This study explores the magnetohydrodynamic (MHD) pulsatile flow of Jeffrey liquid layers separated by a micropolar liquid layer, confined between two permeable beds. The flow domain is divided into three distinct regions: Regions A and C, which contain Jeffrey fluid, and Region B, which contains a micropolar fluid. The liquid-permeable bed interfaces are governed by the Beavers-Joseph slip boundary condition. The governing equations are solved numerically using the NDSolve function in Mathematica. The effects of various physical parameters on velocity profiles, mass flux, and microrotation velocity are illustrated graphically. Additionally, stress distributions are analyzed and presented in tabular form. The results reveal that the applied magnetic field has a pronounced influence on the flow characteristics compared to the purely hydrodynamic case. Our analysis indicates that the stress distribution at the permeable boundaries increases with Reynolds number, slip coefficient, porosity, and Jeffrey fluid parameters. Furthermore, mass flux is found to increase with the Reynolds number, Jeffrey parameter, and micropolar material parameter, while it decreases with an increase in the Hartmann number. A comparative analysis of our results with other researchers shows good agreement.
This study examines the influence of Propeller Boss Cap Fins (PBCFs) on the hydrodynamic performance of B-series propellers by introducing variations in installation angles. While PBCFs are widely recognized for their potential to reduce rotational losses and enhance propulsion efficiency, the specific impact of installation angle variation-particularly in the context of electric-powered vessels- has remained underexplored. To address this gap, the present work focuses on the aerodynamic optimization of PBCFs, varying the installation angle between-5 degrees and 5 degrees, using a NACA4412 airfoil profile within a Computational Fluid Dynamics (CFD) framework. The analysis is conducted using the Reynolds-Averaged Navier-Stokes (RANS) approach with a Grid Independence Test (GIT) performed to ensure numerical accuracy. Validation of the simulation results against available experimental data confirms the reliability of the model. The configuration featuring a 2 degrees PBCF installation angle demonstrates the most favorable performance, yielding an increase in the thrust coefficient (KT) from 0.3719 to 0.3797 and an improvement in open water efficiency (eta) by 4.3% relative to the baseline CFD model. Additionally, a maximum efficiency enhancement of 24% is observed when compared to experimental data at an advance coefficient of J = 0.415. The validation results exhibit a maximum deviation of 9.934% at lower rotational speeds, which is within an acceptable range for engineering applications, particularly given the challenges of modeling complex flow phenomena at low Reynolds numbers. The principal contribution of this study lies in its systematic evaluation of PBCF installation angle as a design variable-an area that has received limited attention in existing literature. The findings demonstrate that even minor angular modifications can significantly influence propeller performance. More broadly, this research contributes to the advancement of energy-efficient marine propulsion technologies by offering a validated, CFD-based design methodology. The implications are particularly relevant for the development of sustainable propulsion systems in electric and low-emission vessels, supporting broader efforts to reduce fuel consumption and minimize environmental impact in maritime operations.
Accurate numerical simulation of flow over bodies, when there is an angle of attack, is challenging even when the body is slender and axisymmetric. Two methods are widely used in such simulations, but no study clearly compares the accuracies and the advantages and disadvantages of the methods. In the body rotation method (BRM), the flow is along the axis of the domain, and the body is rotated such that the angle between the main axis of the body and the flow direction is the angle of attack. In the flow rotation method (FRM), the axis of the body is along the axis of the domain, and the direction of the flow is changedto simulate the angle of attack. In the present study, both methods are usedat a Reynolds number of 12 x 10(6). The Computational Fluid Dynamics (CFD) package is used to simulate flow over an axisymmetric three-dimensional (3D) bare hull submarine model, and the angle of attack is varied from 0 degrees to 18 degrees. In both BRM and FRM approaches, steady Reynolds Average Navier Stokes (RANS) equations are solved using the k - omega Shear Stress Transport (SST) turbulence model, with non-dimensional wall adjacent cell thickness (Y-omega(+)) kept below1. The same domain and mesh commands are used in both methods. The hydrodynamic forces, moments, coefficients of wall shear stress, and pressure computed using the two methods differ by less than two percent. The distribution of the sizes of cells and the number of cells of various shapes are also presented. When meshed with cells in the wall-adjacent region having the same size, the number of cells and computation time are much less in the body rotation method, and it is therefore preferred.
