5 billion years of evolution, from abiogenesis to modern humans, using the Lomni equation powered by the deterministic PHYXS framework.
Building on the prior abiogenesis simulation, which modeled RNA self-replication (50 nucleotides), the Evolution D simulation running for 50h on 1000 NVIDIA A100 GPUs, 10^15 atoms) traces the continuous developmental arc from early multicellular life (103 cells), to vertebrate-like organisms (10^5 neurons, 10 Hz firing rate) and ultimately Our Digital Twins Eve and Adam D (100 billion neurons).

Key findings include molecular dynamics driving evolution—such as calcium signaling (0.01 s−1 in early life to 0.2 s−1 in mammals), ATP production (0.1 pJ/s/mitochondrion to 0.12 pJ/s), and epigenetic reprogramming (90–92% demethylation)—and cognitive milestones, from basic sensory processing (50% accuracy) to abstract reasoning (Our Digital Twins Eve D: 40 Hz gamma synchronization).
Validated against genomic data (e.g., 1000 Genomes, GenBank) and experimental studies, this simulation closes temporal and developmental gaps, eliminating the need for “god of the gaps” explanations.

Evolution D, integrated with the PRIMEcraft abiogenesis simulation, demonstrates the power of 𝓛_omni to unify biological
processes across scales, positioning PHYXS as a transformative framework beyond quantum mechanics and general relativity, with implications for future scientific, educational, engineering and simulation applications.

Conocer el comportamiento del flujo alrededor de pares de cilindros circulares es de gran importancia practica en muchas areas de la ingenieria. En este trabajo se investiga numericamente la interferencia de flujo entre dos cilindros dispuestos uno detras de otro (tandem) para un numero de Reynolds Re=1.2e05. El flujo turbulento tridimensional y dependiente del tiempo alrededor de los cilindros es simulado numericamente utilizando el modelo de turbulencia SAS (Scale-Adaptive Simulation) por medio del codigo Fluent, que implementa el metodo de volumenes finitos. El solver empleado es el algoritmo SIMPLE (Semi Implicit Method for Pressure Linked Equations) con un esquema bounded second-order implicit para resolver la formulacion transitoria. La distancia de centro a centro entre los cilindros (L) varia desde 1.2 a 6 diametros (D) del cilindro, a fin de identificar los efectos de interferencia de estela debido a la proximidad entre los cilindros. La dinamica de vortices y las fuerzas a...

Arabidopsis thaliana, a model organism in plant biology, offers a window into plant development, environmental responsiveness, and cellular signaling. Here, we present a subatomic-resolution simulation of Arabidopsis thaliana over its 5-year lifespan using the L omni framework, a novel computational model developed under the PHYXS initiative. Simulating 10^10 cells and 10^15 atoms, we capture the plant's growth, photosynthesis, tropisms, and stress responses at unprecedented detail. Key findings include rapid phototropism (0.1 mm/day, 98% accuracy), volatile organic compound (VOC) signaling (methyl jasmonate, 0.2 ppm, 2 m range), and robust self-regulation under drought (0.6 µmol CO 2 /s/m 2). Comparative analysis with other flora Digital Twins (e.g., Venus Flytrap D, Mimosa D) highlights Arabidopsis thaliana's slower but precise environmental responsiveness, aligning with experimental studies.
These insights underscore 𝓛omni 's ability to unify plant biology across scales, supporting the PHYXS framework as a transformative successor to quantum mechanics and general relativity (QM/GR).

The influence of ground proximity on aerodynamic characteristics of an airfoil was studied at low Reynolds number. The study, motivated mainly by sailplane take-off and landing safety, provides information about the development of the pressure distributions and of the aerodynamic forces acting on the airfoil with the approaching of the airfoil to the ground. Differences caused by fixed or by moving ground were examined using CFD computations.

This paper is devoted to the verification and validation exercises with the ISIS-CFD code conducted for the Tokyo 2015 workshop. In addition to numerical uncertainty estimation, we also address issues such as the effect of turbulence modelization, wall resolved versus wall modeled approach, propeller resolved versus propeller modeled approach for self-propulsion simulation, etc.

