Progress in Computational Fluid Dynamics, An International Journal (11 papers in press)

Regular Issues

• 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
   
  
• Optimisation of Drag reduction for Passive flow Control based on a Notchback MIRA model  
  by Xingren Zheng, Lingxi Deng, Zihou Yuan, Yanming Du, Hongwei Zhang 
  Abstract: This paper investigates the application of passive flow control for optimising automotive aerodynamic drag reduction, based on a notchback MIRA model. The study uses a computational fluid dynamics (CFD) simulation, a neural network prediction model and a genetic algorithm to optimise and combine the body geometry features and duckwing add-ons in a step-by-step manner. The results show that optimising the body independently reduces the drag coefficient (CD) by 12.4%, while optimising the duckwing independently reduces it by 21.109%. Combining the optimal parameters of the body and the duckwing in a composite optimisation scheme reduces the drag coefficient of the whole vehicle to 0.24509 up to 24.09% less than the original model. Flow field analysis shows that composite optimisation significantly improves rear flow field structure, effectively compresses the low-speed region and significantly reduces turbulence intensity while enhancing tail pressure recovery. This study provides an efficient optimisation strategy for the design of automotive aerodynamic drag reduction, which is important for improving vehicle energy efficiency and reducing emissions.
  Keywords: computational fluid dynamics; CFD; artificial neural network; ANN; genetic algorithm; GA; automotive aerodynamics; passive flow control; parameter optimisation.
  DOI: 10.1504/PCFD.2025.10074740
   
  
• Optimal Impeller Design for an Intravascular Ventricular Assist Pump: A CFD-based study  
  by Amir Alaei-Baher, Hanieh Niroomand-oscuii, Reza Sahebi-Kuzeh Kanan, Erfan Namaki 
  Abstract: Today, new ventricular assist devices are catheter-inserted as a temporary solution for acute heart failure patients awaiting a heart transplant. This study designed a novel intravascular left ventricular assist pump inserted via a catheter, emphasising its compact design. The primary design challenge was selecting the optimal impeller. Using numerical simulation based on the Archimedean screw theory, eight impeller models, varying in pitch length and blade rotations, were examined for the axial flow pump. Performance was assessed across rotational speeds (13,260 to 19,260 rpm). The optimal impeller, selected based on the operating point (5 l/min and 80 mmHg at 16, 260 rpm) and the hemolysis index, featured a pitch length of 9.2. Results confirm the pumps potential for clinical use, offering high efficiency and low risk of blood damage. The novelty is the impeller design using the Archimedean screw concept and the methodology for determining the pitch steps.
  Keywords: Intravascular ventricular assist device Axial flow pump Acute heart failure Archimedean screw Hemolysis.
  DOI: 10.1504/PCFD.2025.10075159
   
  
• Numerical Investigation on Head-On Droplet Collisions based on Modified Coupled Level Set-VOF  
  by Xiaohang Qu, Qianjian Guo, Xiaoni Qi 
  Abstract: Seawater droplet collision phenomenon exists widely in marine environments. A model is developed for the collision process of seawater droplets composed of various salts. The head-on collision of binary equal-sized seawater droplets has been investigated based on the phase interface tracing method of coupled level set-VOF with the adaptive mesh refinement. The initialisation method of phase function, the solution method of convection transport equation of the phase function, the construction and realisation method of phase interface and the method of function re-initialisation are developed. The tetradecane droplet collisions are numerically studied to validate the numerical method. The results show good agreement with experimental data from the literature. The head-on collisions of seawater droplet are first numerically investigated at various Weber numbers (from 0.5 to 200). Different collision outcomes have been observed for various parameters, such as coalescence and reflection separation. The critical Weber number of separation is obtained. The evolution of the droplets kinetic energy, the surface energy and the dissipation energy as well as the maximum deformation for seawater droplets is also evaluated. This work contributes to a fundamental understanding of the mechanism of seawater droplet collision and the application of droplet collision models to related processes.
  Keywords: Droplets collision; Seawater; Numerical investigation; Modified Coupled Level Set-VOF (M-CLSVOF).
  DOI: 10.1504/PCFD.2025.10075233
   
  
• Numerical investigation for the flow past a single, and in-line stick-slip cylinder in a planar flow  
  by Manish Dhiman  
  Abstract: Flow past bluff bodies is a fundamental problem in fluid mechanics. Recently, the influence of confinement on such flows has gained significant attention, as nearby no-slip walls can markedly alter phenomena like flow separation and stagnation points. Concurrently, the development of Janus cylinders materials with distinct surface properties have shown considerable promise in various applications. In this study, flow structures and hydrodynamic forces on a circular stick-slip (Janus) cylinder, centrally placed within a confined channel, are investigated at low cylinder Reynolds numbers (Rep = 1100) for different channel-to-cylinder diameter ratios (H/D). Comparisons are made with conventional uniform-surface (stick) cylinders. Results show that the recirculation zone enlarges with increasing H/D, and shear stress distributions indicate that separation points shift further downstream. Empirical correlations for drag, lift, and moment coefficients are proposed. Additionally, the flow over two in-line stick-slip cylinders is analysed, revealing significant alterations in streamline patterns and hydrodynamic forces.
  Keywords: Stick-slip cylinders; confinement; in-line array.
  DOI: 10.1504/PCFD.2025.10075737