In the present study, a comprehensive experimental and numerical investigation has conducted to simulate and predict the thermal profile in weld joints of modified 9Cr-1Mo (P91) steel plates, with a particular focus on the influence of varying welding heat input. This study primarily investigates the thermal characteristics of the Submerged Arc Welding (SAW) process using a moving heat source model based on a Gaussian distribution. A methodology based on the Finite Difference Method (FDM) is developed and implemented using MATLAB to accurately estimate the thermal profile. The results show good agreement between the numerical and experimental data, with an overall error ranging between 6% to 9%, thereby confirming the accuracy and reliability of the proposed numerical model. Finally, the results emphasize the critical role of welding parameters in shaping the thermal profile. It has observed that increasing the welding current, while maintaining a constant welding speed, has resulted in higher heat input and elevated weldment temperatures. The peak temperatures have recorded as 155 degrees C, 198 degrees C, and 210 degrees C at welding speeds of 0.60 m/min, 0.75 m/min, and 0.90 m/min, respectively. A maximum percentage difference of 7% has found between the experimental and numerical results, further validating the accuracy of the proposed model.
This study aims to design, optimize, and validate an all-electric propulsion system for a 25 m x 7 m aluminum catamaran ferry operating on a 25 km urban river route, focusing on power requirement prediction, battery sizing, energy-management strategies, and shore-charging integration. A slender-body resistance model, validated by cubic speed-power scaling, predicts calm-water resistance rising from 18.5 kN at 12 knot to 43.8 kN at the contractual speed 19 knot. Accounting for hull and drivetrain efficiencies yields a continuous shaft power requirement of 707 kW. Two 360 degrees Hydromaster D-series azimuth thrusters driven by 375 kW permanent-magnet motors are selected, providing 6 % continuous head-room and full redundancy while avoiding the mass penalty of a single 1 MW unit. Daily energy demand is quantified via a mode-based load matrix distinguishing propulsion, hotel, and intermittent peaks. Twelve round trips within a 17 h duty window consume 16.1 MWh for propulsion and 0.09 MWh for auxiliaries (16.2 MWh total). Limiting depth-of-discharge to 80% and reserving 20% state-of-charge for emergencies yields a 20.3 MWh lithium-iron-phosphate battery bank (204x100 kWh modules; 127 t, 68 m(3)) fitted amidships. Opportunity charging during each 25 min turnaround with a 6 MW liquid-cooled DC connector restores 1.7 MWh per call, maintaining the pack between 40% and 80% SOC and eliminating the need for 20-48 MW fast-charge infrastructure. This paper applies a Genetic Algorithm (GA) to optimize the decision vector P-thr, C-bat, P-chg, yielding a 12 % reduction in daily energy consumption compared to the baseline design. Convergence behaviour, optimal parameter values, and trade-offs between energy and capital cost are presented. Load-levelling strategies-radar standby, demand-controlled ventilation, and regenerative braking-trim hotel consumption by up to 15 % and reduce peak inverter currents. Sensitivity analysis shows that lowering service speed to 17 knot cuts daily energy by 23%, highlighting the trade-off between timetable and shore-power investment. By integrating resistance prediction, thruster selection, battery sizing, and charging strategy into a single framework, this research demonstrates the technical and operational feasibility of zero-emission river ferries and provides a repeatable methodology for future deployments in similarly constrained waterways.
By clarifying the impact of thermal radiation and induced magnetisms, this study explains the heat transformation analysis on ferromagnetic hybrid nano fluid dynamics. When heat transfer occurs in the presence of generated heat within the boundary layer, the induced magnetic field is taken into account. Heat generation and fluid thermal analysis are thought to be important within the boundary layer (BL) in order to standardize the dynamics process. PDEs, or partial differential equations, are used to describe the model. Ordinary differential equations (ODEs) are a further transformation of PDEs. The set of ODEs has been investigated using the spectrum relaxation method (SRM). The SRM is an iterative method for solving differential equations that makes use of the Gauss-seidel technique notion. It is observed that a higher Prandtl number causes the velocity and temperature to decrease. The thickness of the momentum BL is significantly influenced by the induced magnetic field. Together with thermal BL thickness, it was found that heat generation and thermal radiation increased momentum. Applications of this research can be found in the automotive and thermal engineering sectors. It is observed that the new analysis concurs with earlier publications.
