The stability of hybrid nanofluids plays a crucial role in determining their thermophysical performance and long-term applicability in advanced thermal management systems. Experimental determination of nanofluid’s stability is often time-consuming, expensive, and influenced by multiple interacting physicochemical parameters. To overcome these limitations, this study investigates the colloidal stability of hybrid nanofluids using a numerical model based on the physics-informed Artificial Neural Network (ANN) integrated with Derjaguin-Landau-Verwey-Overbeek (DLVO) theory and Smoothed Particle Hydrodynamics (SPH) to predict the stability of hybrid nanofluids. Bayesian Regularization Artificial Neural Network (ANN) employed for reducing needs of extensive simulation, faster prediction of stability for new nanofluid compositions, and support optimization. By simulating Van der Waals attractions, electrostatic repulsion, Brownian diffusion, sedimentation, particle aggregation, and dispersion behavior produces a normalized stability score for ANN training under varying zeta potential, ionic strength, and nanoparticles size. A MATLAB-based SPH solver is implemented to track interparticle dynamics over time. A physics-informed dataset consisting of 5000 samples was generated using coupled DLVO and SPH simulations considering six governing physicochemical parameters: zeta potential, particle radius, Debye length, Hamaker constant, temperature, and surfactant concentration to predict hybrid nanofluid stability. Regression analysis showed a strong correlation between the predicted and actual stability scores with a coefficient of correlation $(R)$ of 0.9907. The developed model showed good predictive capability and generalization with the overall coefficient $(R^2)$ of 0.9808, root mean square error (RMSE) of 0.0234, mean absolute error (MAE) of 0.0174, and MAPE of 3.13%. The results provide knowledge to optimize the dispersion stability of Hybrid Nanofluids in Thermal and Biomedical Applications.
This study examines the flow of a water-based nanofluid containing $\text{Fe}_3\text{O}_4$ magnetized nanoparticles over an elongating surface, a problem of considerable importance in biomedical applications. The proposed nanoparticles are especially relevant to thermal energy systems, cooling technologies, and drug delivery. The analysis investigates the effect of magnetization on flow over an elongating surface embedded in a porous matrix. It also compares the structural behaviour of spherical and cylindrical nanoparticles. Thermal radiation and dissipative effects are considered because they enhance heat transport. Under the stated assumptions, the governing model is transformed into a non-dimensional system of ordinary differential equations, which is solved numerically. A Runge-Kutta shooting method, implemented through MATLAB’s bvp4c function, is used for the computations. The influence of the governing parameters on the flow characteristics is presented graphically and discussed physically.
This study examines time-dependent nonlinear free convection of a nanofluid in an upright tube, accounting for Brownian motion and thermophoresis. The governing momentum, energy, and nanoparticle volume fraction equations are formulated. Closed-form solutions for the flow configuration are obtained using direct integration and the method of variation of parameters, while an implicit finite difference scheme is employed to solve the highly nonlinear unsteady equations numerically after discretization. The effects of key parameters on velocity, temperature, mass diffusion, nanoparticle concentration, skin friction, and heat and mass transfer rates are presented and discussed with the aid of graphs. To verify the accuracy of the analysis, the numerical results are compared with the analytical solutions for the classical case at large times, showing excellent agreement. The results indicate that nonlinear density variation enhances fluid velocity in the vertical tube because axial buoyancy, geometric confinement, and particle motion are strongly coupled. These findings may be useful in engineering, medical, and technological applications that require elevated temperatures, including electrolytic cells, DNA testing, and thermal scheduling or process control.
In late October 2025, a category-5 Hurricane named Melissa devastated the island nation of Jamaica. From 06 UTC on 25 to 06 UTC on 28 while Melissa was over the open Caribbean Sea, simultaneous measurements of the maximum sustained wind speed (VMAX), the minimum sea-level pressure (MSLP), and the radius of max wind (RMW) in every 3-hour interval for the isotach or equal wind speed analysis charts were made by the Regional and Mesoscale Meteorology Branch (RAMMB, see RAMMB: TC Real-Time: Currently Active Tropical Cyclones). The aim of this study is to develop the ranges of the atmospheric vorticity associated with this tropical cyclone and to relate appropriate values to the newly proposed hurricane classification in 2020 using the MSLP as published in the Bulletin of the American Meteorological Society. During the period as stated above, Melissa’s intensity increased from 17 to 71 $\text{ms}^{-1}$. Data analysis indicates that $\text {VMAX}=-0.662 \times \text {MSLP} +683$ with a coefficient of determination, $R^2=0.99$. During the same period, overwater relations between the RMW in km, and VMAX and MSLP are $\text {RMW}=-2.05 \times \text{VMAX}+162$ with $R^2=0.99$, and $\text {RMW}= 1.175 \times \text{MSLP} - 1068$ with $R^2=0.97$, respectively. Using these relations, it is found the $\text {Vorticity}=-0.0756 \times \text{MSLP}+75$ with $R^2=0.85$. The implication is that $Vr = \text {VMAX}[(-2.05 \text{VMAX}+162)/r]^{0.5}$, here $Vr$ is the wind speed at the distance $r$ from the storm center. Finally, based on the relation between the isotach and the wind-induced storm surge as proposed by the author in 2025, it was hindcast that the potential storm surges around Jamaica during onshore wind conditions could have been ranged from 3.6 to 4.9 m or approximately 12 to 16 feet depending on whether the wind directions were directly onshore or at an angle.
