Progress in Computational Fluid Dynamics, An International Journal (15 papers in press)

Regular Issues

• Hydrodynamic Effects of Strut on 3D Hydrofoils Near Free Surface in Cavitating and Non-Cavitating Conditions at Various Velocities and Angles of Attack  
  by Aliakbar Ghadimi, Hassan Ghassemi, Parviz Ghadimi, Alireza Pourmansour 
  Abstract: Hydrofoils are connected to vessels through geometrically complex struts to reduce resistance while maintaining vessel performance. This study explores the effects of various factors, including the presence of struts, on the hydrodynamic behavior of hydrofoils near free surface under both cavitating and non-cavitating conditions. Using the RANS solver and VOF model in StarCCM+ software with the Saur model for cavitation, the performance of two 3D hydrofoil cross-sections, NACA0012 (symmetric) and NACA6612 (asymmetric), was analyzed. Simulations indicate that the lift-to-drag ratio decreases with increasing angles of attack and immersion ratios for both hydrofoil types, though asymmetric hydrofoils consistently achieve higher lift-to-drag ratios than symmetric ones. Additionally, the inclusion of a strut significantly enhances the lift-to-drag ratio in both cavitating and non-cavitating conditions, with the asymmetric NACA6612 showing superior performance compared to the symmetric NACA0012.
  Keywords: Hydrodynamic performance; Hydrofoils; Strut; NACA6612; NACA0012; Cavitation; Numerical simulation.
  DOI: 10.1504/PCFD.2025.10069237
   
  
• Computational Fluid Dynamics-Based Analysis of Seepage Flow Through Concrete Dam  
  by Biri Singh, Anubhav Rawat 
  Abstract: Seepage is an essential aspect of dam structural study. Finite element method (FEM) based models have so far been used to predict seepage behaviour under dams. In the current work, Finite Volume method (FVM) based computational fluid dynamic (CFD) is employed in a novel way because FVM is frequently more computationally efficient for solving the flow problems. The CFD model used in the current work could accurately capture the physics of seepage under concrete dams. A detailed parametric investigation is carried out to establish seepage flow analysis through the dam. The dam's depth and width are inversely proportional to the seepage rate, and seepage velocity varies linearly with the water level head. Further, sand layer arrangements of different porosities are made in the dam at various locations to judge the effect of porosity arrangement on seepage. Analysis of grout curtain width is also done at different positions and angles in the dam. It is found that the upstream side location of the dam is best suited for grout curtains for minimum seepage.
  Keywords: Seepage flow; CFD; Concrete dam; Sand porosity; Grout curtain.
  DOI: 10.1504/PCFD.2025.10069857
   
  
• Effects of Trailing Edge Design on Flow around a Two-Element Airfoil Placed near a Wall  
  by Dilip Lalchand Parmar, Deepak Kumar Singh, Arjun Sharma 
  Abstract: Effects of presence of a wall on aerodynamics of two-element airfoils are studied at Reynolds number of 50000, angle of attack of 5 degrees and varying flap overlap. The primary geometry of airfoil has NACA0012 section as the main element along with a slotted flap. A second geometry for the main element is obtained by local modifications, in the form of downward tilt at the trailing edge and shaping of overlap region. Lift coefficients increase significantly with reduction in wall-distance for both geometries. Geometric modifications at the trailing edge of main element cause higher pressure due to flow blocking on the lower side as well as higher exit speed with flow alignment along the flap surface on the upper side. Improvements in lift coefficients due to geometric changes vary from 7% to 11% when the wall-distance decreases from 1 to 0.15 times the chord length of main element.
  Keywords: High-lift system; two-element airfoil; ground effects; shape modifications; adjoint-based gradient.
  DOI: 10.1504/PCFD.2025.10070014
   
  
• Computational Investigation of Low-Reynolds-Number Unsteady Flows Past NACA0012  
  by Mertcan Güney, Berkan Anilir, Kurtulus Dilek Funda 
  Abstract: The aerodynamic characteristics of airfoils are significantly governed by the Reynolds number, particularly in the low Reynolds number regime (Re < 1
  Keywords: NACA 0012; unsteady aerodynamics; low Reynolds number; computational fluid dynamics.
  DOI: 10.1504/PCFD.2025.10071614
   