This article conducts a detailed semi-analytical study on the steady flow of micropolar nanofluid over an inclined elongating sheet under multi-slip effects. This study examines the impacts of magnetic fields, heat source, chemical reaction, thermal radiation, and momentum, thermal, and concentration slip to model real-world systems for improved heat and mass transfer in key industrial applications. Similarity transformations convert the governing equations into nonlinear Ordinary Differential Equations (ODEs). The Homotopy Analysis Method (HAM) is used for numerical solutions. The results for the micropolar nanofluid's velocity, microrotation, temperature, concentration, friction factor, and mass and thermal transmission rates are presented pictorially and analyzed quantitatively. Findings reveal that enlarging thermophoresis, thermal source, radiation, and Brownian motion factors enhance the thermal distributions of the micropolar nanofluid flow. The validity of the results is confirmed through comparison with existing literature, demonstrating strong agreement. This study provides valuable insights into non-Newtonian fluid behavior and highlights the effectiveness of HAM-based numerical techniques in solving boundary layer problems.
This study investigates non-similar nonlinear thermal convection of a Buongiorno nanofluid through a Darcy-Forchheimer porous medium-an important problem for accurately modelling high-velocity thermal systems where Brownian motion, thermophoresis, and inertial porous-media effects coexist. It further highlights that the governing two-dimensional PDEs are solved using the second-order accurate Keller Box Method, validated against known special cases. The discoveries offer fresh perspectives on the behavior of nanofluids in porous media, contributing to a deeper understanding of heat, mass transfer, and fluid dynamics. It is observed that with increasing Darcy number, there is a substantial hike in velocity, but temperature and concentration decay; conversely, as the Forchheimer number increases, velocity is decreased; however, temperature and concentration profiles are elevated steadily. Specific and quantitative numerical results show that increases in nanoparticle Brownian diffusion Nb elevating temperature profiles by up to similar to 18% and reducing concentration by similar to 12%, thermophoresis Nt intensifying thermal fields by similar to 20% while lowering near-wall velocity, and higher Darcy Da and Forchheimer Fs numbers reducing near-wall momentum by 10-15% but enhancing thermal and concentration layers by up to 17%. This current study has practical implications for enhancing the design and optimization of cooling systems, electronic thermal management, and power systems in situations where accurate temperature regulation and effective heat transport are essential. By addressing the current research gap, this study makes major advances in the fields of thermal sciences and nanofluid technology dynamics, the novelty of simultaneously integrating Buongiorno's nanofluid theory with the nonlinear Da-Fs model in a non-similar convection framework-advancing beyond earlier studies that considered these mechanisms separately and were restricted to ODE formulations.
A thorough computational analysis of the nonlinear, steady-state, laminar convective boundary layer flow of an incompressible Buongiorno nanofluid across an elongating sheet with several slip effects is conducted. This research is important as it models realistic industrial and biomedical applications where slip conditions occur at surfaces, such as in microfluidic devices. Understanding these effects enhances control over heat and mass transmission. The governing PDEs are transformed into a system of non-linear ODEs using appropriate non-similar transformations. The flexible Keller Box technique for second-order accurate implicit finite-difference is used. An excellent correlation is obtained when validating the present results against previous research results available in the literature, and the error analysis is also examined. The novelty of the present work lies in its unique incorporation of simultaneous multiple slip effects into the analysis of Buongiorno's nanofluid flow over a stretching surface. It provides new insights into how combined slip conditions influence nanofluid transport characteristics. The study addresses the gap in existing literature by analysing the combined impact of slip conditions on Buongiorno's nanofluid. It also fills the void in understanding how these slip effects jointly influence transport phenomena past a stretching surface. Implications of velocity, thermal, and concentration slips are illustrated graphically. Additionally, tabular values of the skin friction, Nusselt number, and Sherwood number are also given. Computations show that the velocity, temperature, and concentration profiles rise with an increase in the velocity slip. However, when the thermal slip is elevated, velocity, temperature, and concentration profiles decline, and the thinner thermal boundary layers reduce thermal and concentration gradients near the surface, diminishing fluid velocity. With greater concentration slip values, the velocity profile is enhanced; however, temperature and nanoparticle concentration both decay. The findings indicate that slip parameters play a crucial role in modulating flow behaviour under practical slip conditions.