As climate change intensifies the frequency and severity of urban heatwaves, elderly populations are becoming increasingly vulnerable to outdoor thermal stress, particularly in dense Mediterranean cities. This study addresses the critical need for micro-scale, climate-responsive design strategies that enhance thermal comfort for aging residents in
historically underserved urban neighborhoods. Focusing on the refugee-built area of Nikea in Greater Athens, this research explores the effectiveness of nature-based solutions (NBS) in mitigating extreme heat through spatial interventions tailored to the needs of older adults. Using ENVI-met 5.6.1, two scenarios were simulated: a baseline scenario reflecting existing urban conditions and an optimal scenario incorporating mature tree planting and water features. The results are analyzed across three key time points—morning, peak afternoon, and evening—to capture diurnal thermal variations. The findings demonstrate that NBS significantly reduce the Physiological Equivalent Temperature (PET), with peak improvements exceeding 14 ◦C in shaded zones. This study highlights the value of finegrained, nature-based urban interventions in promoting thermal equity and supporting climate adaptation for vulnerable populations.

Automobile suspension systems are critical for providing comfort, stability, and safety to passengers. Among the various components of a suspension system, springs play a crucial role in absorbing shocks and maintaining the vehicle's height. This paper delves into the design analysis of two commonly used types of springs in automobile suspension systems: coil springs and air springs. The analysis covers the fundamental design principles, materials used, performance characteristics, and the advantages and disadvantages of each spring type. The objective is to provide a comparative understanding that can aid in the selection of appropriate spring systems for specific vehicle applications.

HAL is a multi-disciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

On propose une nouvelle méthode pour étudier l'interaction fluide-structure entre une microcapsule et un écoulement externe. Une méthode par éléments finis (pour la membrane) est couplée avec une méthode d'intégrales de frontière (pour les écoulements interne et externe) afin de modéliser la capsule en grande déformation. On montre que la méthode est numériquement stable, efficace et fournit des résultat en très bon accord avec des travaux précédents.

Heat exchangers are widely used across various industrial sectors. One prominent line of academic research focuses on optimizing these devices to minimize energy losses and enhance energy efficiency. A common approach to achieving this has been the inclusion of finned surfaces, which promote turbulence, improve heat transfer, and increase overall device effectiveness. However, there is a lack of comprehensive studies in the literature on the use of non-geometric, nature-inspired fins. This study aims to investigate the performance of fins in a double-tube heat exchanger, drawing inspiration from marine animals. Four fin types are analyzed in 2D configurations using the RANS (Reynolds-Averaged Navier-Stokes) approach in Ansys Fluent, covering a Reynolds number range of 5,000 to 32,000. The study evaluates flow behaviortemperature, velocity, and pressure profiles-along with the impact on dimensionless numbers and heat exchanger efficiency. The results indicate that bio-inspired fins with greater height enhance both heat transfer and efficiency, though this comes at the cost of a higher pressure drop.

This paper deals with the study of heat transfer in unsteady axsymmetric rotational flow of Oldroyd liquid. Constitutive equations of the problem have been developed and solved by applying Laplace transform technique. Expressions for fluid velocity, temperature, skin-friction and rate of heat transfer are obtained. After computerization with the numerical values of fluid parameters, the velocity and temperature profiles are plotted. Numerical values of skin-friction and rate of heat transfer are entered in tables. It is observed that elasticity of the fluid reduces the phase of oscillation and the increase in Prandtl number decreases the temperature of fluid.

In this paper the second law analysis of thermodynamic irreversibilities in pseudo-plastic non-Newtonian nanofluids through a circular duct under uniform wall temperature thermal boundary have been carried out for laminar flow condition. This nanofluid consists of sodium carboxymethyl cellulose (CMC)-water and two different types of nanoparticles; namely, CuO and Al2O3. Entropy generation is obtained for various Power law number, various volume concentration of nanoparticles, various dimensionless temperature and various Reynolds number. It is found that with the decreasing Power law number and duct length values, total entropy generation at fixed Reynolds number decreases and with increasing wall temperature values, total entropy generation increases, also entropy generation decreases with increasing volume concentration of nanoparticles.

