In this study, free, forced, vibrational, and conjugate convection within a stepped chamber are examined. The forced convection arises from the multi-level shear flows induced by the lid-driven upper walls, while the conjugate convection results from the presence of finite-length solid walls attached to the lower-left and upper-right outer edges of the domain. Several solid-wall materials are considered, including slate tiles, concrete tiles, clay tiles, and plastic tiles, and a sinusoidal vibration is imposed within the flow domain. The cavity is filled with anisotropic porous elements, while the working suspension consists of micropolar nanofluids. The governing problem is solved via the PIP-FVM, and the resulting heat and mass transfer rates are correlated using third-order polynomial expressions in terms of the permeability ratio and solid wall thickness. The key outcomes demonstrate that, in the case of pulsating convection, the raising in the Reynolds coefficient from 10 to 500 causes an augmentation in the heat transfer rate of up to 709.06
The problem of fracture heat transfer and fluid flow through intersecting fractures in rock and soil is important in geothermal energy exploitation, but the integrated effects of ternary hybrid nanofluids and magnetic fields have not been well studied. This paper fills this gap by analysing a three-dimensional rectangular channel with a main horizontal fracture intersected by three equally spaced angled fractures. In COMSOL Multiphysics, the ternary hybrid nanofluid (CuO + MoS2 + Fe3O4) was modelled using the conjugate heat transfer interface, and the coupled conduction and convection equations were solved. The seven sensitivity parameters studied are: Reynolds number (10–40), volume fraction (1–10 (30^∘, 45^∘, 60^∘,) and fracture inclination angle ( (30^∘ – 120^∘) . The results indicate that the velocity change V% along the midline of the fracture increases slightly with Reynolds number (from ∼ 41% to ∼ 45% for Re=10 to 40 ) due to the normalisation of V% by the inlet velocity, whilst the temperature change ( T% ) decreases with increasing Reynolds number due to a decreasing residence time. The nanoparticle concentration and the shape factor were increased to improve the heat transfer efficiency. The thermal performance was maximised at 10 (n=5.7). The magnetic damping reduced the velocity but enhanced the thermal absorption, which were highly dependent on the Hartmann number and the field angle. The larger aspect ratios decreased T% at a fixed Reynolds number. The wider aperture increases the transverse diffusion distance from the walls to the centreline, so the centreline fluid is less thermally developed at the outlet. Multiple linear regression models for V% and T% had coefficients of determination (R^2) of 0.55 and 0.95, respectively.
Structural damping is critical to the design and health monitoring of composite structures. The short-term response of low-velocity impact occurs within a narrow time window, yet its damping dependence remains to be fully quantified. This work numerically investigates the damping-dependent impact damage behavior of composite laminates, focusing on material damping and contact damping. This study lies in three aspects. First, Rayleigh damping is assigned separately to the layer and inter-laminar materials, and allowing material damping and contact damping to be treated distinctly. Second, a progressive damage framework is established, the dynamic response of damage dissipation energy (DDE), viscous dissipation energy (VDE), and friction dissipation energy (FDE) are tracked separately. Third, the damping dependence of these dissipation energies is quantified at the millisecond scale under low-velocity impact. A validated finite element model is established and verified by X-ray experiments. The results show that damping has negligible effects on impact force and displacement within the narrow loading window. In contrast, varying damping parameters lead to up to 10.85
Cantilever plates with systematically cut slots show strong potential for piezoelectric energy harvesting in low-frequency vibration environments. This study investigates 19 slotted aluminium cantilever plate configurations through finite element simulations and physical experiments, establishing that slot geometry directly controls the number of natural frequency modes below 1000 Hz. The five-slot square plate (Case 11) achieves 23 modes and a 4.64 times voltage improvement over the plain plate. However, the 19-point discrete experimental grid covers only a small fraction of the continuous three-dimensional design space defined by slot count, slot length, and slot width. To systematically explore this space without running thousands of costly ANSYS simulations, a neural network surrogate model is trained on the 18 validated configurations using leave-one-out cross-validation, with the architecture and regularization selected by a cross-validated grid search, achieving a mean absolute error of 2.67 modes overall and 2.08 modes in the high-performance region (20–23 modes). A genetic algorithm then searches the continuous geometry space through surrogate evaluations, both without restriction and within a trust region around the training data. Inside the data-supported region, the optimum lies next to Case 11 (24.2 predicted modes), which is consistent with the experimental result, and a ± 5
The Lattice Boltzmann Method (LBM) has emerged as a robust computational framework for analyzing complex heat transfer phenomena influenced by magnetic fields. This review consolidates recent advancements in the study of magnetohydrodynamic (MHD) convection using LBM-based approaches. The existing body of research is systematically examined to identify modeling strategies, boundary conditions, and numerical schemes applied across different convective regimes. The literature is broadly organized into three domains (natural, forced, and mixed convection) allowing for a comparative assessment of flow behavior and thermal characteristics under magnetic effects. A synthesis of published results reveals that the intensity of convective heat transfer increases with higher nanoparticle concentrations and Rayleigh numbers, while stronger magnetic fields, represented by elevated Hartmann numbers, tend to suppress fluid motion and reduce thermal transport. These findings underscore the dual role of magnetic fields as both regulators and inhibitors of convection, highlighting their potential in thermal management and engineering design applications.