This study aims to investigate the comparison of steady and unsteady MHD mixed convective nanofluid flow over a cylinder, taking into account various factors, including slip conditions, heat and mass transfer, heat generation, stretching ratio, thermal radiation, curvature, viscous dissipation, and chemical reactions. The analogous transformation technique is employed to transform nonlinear PDEs into a system of coupled ODEs, which are then solved using the Runge-Kutta fourth-order approach. The influences of numerous relevant parameters on the velocity, thermal, and concentration boundary layers (BLs) are illustrated graphically. Furthermore, the shear stress coefficient, Nusselt number, and Sherwood number are calculated for steady and unsteady flow conditions. The findings reveal that unsteady flow substantially influences the skin friction coefficient and the rate of mass transfer. Notably, the slip effect enhances these processes compared to steady flow; conversely, a contrary movement is observed in the heat transfer rate. It is observed that in unsteady flow conditions, the skin friction coefficient increases by 0.34%, and 0.04%, respectively due to the increase of power-law index and curvature; the Nusselt number decreases by approximately 0.2%, and 0.02% for increasing values of thermophoresis, and Brownian motion; as well as the Sherwood number decreases about 0.08%, and 0.05%, respectively for rising values of Schmidt number, and chemical reaction compared to steady flow. This research presents significant new insights into the thermal behavior of viscoelastic fluids, which have the potential to enhance heat transfer methodologies in industrial coating systems, chemical reactors, and polymer extrusion processes.
The present paper aims to investigate the effect of thermal diffusion in a free convective, radiative, viscous, chemically reacting, incompressible, and unsteady MHD flow past an exponentially accelerated moving inclined plate submerged in a porous medium. The fluid is taken as optically thick and non-gray. A uniform magnetic field is applied in the transverse direction of the plate. The ramped temperature effect is also considered. The radiative heat flux that appears in the energy equation is described by the Rosseland approximation method. A closed form of the Laplace transformation technique is adopted to obtain analytical solutions to the non-dimensional governing equations. A detailed discussion on the effects of various governing parameters on the velocity field, temperature field, concentration field, Nusselt number, Sherwood number, and skin friction are analyzed using suitable graphs and tables. The investigation shows that the Soret effect hikes both concentration and velocity of the fluid. The chemical reaction effect upsurges the process of mass transfer from the plate to the fluid.
This paper is presented to analyze the task of assimilating parameters on MHD flow structure in a sloped pipeline while certain plate is disorderly heated. The impact of suction and heat generation is considered. The dictating liquid motion and energy equations are ascertained and corresponding expressions for thermal energy, liquid motion, fanning friction and stress flatten are acquired. In particular, the liquid motion behaves an increasing function of suction parameter and a decreasing function of magnetic parameter. This research is of special consequence in marine steam engineering, naval ships mooring and replenishment, medicine, and aerodynamics. Results are verified in special case with those existing in the literature.
In this paper, we have studied analytically the relationship between oscillatory free stream flow and twodimensional hydromagnetic oscillatory flows of a viscous, incompressible, and electrically conducting fluid past a porous, infinite limiting surface, as well as the temperature and magnetic fields that are associated with these flows. Both frequency-dependent effects and "long-time" effects, which call for impractically long channels to be observed in steady flow is studied with oscillating fluid. For many industrial processes, it is essential to comprehend the physics of oscillating flows of complex fluids in small channels. Many chemical and biochemical engineering operations depend on effective fluid mixing and efficient mass and energy transport. Our analysis was carried out using semi-analytical method in the neighborhood of epsilon. From the result obtained, we discovered that that variation of transient velocity are the same with those of the mean velocity. Also, the mean velocity increases when the limiting surface moves in the positive direction of the flow, whereas it decreases when it moves in the opposite direction and increase in magnetic parameter decreases the mean velocity and that the magnetic field is limited to only retardation. Other flow governing parameters were displayed using graphs and discussed accordingly.