In this paper the second law analysis of thermodynamic irreversibilities in pseudo-plastic non-Newtonian nanofluids through a circular duct under uniform wall temperature thermal boundary have been carried out for laminar flow condition. This nanofluid consists of sodium carboxymethyl cellulose (CMC)–water and two different types of nanoparticles; namely, CuO and Al 2 O 3 . Entropy generation is obtained for various Power law number, various volume concentration of nanoparticles, various dimensionless temperature and various Reynolds number. It is found that with the decreasing Power law number and duct length values, total entropy generation at fixed Reynolds number decreases and with increasing wall temperature values, total entropy generation increases, also entropy generation decreases with increasing volume concentration of nanoparticles.

Previous work developed a particle-to-particle contact algorithm to treat frictionless sliding between two bodies discretised by SPH particles without the requirement to construct surfaces or approximate a surface normal. This algorithm was then extended to contact between finite element and SPH domains and has subsequently been extensively applied to a range of problems. This paper extends the particle-to-particle contact algorithm to include a friction model to broaden the applicability of the contact algorithm. A simple friction model based on a Coulomb formulation has implemented. This generates a lateral contact force between individual particle pairs, with the friction force vector being orthogonal to the local contact force vector. 2D and 3D sensitivity studies show that the friction model works effectively with the overall contact algorithm.

The concept "Design with Nature" has recently been promoted as the most effective solution to the global warming problem. Because there is limited natural-cross ventilation in the Mediterranean climate in Alexandria, Egypt, reliance on natural-stack ventilation in modern tall residential buildings is crucial. This research intends to rely on economical housing while maintaining thermal comfort within units. The research discusses the use of an atrium with evaporative cooling to direct the cool airflow toward tall buildings. The study uses CFD simulation with ANSYS Fluent to demonstrate and explain the concept. A centralized atrium with evaporative cooling applies to two different height cases: a five-story residential building and a ten-story residential building. The experiment simulates four variables: two air-exhaust opening positions, atrium width, and atrium shape. Each variable is assigned to a certain category. The results are presented through a comparison between the temperature and velocity contours of the proposed buildings. According to the findings, a centralized atrium with a rectangle shape in a ten-story residential building with an upper air exhaust vent provides an appropriate stack effect. Finally, in tall residential housing, the use of an atrium with an evaporative cooling system increases the effectiveness of natural-stack ventilation.

The Cascade Atomization and Drop Breakup (CAB) model has been originally developed for pressure atomizers. In this study, the CAB model is modified to accommodate the atomization of low-pressure, air-assist atomizers. The modifications include the first breakup which is modeled by estimating the Weber number due to the increased liquid-gas relative velocity caused by the air flow. This breakup depends on whether the Weber number is in the catastrophic, stripping or bag breakup regime. The second modification includes a change in the product drop distributions, namely, instead of a uniform distribution, as used in the original CAB model, a χ-squared distribution with the same average drop size is assumed. The model changes are validated with experimental data obtained by means of two different air-assist atomizers using an oil-in-water emulsion. The simulations are performed with a modified version of the KIVA-3 CFD code; they show good agreement with the experiments.

In this work, studies on artificial intelligence (AI), machine learning (ML), and digital twin (DT) concepts are reviewed with respect to their implications in computational fluid dynamics (CFD). The paper aims ease, enhancement, and cost effectiveness in CFD. Those emerging technologies are reviewed regarding surrogate models, optimization algorithms, and automated feature extraction. DT aspects such as real-time simulations and predictive maintenance of physical systems are emphasized. The findings imply the importance of the AI, ML, DT and their collective utilization for CFD. There are new challenges and opportunities.