  
• Numerical Investigation of an Airfoil using Leading Edge Rotating Cylinder  
  by Dheeraj Minglani, Vandana Saxena, Ritu Dahiya, A. Anu Kuttan, Laviza Aqeel, Yash Mahore 
  Abstract: This study presents a detailed numerical investigation of the aerodynamic performance of a NACA 0015 airfoil enhanced with a leading-edge rotating cylinder. A parametric analysis was conducted to evaluate the effects of rotational speed (10, 50, 100, 150 and 200 rad/s), cylinder diameter (13, 14 and 15 mm), angle of attack (5, 10, 15, 20, 25 and 30), and the Reynolds number varies with free-stream velocities of 15, 30, 50, and 100 m/s, with corresponding values of 152,279, 304,558, 507,597, and 1,015,193, respectively on the lift coefficient. A non-dimensional parameter, the cylinder surface velocity to free-stream velocity ratio was introduced to assess its influence on flow characteristics and lift enhancement. Results reveal that higher rotational speeds and larger cylinder diameters significantly increase lift coefficient, particularly at elevated angles of attack, with peak lift occurring between 15 and 20. Higher Reynolds numbers further amplify aerodynamic efficiency by delaying flow separation. These findings, supported by validated computational simulations and a predictive polynomial model, highlight the leading-edge rotating cylinder potential as an effective active flow control mechanism. This research provides novel insights into optimising airfoil performance for applications in aerospace, unmanned aerial vehicles, and renewable energy systems.
  Keywords: Airfoil; NACA 0015; Leading Edge Rotating Cylinder; lift coefficient; angle of attack; rotational speed.
  DOI: 10.1504/PCFD.2025.10071760
   
  
• Impact of a Four-Hydrofoil Configuration on Trimaran Resistance: Two Angled Bow Foils on Longer Struts and Two Stern Foils on Shorter Struts  
  by Aliakbar Ghadimi, Hassan Ghassemi, Parviz Ghadimi 
  Abstract: This study investigates how installing four NACA0015 hydrofoils to a trimaran hull affects performance, aiming to reduce fuel consumption by minimizing resistance. Using Star-CCM+ and URANS equations, the research analyzed the impact of two angled hydrofoils at the bow and two angled at the stern on a trimaran's performance. The methodology involved modeling the trimaran, hydrofoils, and struts, creating a computational domain with appropriate boundary conditions, and performing mesh independence testing. Validation was achieved through a catamaran simulation. Results at Froude numbers ranging from 0.8 to 1.5 showed improved CL/CD ratios with hydrofoils. Meanwhile, trim improved at lower speeds but decreased at higher speeds. Pressure resistance increased, while frictional drag was significantly reduced at high speeds. Overall, total resistance increased at lower speeds but decreased at higher speeds, notably a 44.8% reduction at Froude number 1.5, demonstrating the potential of these hydrofoil configurations for improved high-speed efficiency.
  Keywords: Trimaran; hydrofoil; resistance reduction; CFD; High-speed planing hull; numerical analysis; Star-CCM+.
  DOI: 10.1504/PCFD.2025.10072680
   
  
• Thermosolutal Mixed Convection Flow in a Vertical Pipe with Heat Generation/Absorption and Hydromagnetic Effects  
  by Saurabh Kapoor, Durgaprasad Nayak 
  Abstract: This manuscript investigates the thermosolutal mixed convective flow in a vertical pipe within a porous medium, together with a transverse magnetic field. The fluid is assumed to be fully developed, electrically conducting, and heat-generating/absorbing. The non-Darcy Brinkman- Forchheimer-extended model is used to understand the flow in the porous medium. Numerical solutions for the coupled differential equations have been obtained using the Chebyshev spectral-collocation approach. It is observed that, under limiting conditions, our numerical results are in good agreement with the available existing numerical data. An unnatural deviation is observed in both the velocity and temperature profiles beyond a certain value of the heat generation parameter. Initially, increasing the magnetic field strength reduces the fluid velocity. However, beyond a threshold, the velocity profile flattens across the domain, while the temperature profile increases and the concentration profile decreases. Elevated drag forces within the medium result in smoother and flatter velocity profiles. An increase in the heat absorption parameter leads to higher peak temperatures and concentrations.
  Keywords: Porous medium; Heat generation/absorption parameter; Hartmann number; Spectral collocation method.
  DOI: 10.1504/PCFD.2025.10073090
   
  
• A Systematic Review on Aerodynamics and Aero-Acoustics of Supersonic Jets  
  by Amiruzzahan Mondal, Shashi Kant Verma, Saif Akram 
  Abstract: This study presents a comprehensive review of the aerodynamics and aero-acoustics of supersonic jets, with an emphasis on active and passive flow controls that improve mixing effectiveness and noise reduction. The study explores the impact of various control techniques, such as tabs, grooves, and fluid injectors, on noise reduction, shock structures, and jet core dynamics. The impact of Mach numbers, Strouhal numbers, NPRs, overexpanded and under-expanded conditions on jet flow properties is assessed using both experimental and numerical data. The research attempts to provide a coherent knowledge of jet behaviour and its underlying mechanisms by combining data from multiple investigations. By comparing the results of different active and passive flow control techniques, ventilated and delta tabs are found to be the best methods for attaining exceptional performance. The best control technique, which enhances the jet mixing and noise reduction, is identified, and the schematic of the proposed tab is presented.
  Keywords: Supersonic Jet; Aero-Acoustics; Flow Control; Nozzle pressure ratio; Mach number.
  DOI: 10.1504/PCFD.2025.10073607
   