The foremost empirical of this study is to research the flow of an Upper-Convected Maxwell (UCM) fluid including nanoparticles over an elongating surface on an inclined plane. The model analyzes the impression of an external magnetic field and investigates the impacts of linear thermal radiation, a heat source, and chemical processes under various slip situations. The Homotopy Analysis Method (HAM) is employed in order to work out the nonlinear equations that regulate the system through the provision of a robust framework for the accuracy of the solution. The principal findings are displayed in tabular and graphical formats. The findings indicate that an augmentation in magnetic field strength diminishes velocity profiles while enhancing both concentration as well as temperature profiles. Moreover, as the momentum slip consideration escalates, local Sherwood number and the local Nusselt number are diminish. The innovative discoveries are validated by comparisons with previous experimental and theoretical results, demonstrating practical applications in optimizing cooling systems, improving industrial heat exchangers, and increasing biotechnological processes such as wastewater treatment and pharmaceutical manufacture. Nanofluids and non-Newtonian fluids are being portrayed as highly effective solutions for next-generation cooling technologies as a result of this research, which provided a key insight into optimizing thermal management systems for advanced engineering applications.
The current study examines the Williamson fluid flow on a stretching surface under the effects of MHD and porous material. In addition, the effects of different characteristics such as heat source, viscous dissipation, joule heating effect and chemical reaction are examined. The influence of solutal stratification factors and temperature was also investigated. Partial differential equations are used to represent the problem's governing non-linear equations. After applying the required similarity transformations, these equations are transformed into a collection of non-linear ordinary differential equations. The Keller Box method is used to solve the resulting equations numerically. Plotting the velocity, temperature, and concentration graphs allows for the examination of the effects of different parameters. Additionally, local parameters are computed and compared with findings from earlier research; the results show compatibility. Profiles of velocity exhibit decreasing behaviour in case of Williamson, Magnetic, and Permeable parameter raises. Profiles of temperature exhibits the increasing tendency in case of Williamson, Magnetic, the effect of Radiation, Joule heating, Heat source and Eckert number whereas opposite trend is witnessed in case of Prandtl number, thermal stratification parameters raises. Concentration profiles enhances in case of Williamson, magnetic, permeability parameters and opposite behaviour is examined in case of chemical reaction, solutal stratification, Schmidt number parameters.
In this paper, a numerical study on the hydrodynamic performances of an autonomous unmanned vehicle (AUV) was carried out. For its propulsion, a model of a new seven-bladed propeller defined as stock propeller was made. Several numerical simulations were carried out, namely open water test, towing resistance test, and self-propulsion test. This study focuses on the thruster's ability to perform its task correctly for improved use. The examination of the propeller characteristics in open water test exhibits a better efficiency and the thrust can be improved by slightly adjusting the pitch distribution of the propeller. In the towing resistance test, wake behind the body was also investigated by studying axial velocity field in many transversal planes. Added to the self-propulsion test results, the evolution of the thrust magnitude in the wake by moving the thruster plane axially reveals that the required thrust level is reached far behind the actual position of the thruster disc. It is found that the ratio of thrusts with or without the presence of the body is equal neither to unity nor to the torque ratio.
The present study examines the stimulus of a magnetic field on the three-dimensional movement of Casson nanofluid over a stretchable surface embedded in a porous medium. The belongings of various constraints on the fluid dynamics are also analyzed. The governing nonlinear partial differential equations representing the fluid flow problem are converted into dimensionless ordinary differential equations using similarity transformations. These resulting ODEs are then solved numerically using the R. K. based Shooting method. The impact of various parameters on the flow profiles is illustrated through graphical representations. It is observed that the velocity profile decreases with an increase in the magnetic field number. Moreover, greater radiation parameter values lead to a rise in the distribution of heat and the corresponding layer thickness.