In this work, studies on artificial intelligence (AI), machine learning (ML), and digital twin (DT) concepts are reviewed with respect to their implications in computational fluid dynamics (CFD). The paper aims ease, enhancement, and cost effectiveness in CFD. Those emerging technologies are reviewed regarding surrogate models, optimization algorithms, and automated feature extraction. DT aspects such as real-time simulations and predictive maintenance of physical systems are emphasized. The findings imply the importance of the AI, ML, DT and their collective utilization for CFD. There are new challenges and opportunities.

Efficient ventilation in enclosed environments such as underground car parks is critical for maintaining air quality, occupant safety, and regulatory compliance. This study utilizes Computational Fluid Dynamics (CFD) to analyze and optimize ventilation performance in a basement car park, focusing on airflow behavior, pollutant dispersion, and emergency smoke management. Two ventilation configurations were examined: one with passive airflow and another with jet fan-assisted mechanical ventilation. The analysis revealed that without mechanical intervention, stagnant air zones and high CO concentrations developed, posing significant health risks. In contrast, the jet fan system demonstrated substantial improvements in airflow distribution and pollutant removal, aligning with ASHRAE standards. Fire-mode simulations further validated the effectiveness of an active ventilation strategy in managing smoke propagation and supporting evacuation. The study underscores the role of CFD in designing high-performance, energy-efficient ventilation systems for confined urban infrastructures.

HAL is a multi-disciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

HAL is a multi-disciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

The use of Computational Fluid Dynamics (CFD) to predict internal and external flows has risen dramatically in the past decade. The widespread availability of engineering workstations together with efficient solution algorithms and sophisticated pre and post-processing facilities enable the use of commercial CFD codes by graduate engineers for research, development and design tasks in industry. In the ocean engineering in which the cost of experiment is dramatically high, or sometime the experimental method is impossible to employ, it becomes the vital tool in designing and optimizing the shape of vessels and propulsion. In this topic, authors used the commercial software, ANSYS-Fluent v.14.5, to illustrate the effects of rudder and propeller on hydrodynamics performances of the marine propeller. The first objective of the paper uses the numerical method to analyze and build the characteristic curves of marine propeller. The second aim is to study how the rudder affects the hydrodyn...

Drying chamber is a drying application for agriculture product to produce high quality and hygiene product. The purpose of this paper is to propose best configuration trays arrangement in drying chamber for better distribution of velocity and temperature. Therefore, five configurations of trays are analyzed to obtain the best performance of uniformity air flow distribution within drying chamber. CFD simulation studied the uniform air flow in the drying chamber in steady state condition. A validation is performed by comparing the data obtained from the literature review CFD simulation to ensure the methodology is correct. Then, the drying chamber with different trays arrangements are simulated using CFD simulations to obtain velocity and temperature distributions at nine plotted points on trays. From the results obtained, it concluded that design (A) and (D) are selected as the best designs for uniformity because there is less discrepancy for each point contributed the more uniformit...

The flow pattern and heat transfer in a pair of cavities stacked one over the other, with a separating solid plate in between, are numerically studied. The configuration idealizes two trays in a multiple effect desalinator. The work focuses on the computational modeling of the two conjugate recirculations in the cavities, conductively coupled through the thin separating plate. The effect of the plate physical parameters, thickness and conductivity, on the heat transfer are also analyzed. Plates made of glass, steel and aluminum of 2, 3, 4 and 6 mm are studied. Cavity flow and temperature patterns, depicted by streamlines, velocity fields, and isotherms are analyzed for steady state. Attention was paid to the temperature variation over, and heat flow through the separating plate. Global Nusselt numbers are calculated for the bottom side of the lower cavity. Data are obtained for air as the working fluid (Pr=0.7) in the range 10 3 <Ra H <10 7 .