The present paper examines the heat and mass transfer characteristics of magnetohydrodynamic flow of a couple-stress fluid past an infinite vertical porous plate embedded in a porous medium. The permeability of the porous medium and suction velocity are time-dependent and oscillatory. The governing partial differential equations of flow are transformed into ordinary differential equations by separating steady and oscillatory parts. The results are depicted graphically to show variations in fluid velocity, temperature, and concentration profiles for various flow parameters. Additionally, variations in shear stress at the plate, the Nusselt number, and the Sherwood number are presented through tables.
The growing need to use effective thermal management in the industry, renewable energy systems and effective cooling technologies, drives the need to develop high-performance heat transfer fluids. A promising solution is ternary hybrid nanofluids, which consist of several nanoparticles and improve the ability of conventional fluids in terms of heat and mass transfer. This study investigates the two-dimensional, convective magneto hydrodynamic (MHD) boundary layer flow of ternary (Cu-Fe3O4-SiO2/H2O) and hybrid (Cu-Fe3O4/H2O) configuration of nanofluids across a convectively heated stretched sheet under the influence of magnetic field. The governing equations incorporating convective boundary conditions are solved using the Runge-Kutta-Fehlberg (RKF-45) algorithm combined with the shooting method. Various parameter values of Cu-Fe3O4-SiO2/H2O and Cu-Fe3O4/H2O nanofluids are studied to analyse velocity and temperature profiles. It is found that the velocity downgrades with an augmentation in nanoconcentration while enhances with stronger buoyancy effects (G). The temperature profile upsurges with rising nanoconcentration magnetic parameter (M), radiation parameter (Rd), heat source parameter (Qs), Eckert number (Ec), Biot number and Forchheimer parameter (fs). Also, entropy generation (Ns) intensifies near the stretching sheet as M and Rd increase. The Nusselt number enlarges with increasing while it reduces under the influence of G, M, Rd and Ec. These findings provide valuable insights for optimizing thermal systems, improving energy efficiency, and reducing operational costs in engineering applications.
During a tropical cyclone, it is common for the dominant wave period to exceed 10 seconds. Therefore, shoaling wave conditions occur at approximately from the water depth shallower than 40 meters in coastal waters. In September 2020, Hurricane Sally impacted the National Data Buoy Center (NDBC) Buoy 42012 located at the water depth of 23.5 m. The measurements of marine meteorological-physical oceanographic (met-ocean) parameters from this buoy provide us an opportunity to investigate the wind-wave interaction under shoaling wave conditions. In this study, analytical formulas are presented to estimate the met-ocean parameters for the wind-wave interaction. They are: the depth of shoaling waves, the aerodynamic roughness length, the friction velocity, the wind speed at 10 m, the downwind turbulence intensity, and the drag coefficient.
In this work, the effects of fractional time derivatives on the thermal and flow characteristics of an incompressible, magnetized dusty fluid in a vertical slit microchannel are examined. Temperature and velocity profile dynamics under different magnetic intensity, fractional order, and wall-slip conditions are investigated using both Caputo-Fabrizio (CF) and Atangana-Baleanu in Caputo (ABC) fractional models. The Laplace transform is used to solve the governing equations analytically, and the Riemann Sum Approximation (RSA) is used to invert the equations numerically. The findings indicate that fractional parameters and magnetic fields have a major effect on fluid velocity and heat transmission. In comparison to the CF model, the ABC model continuously displays smoother temperature and velocity profiles, indicating higher memory and damping effects. The study shows that skin friction and heat transfer rate are critically influenced by fractional order, magnetic parameters, and particle inertia. The results improve our knowledge of dusty MHD flows in microscale applications like industrial processing, medicinal devices, and energy systems. A study comparing the CF and ABC models of magnetized dusty flow in a slit microchannel with slip and volumetric heat generation has found consistent, quantifiable model differences. The ABC model predicts larger memory-induced damping, such as higher skin friction and lower Nusselt numbers, compared to the CF model.