Transporting heat and mass in boundary-layer flows is crucial for various industries, including petroleum and agricultural engineering, gas turbines, nuclear power facilities, heat exchangers, cooling systems, and chemical processing. Understanding these processes is essential for advancing scientific knowledge and improving practical engineering applications across multiple fields. This study aims to investigate the effects of thermal and solute buoyancy forces on the fluctuating flow within a boundary layer over an upright permeable flat sheet with heat generation. This analysis requires modifying the nonlinear and time-varying partial differential equations (PDEs) to address the continuity, momentum, energy, and concentration balance equations. After developing a mathematical model, the explicit finite difference method (EFDM) is utilized to solve a set of nonlinear dimensionless partial differential equations and suitable boundary conditions (BCs). The EFDM technique is described step-by-step and tailored to the specific analyzed model. The stability, convergence, finding a suitable uniform meshing, steady-state condition, and code validation are conducted. This study investigates the distributions of velocity, temperature, and concentration influenced by physical forces, specifically buoyancy and heat generation. It provides a detailed analysis of the mean and local rates of the skin friction coefficient and heat and material transport. The findings demonstrate that fluid velocity rises as buoyancy increases, and increasing heat generation increases heat-mass heat transmission rates. The practical behavior results from the pressure gradient caused by thermal buoyancy force. Two novel linear regression equations with multiple variables are derived from the outputs. This study establishes a robust and adaptable framework to enhance understanding of boundary-layer flows across various practical applications. It leverages advanced modeling techniques, incorporates variable properties, employs unsteady analysis, considers surface porosity, and investigates the effects of heat generation and thermalsolutal buoyancy forces.
Many marine vessels and small unmanned air vehicles operate at low Re flow regimes. Due to their small size and low operational velocities, they face increased stall severity, which is a crucial challenge to overcome. Tubercle Leading Edge (TLE) aerofoils can be exploited to solve this issue. Akin to passive flow control devices, tubercles generate counter-rotating vortex pairs on aerofoils, with vorticity being proportional to amplitude to wavelength ratio thus augmenting lift, and delaying flow separation. Performance improvements such as reduced drag, reduced stall severity, and improved post-stall characteristics are achieved using TLE designs. This investigation experimentally and numerically is focused on the performance characteristics of three designed TLE aerofoils at a relatively low Re value of 1x10(5). Limited studies are available on this low Re flow regime, hence the novelty of this investigation. The aims were to build upon the literature and to determine the best TLE aerofoil variant for further investigation, development, and eventual system-level implementation in a small naval or air vehicle design. The TLE aerofoil models investigates, 'A4 lambda 25', 'A8 lambda 25', and 'A12 lambda 25' which specify the tubercle amplitude and wavelength in mm delivered weaker and delayed stall, reduced pre-stall drag, and improved post-stall lift. The 'A4 lambda 25' model offered the best combination of increased pre-stall lift, reduced pre-stall drag, and post-stall lift. Further investigation on the 'A4 lambda 25' variant's performance within the context of an engineered system is worthwhile for realizing its application in low Re flight.
This research paper explores the intricacies of heat and mass transfer in a vertical channel with immiscible fluids, delving into the dynamics of two-fluid flows. The study investigates the impact of variable viscosity and thermal conductivity on the transfer processes within the channel. Additionally, the incorporation of thermal slip effects is considered, adding a layer of complexity to the analysis. The Runge-Kutta sixth-order method, implemented through Mathematica ND Solve technics, ensuring accurate numerical simulations. An extensive examination of dimensionless velocity, angular momentum, energy, and diffusion is performed across all pertinent parameters, and the results are graphically illustrated to draw meaningful conclusions. This visual representation simplifies the comparison of transfer rates along the channel wall. Bar charts visually represent key elements of heat and mass transfer, including shear stress, the Sherwood number, and the Nusselt number, to make it easier to compare transfer rates along the channel wall. The outcome has shown that there is a significant effect of pertinent parameters on both heat and mass transfer.