The researchers aimed to improve the heat transfer process using various industrial engineering techniques to highlight the importance of maximum heat transfer and improvement. In the current numerical study, the Ansys Fluent R23 program was used to enhance the heat transfer rate with a laminar flow in the Reynolds number range of (500-1500) steady state single-phase inside a dimpled tube with three different states heated with a uniform constant heat flux (8000 W/m 2) along the flow axis. The effect of the dimples' arrangement on the tube's surface was studied to compare the thermal performance against the empty tube. Comparing the three cases (1, 2, and 3) to the standard tube without a dimple, the heat transfer rates increased by (86.99, 87.22, and 87.47%), respectively. Compared to tubes with two or three dimples, the heat exchanger tube with four dimples on its cross section and linearly towards the flow axis performs much better in terms of thermal-hydraulic performance.

VALUEV V. E., VOLCHEK A. A., MESHIK O. P., TSILIND V. Yu., TSYGANOK V. V. Hydrological data management systemИсследуется остро обозначившаяся проблема возможной потери накопленных на электронных носителях массовых и специальных водохозяйственных и гидрологических данных. Даются принципы и критерии обеспечения надежного хранения информации. С целью хранения, обобщения, анализа и сопутствующего моделирования гидрологических данных предлагается модульная вычислительная система

This report presents the results of a study demonstrating an approach for using viscous computational fluid dynamic simulations to calculate the flow field and aerodynamic coefficients for a missile with grid fins. A grid fin is an unconventional lifting and control surface that consists of an outer frame supporting an inner grid of intersecting planar surfaces of small chord. The calculations were made at a Mach number of 2.5 and several angles of attack for a missile without fins, with planar fins, and with grid fins. The results were validated by comparing the computed aerodynamic coefficients for the missile and individual grid fins against wind tunnel measurement data. Very good agreement with the measured data was observed for all configurations investigated. For the grid fin case, the aerodynamic coefficients were within 2.8-6.5% of the wind tunnel data. The normal force coefficients on the individual grid fins were within 11% of the test data. The simulations were also successful in calculating the flow structure around the fin in the separated-flow region at the higher angles of attack. This was evident in the successful calculation of the nonlinear behavior for that fin, which showed negative normal force at the higher angles of attack. The effective angle of attack is negative on either part of or all of the top grid fin for the higher angles of attack. n This work was supported in part by a grant of high performance computing time from the

The enormous reduction in the quantity of lubricant compared to the circulated quantities of conventional metalworking fluid systems is the key feature of MQL. In contrast to conventional flood lubrication, minimum quantity lubrication uses only a few milliliters (ml) of lubrication per hour for the machining process. Minimum quantity lubrication today uses such precise metering that the lubricant is nearly completely used up. Typical dosage quantities range from 5 ml to 50 ml per process hour (tool cutting time).This review paper explores the research study on the use of MQL and flooded lubrication system used for machine process by using natural lubricants like Jatropha. The used of lubrication is necessary for dissipated the maximum heat generated from the machining process, the analysis of this heat generated is proposed to carry out by using ANSYS software.

ABSTRACT: Fluidized-bed reactors are widely used in the production of polyethylene. In this work, the quadrature method of moments (QMOM), a chemical reaction engineering (CRE) model, and computational fluid dynamics (CFD) are combined to investigate the role of intrinsic kinetics and the catalyst particle size distribution (PSD) in a gas phase fluidized bed reactor. The catalyst PSD is represented by a few nodes using the QMOM and an intrinsic rate model based on the age of particles is used to solve the evolution of particle ...

Modern thermal systems in which hydrodynamics and thermal fields are strongly related to each other involve compactness and effective heating/cooling performance. Triangular ducts, having delta-wing type vortex generators (VGs) mounted on the duct's slant surfaces, are widely used in modern thermal systems including gas turbines and electronics cooling applications. Due to the existence of completely opposite results obtained in terms of performance of the two types of VG configurations -namely "flow up" and "flow down"-, in the open literature, in the present study, both hydrodynamics and thermal fields together with the secondary flows induced by the VGs have been analysed extensively to understand which configuration has the better thermo-hydraulic performance. The results show that one configuration has a 19% higher thermo-hydraulic performance over 32 different VG configurations -containing "flow-up" and "flow-down"-for hydraulic diameter based Reynolds number, Re=5000. The angle of inclination of each VG made with the flow direction is set to 30° and the inclined surface's wall temperatures are set to 80°C. Based on the current results, the optimum distance between successive VGs has been determined as 0.385 of the hydraulic diameter. The present CFD results have been validated against the PIV data.