The problem in the reflection of surface water waves that progress obliquely towards a bended plate, in infinite depth water, is considered with the help of linear theory. Here a simplified method is applied essentially on the perturbation technique, together with the application of the expansion of Havelock [1] of the potential of the water waves to address the problem. Considering two particular shapes of the bended plate, the corrections to the velocity potential and reflection coefficient of first order are enumerated.
This study applies the Adaptive Multi-step Differential Transform Method (AMsDTM) to analyze magnetohydrodynamic (MHD) boundary layer flow and heat transfer of an Double subscripts: use braces to clarify -water nanofluid over a porous wedge with variable viscosity under a convective surface boundary condition. Using similarity transformations, the governing nonlinear partial differential equations are reduced to ordinary differential equations, which are then solved approximately through AMsDTM coupled with Newton’s iteration. The effects of the variable viscosity parameter, magnetic field strength, Biot number, buoyancy parameter, nanoparticle volume fraction, and suction parameter on the velocity and temperature profiles are examined in detail. Results are illustrated graphically to demonstrate the influence of these parameters on the flow and thermal fields. A comparison with existing numerical findings shows excellent agreement, confirming the accuracy and robustness of the present method.
The development of space shuttles and high-performance military aircrafts has made the study of turbulent flow in separated regions a key area of research. Researchers are also interested in turbulent flow under transonic and supersonic conditions, particularly when it separates suddenly and expands after the cross-section of the larger duct increases rapidly. Two regions where the shear layer forms are the separated flow and the main flow. The split streamline reattaching to the duct causes significant drag and creates a recirculation zone where the pressure is lower than in the surrounding air. This study investigates the use of quarter-circular ribs to regulate base pressure as a passive control method, where the shear layer hits the straight part of the rib and the curved part is downstream. Computational simulations investigate how the rib radius and placement near a backward-facing step influence flow behavior, including recirculation and vortex formation. In the study, the inertia parameters considered were a Mach number of and the nozzle pressure ratio (NPR) in the range of 3 to 11 . The geometrical parameters considered were the area ratio , the cross-sectional area of the duct-to-nozzle exit, and the length-to-diameter ( ) ratio, ranging from 1 to 6 . The quartercircle radius considered was , and 3 mm , and the ribs were located at , and 2 . The goal is to identify the optimal rib geometry and location that maximizes aerodynamic efficiency. The results show that the optimum rib radius and locations are 3 mm and . The rib radius of 1.5 mm does not show any definite pattern. In contrast, the 3 mm rib radius exhibits a progressive increase in the base at various locations within the duct. Hence, a 3 mm rib radius seems to be the best option if the application is to reduce the base drag to a considerable level.
Fuzzy hypothesis testing is a useful framework for addressing statistical inference problems involving vague or imprecise data. In this paper, we enhance the interpretability and consistency of such tests by introducing a ranking-based approach for comparing trapezoidal fuzzy numbers. The method integrates a geometric and information-sensitive order relation into the defuzzification stage of fuzzy p-values, improving the decision-making process under uncertainty. This modification is applied within an existing fuzzy hypothesis testing structure, where fuzzy null and alternative hypotheses are evaluated, and the resulting p-values are interpreted through ranking rather than arbitrary thresholds. Two numerical examples are provided to illustrate how the proposed ranking step affects the final decision, showing that different defuzzification strategies can lead to distinct conclusions. The proposed approach maintains mathematical rigor while offering a more intuitive interpretation of fuzzy test outcomes. The findings suggest that selecting a robust ranking mechanism is crucial when testing hypotheses based on fuzzy data, and they open new perspectives for applying fuzzy statistics in fields such as engineering, medicine, and social sciences.
Overwater friction velocity is a vital parameter in air-sea interaction, particularly for the momentum transfer across the air-sea interface including the generation of waves and drift currents ( ). From operational viewpoints of geophysical fluid mechanics and dynamics such as the analysis and prediction of oil spill trajectory, is an important parameter. In order to understand the characteristics of and , both wind speed ( at height of 10 meters) and wave parameters including the dimensionless wave steepness ( , here is the significant wave height, is the dominant wave length and is the dominant wave period) must be taken into account. However, only few direct simultaneous measurements of all 4 parameters, and are available in the literature, particularly during tropical cyclones (TCs). In this paper, based on wave data for and indirect estimation of normalized friction velocity , during Hurricanes Katrina, Ivan, and other TCs, it is found that +0.013 and . The proposed explicit relation between the normalized friction velocity and the wave steepness is verified by both the direct measurements during the Southern Ocean Waves Experiment and the independent wind gust or turbulence intensity method during 6 hurricanes. The explicit relation between the normalized surface current and the wave steepness is validated by the direct measurements during Hurricane Ivan.