  
• Machine Learning and Deep Learning Techniques for Enhancing Computational Fluid Dynamics: a Comprehensive Review  
  by Alireza Omrani, Arman Shateri, Arash Goligerdian, Hamid Majidi, Seyed Behzad Hosseini, Saman Aminian, Mohammad Hafezi 
  Abstract: Over the years, computational fluid dynamics (CFD) has undergone significant evolution, establishing it as an essential tool for simulating complex fluid flow phenomena. The integration of deep learning (DL) and machine learning (ML) methodologies with CFD has recently emerged as a promising approach to enhance the accuracy, efficiency, and automation of simulations. This comprehensive review article explores the potential of ML and DL in advancing CFD, providing valuable insights into their transformative impact on the field. In this study, the large eddy simulation (LES), reduced-order models (ROMs), Reynolds-averaged Navier-Stokes (RANS), and direct numerical simulation (DNS) techniques, along with the role of ML in improving these models within CFD, are thoroughly discussed. It was demonstrated that ML and DL techniques can accelerate high-fidelity simulations, provide turbulence models with varying levels of precision, and generate ROMs that surpass the accuracy achieved through conventional methods. Additionally, this paper presents a broad perspective, highlighting recent advancements, opportunities, and unresolved challenges in the field.
  Keywords: Machine learning; Computational fluid dynamics; Reduced-order models; Deep learning; Artificial neural network.
  DOI: 10.1504/PCFD.2025.10073770
   
  
• Investigation using a One-Way Coupled FE-Structural and FV-Hemodynamic Simulation for Identifying the Factors causing the Progression of a Saccular Aneurysm Model  
  by Suraj Raj, ANIL L.A.L. S, Anjan R. Nair 
  Abstract: Rupture risk assessment of cerebral aneurysms through computational modelling has gained importance due to the absence of objective clinical methods and challenges in experimental approaches. This study uses a one-way FSI approach with a non-Newtonian Carreau viscosity model on an idealized 3D saccular aneurysm in a curved artery to analyse key hemodynamic and structural parameters. Velocity magnitude, time-averaged wall shear stress (TAWSS), oscillatory shear index (OSI), vorticity magnitude, von-Mises stress, and total displacement were evaluated across the cardiac cycle. A low-velocity stagnation zone was observed within the aneurysm sac. TAWSS was lower inside the sac but peaked near the distal end, where OSI values exceeded 0.2, reaching up to 0.45, indicating vulnerable regions. Vorticity and q-criterion analyses highlighted disturbed, vorticity-dominated flow regions. Maximum von Mises stress and displacement were observed near the distal regions, suggesting that shape distortions contribute significantly to aneurysm progression and rupture risk.
  Keywords: Cerebral aneurysm; rupture risk assessment; computational modelling; fluid-structure interaction (FSI); non-Newtonian; Carreau model;wall shear stress (WSS); oscillatory shear index (OSI); vorticity.
  DOI: 10.1504/PCFD.2025.10073915
   
  
• The Paradigm Shift of Convective Instability in Pipe Flow: a Comprehensive Review  
  by Saurabh Kapoor, Durgaprasad Nayak 
  Abstract: This article provides a comprehensive overview of various methods used to enhance the thermal performance of heat exchangers, along with the stability mechanisms of convective flows. Heat transfer occurs through three primary modes: radiation, conduction and convection. Among these, convection is one of the most significant and can be categorised as free, forced, granular, gravitational or thermomagnetic. Over the past few decades, numerous studies have investigated convective heat transfer in pipes. This paper presents a detailed review of fluid flow in pipes, aiming not only to evaluate previous research comprehensively but also to provide readers with valuable existing knowledge that may facilitate future studies. The effects of key dimensionless parameters such as the Rayleigh, Reynolds, Prandtl, Grashof, Nusselt and Darcy numbers, as well as pipe length, on heat transfer are also discussed. Additionally, the paper includes a brief discussion on the instability mechanisms of mean flow in pipes based on recent stability analyses.
  Keywords: Porous Medium; Poiseuille Flow; Convection; Heat Transfer; Double Diffusion; Stability Analysis.
  DOI: 10.1504/PCFD.2025.10074278
   