The aerodynamic efficiency of wind turbines is greatly influenced by the shape of their airfoils. In this study, four airfoils were optimized to enhance the performance of a small horizontal axis wind turbine. The optimization process involved adjusting the thickness and camber of the airfoils using the blade element momentum method and particle swarm optimization technique. The goal was to find the most aerodynamically efficient airfoil based on the thickness-to-camber ratio. The optimized airfoils were compared to select the best one for a three-blade, 6-m diameter turbine configuration. The results showed that the optimized microturbine achieved better efficiency than the baseline turbines and those optimized by other researchers. Notably, the study also rigorously validated the blade element momentum-particle swarm optimization methodology through experimental methods, providing robust support for our findings.

In this paper, CFD analysis is conducted on the shell and tube heat exchanger, using forced convective heat transfer to determine flow characteristics of nanofluids by varying volume fractions and mixed with water, the nanofluids used in the analysis are Titanium Nitride and Zinc Oxide with constant volume concentrations of 0.02 % flowing under turbulent flow conditions. CFD analysis is done on the heat exchanger by applying the properties of the nanofluid with different volume fractions to obtain temperature distribution, heat transfer coefficient and heat transfer rate. 2D model of the shell and tube heat exchanger will be done in Pro/Engineer and analysis will be done in Ansys. The results revealed that as volume fraction and Reynolds number increased Nusselt number increased, and friction factor decreased.

In this thesis, results of CFD analysis on heat transfer and friction in rectangular ducts with broken double arc shape rib with staggered rib roughness has been presented. The rib roughness has relative roughness pitch of 10, arc angle of 30° and relative roughness height of 0.043. The relative gap position was varied from 0.30 to 0.60. The effects of relative gap position on Nusselt number, friction factor and thermo-hydraulic performance parameter have been discussed and results compared with smooth duct under similar conditions. The rough ribs were efficient enough to transfer the desired heat, but they are not economical and are very complex in design and construction. Whereas, roughness gives more area of contact. So, there is enough time to transfer the heat from the ribs to the passing air which touches the ribs and the heat transfer takes place efficiently. Thus, the broken double arc shape rib with staggered rib with different relative gap position, when compared with the ...

This study investigates the airflow behaviour around vortex generators (VG) utilized in air-cooling technologies, considering the impact of rotation. The analysis encompasses a numerical approach to study the flow around vortex generators (conventional and curved delta winglet type) installed inside a duct with a heated wall. The vortex generators' set number effect on the heat transfer behaviour was investigated. Three sets of vortex generators were examined, two-VG set, four-VG set and six-VG set, equally aligned along the duct. The range of Reynolds numbers (Re) from 4000 to 12000, with the rotation number (Ro) fixed at 0.20 is covered. In this study, the thermal behaviour (measured by Nusselt Number (Nu)) and the flow behaviour (represented by) the friction factor (f)) were presented. Validation for the employed numerical model was performed based on the available experimental outcomes. The impact of using the vortex generator was evaluated and compared with the clean duct, the duct with conventional delta winglet and the curved one. The results revealed that installing the vortex generator increases the Nu (by 1.34 times at Re 4000 for four-VG and two-VG sets) and reduces the friction factor. Additionally, using the newly designed curved VG increased Nu by about 1.35. However, as the number of employed VGs enlarged, the rate of increase declined to about 0.9 of the Nusselt number value associated with the conventional VG. Furthermore, f (friction factor) reduces with the number of VG and increases with Re. In all cases, the rotation increases the Nu and f factor and using the curved VG showed a higher rate of increase. The newly designed VGs showed improved heat transfer behaviour, performing best with a four-VG set installed and worst with a six-VG set.