Inspired by the Cessna A37, the present article offers a thorough aerodynamic assessment of a model aircraft carried out under controlled subsonic settings in a systematic wind tunnel testing program. Over several wind speeds (5 to 25m/s) and angles of attack (AOA), the study concentrated on important aerodynamic characteristics like lift, drag, moments, and stability. While at an AOA of 15 deg, lift increased greatly from 0.54 to 1.33, accompanied by a drag coefficient rise from 0.0 to 0.6, at a zero-degree AOA, the lift coefficient ranged from –0.39 to 0.98. Especially at an AOA of 25 deg, lift increased to a maximum of 2.79 and a matching drag coefficient of 2.64. These differences were investigated to find their reliance on AOA and wind speed. The results highlight the aerodynamic efficiency of the model and possible relevance for subsonic flight, therefore providing important new perspectives on lift-to-drag performance ratios over operational situations. The study concludes by highlighting the model’s general usefulness and viability in a number of aeronautical applications, while also highlighting critical design issues such as construction techniques and material selections that are critical to optimizing the model’s performance for both manned and unmanned aircraft operations.
The present study investigates solution to the problem of magnetohydrodynamics free convective flow past an inclined porous plate in presence of the heat source, Soret effect, Dufour effect and chemical reaction. To analyze the flow model, we transform it into a system of partial differential equations. We then employ the bvp4c method in MATLAB to obtain numerical solutions for this system. Numerical results show that the chemical reaction, thermal radiation, angle of inclination, Soret and Dufour effects possess a major impact on the heat and mass transfer of the fluid. The results of this study could be relevant in the fields of chemical industries, chemical engineering, and petroleum engineering. Velocity, temperature and concentration distribution are presented graphically for various emerging physical parameters like Soret number, Dufour number, Prandtl number, radiation and the heat source.
In the context of rising fuel prices, car manufacturers need to find energy-saving solutions. Reducing fuel consumption helps decrease pollution and save fossil fuels. Air resistance affects the performance of the vehicle, especially when moving at high speeds. This drag increases with speed and causes air turbulence, creating a high-pressure zone behind the car. Although the car has been designed with optimal aerodynamics, it still has limitations in terms of style and functionality. To address this, vortex generator technology is used to reduce drag and prevent airflow separation, improving performance. This study optimizes drag on the Honda Civic Type R model by changing the angle of air contact and using Simcenter Star CCM+ software to simulate aerodynamics.
An analytical investigation is carried out to examine the stability of a horizontal, fluid-saturated, rotating anisotropic porous layer that is heated from below and cooled from above. The analysis is conducted under the assumption that the fluid and solid phases are not in local thermal equilibrium. The momentum equation is based on Darcy’s model, modified to include the Coriolis term to account for rotational effects. The energy equations are formulated using a two-field model, representing the thermal behavior of the solid and fluid phases separately, with each incorporating anisotropic thermal conductivity. It is assumed that the temperatures of the solid and fluid phases are equal at the bounding surfaces. Linear stability theory is employed to determine the critical Rayleigh number and wave number for the onset of convection. Through graphical analysis, the effects of anisotropic permeability and rotation on convective instability are illustrated. The results reveal that thermal anisotropy and rotation act to stabilize the system, while mechanical anisotropy and an increased conductivity ratio have a destabilizing influence.
In this investigation, compressive and rarefactive solitons are demonstrated to exist in a plasma model that includes unmagnetized weak-relativistic positive ions, negative ions, electrons, electron beam and positron beam. For these weakly relativistic non-linear ion-acoustic waves in unmagnetized plasma with electron inertia and relativistic beam, the existence of compressive and rarefactive soliton is investigated by deriving the Korteweg-de Vries (KdV) equation. It has been observed that the amplitude and width of compressive and rarefactive solitons vary differently in response to pressure variation and the presence of electron inertia. The research determines the requirements that must be met for the existence of the nonlinear ion-acoustic solitons. The fluid equations of motion governing the one-dimensional plasma serve as the foundation for the analysis. Various relational forms of the strength parameter (ε) are chosen to stretch the space and time variables, leading to a variety of nonlinearities. The findings can have implications not only for astrophysical plasmas but also for inertial confinement fusion plasmas.