  
• A study of simultaneous pitching and plunging motions of an airfoil using the spectral element method  
  by Jose Gilberto Montiel-Galindo, Ruben Avila, Syed Shoaib Raza 
  Abstract: In this study, the thermal convection of the laminar flow over a symmetric NACA 0012 airfoil with simultaneous pitching and plunging motions is presented. The non-steady, two dimensional, Navier-Stokes equations coupled with the energy equation, considering the Boussinesq approximation, are numerically solved by using the spectral element method. The influence of the Rayleigh number (the magnitude of the buoyancy force) on the aerodynamic coefficients and the Nusselt number (the heat transfer rate), is analysed. It is found, for a given value of the Reynolds number (Re = 1,000), that an increase of the buoyancy force leads to a decrease of the performance, although increasing the mean geometric angle of attack α_m reduces this effect. Moreover, we note that if α_m = 0°, the heat transfer is reduced as the buoyancy force increases; however, if α_m ≥ 10°, as the buoyancy force gets higher values, the heat transfer also increases.
  Keywords: low Reynolds numbers; Rayleigh number; Nusselt number; pitching motion; plunging motion; heat transfer; buoyancy force; aerodynamic performance; SEM; spectral element method.
  DOI: 10.1504/PCFD.2025.10071544
   
  
• Non-dimensional parametric optimisation of hydraulic performance of centrifugal pump using response surface analysis  
  by Durvesh Yadav, Rajkumar Singh, K. Manjunath 
  Abstract: In this study, the hydraulic performance of a single-stage centrifugal pump at the rated point was enhanced using the response surface methodology (RSM). By establishing an approximate relationship between the design head coefficient and flow coefficient, key geometric variables such as the number of blades, flow rate, and rotation were selected as decision variables. The head and flow coefficients were considered as responses. Utilising a central composite design (CCD) and computational fluid dynamics (CFD) in Design-Expert software, optimised impeller designs were evaluated. Experimental validation through 20 tests showed an average error of 6.21% for head, 5.77% for efficiency, and 7.13% for output power. The optimised pump model, featuring 7 blades, operating at 1,900 rpm, and delivering 450 m
  Keywords: optimisation technique; response surface methodology; RSM; computational fluid dynamics; CFD; number of impeller blades; rotation; single-stage centrifugal pump.
  DOI: 10.1504/PCFD.2025.10070078
   
  
• Prediction of pressure gradient in gas liquid flow based on meta-learning methods  
  by Zhenzhen Dong, Zhanrong Yang, Weirong Li, Xiaowei Zhang, Wei Guo, Tong Hou, Guoqing Dong 
  Abstract: Gas liquid flow models in wellbores are crucial across various stages of the petroleum industry. Accurate pressure drop prediction in these flows is vital for optimal production schedules. Traditional models face challenges such as uncertain prediction boundaries and complex parameter computations, lacking universal applicability. Leveraging advances in machine learning, this paper introduces a predictive model for pressure gradients in gas liquid flow. Utilising 862 samples from experimental literature, the data were preprocessed, cleaned, and split into training and validation sets. Employing R2 and RMSE as evaluation metrics, the optimal model was identified using meta-learning, combining decision tree, random forest, K-nearest neighbours, XGBoost and LightGBM as base models, with XGBoost as the meta-model. The model achieved an R2 of 0.9826 and RMSE of 2.8200, highlighting key factors influencing gas liquid flow and emphasising the model's accuracy and significance.
  Keywords: pressure gradient; gas liquid flow; machine learning; meta-learning.
  DOI: 10.1504/PCFD.2025.10071218
   
  
• Comparing single vs. two-phase models for Al₂O₃-H₂O nanofluid in minichannels  
  by Abdelkder Mahammedi, Driss Meddah Medjahed, Abderrahmane Amari 
  Abstract: CFD predictions of a steady laminar forced convective heat transfer of a nanofluid AL₂O₃-water mixture in a horizontal 2D minichannel were studied numerically. The governing equations for the classical Newtonian nanofluid and the approach founded on the two-phase models had been numerically solved using Fluent CFD software. The impacts of the Nusselt number, volume concentration, coefficient of heat transfer, wall temperature, pressure drop, and hydrodynamic flow were studied via single-phase fluid and two-phase (Eulerian, mixture) models. A numerical process comparison with available numerical and experimental data was done to ensure the validity and reliability of the models, where a satisfactory agreement was found. Heat transfer efficiency raises as the nanoparticle volume concentration and Reynolds number rise, and the results of two-phase modelling demonstrate a larger enhancement of heat transfer compared to those from a single-phase model.
  Keywords: CFD predictions; nanofluid; two-phase model; laminar forced convection; heat transfer; Nusselt number; Fluent; pressure drop.
  DOI: 10.1504/PCFD.2025.10069525