The Archimedes spiral wind turbine (ASWT), as a novel type of horizontal-axis wind turbine, is well suited for remote islands. To explore the aerodynamic performance and coupling gain effect of ASWT array, a three-dimensional numerical simulation was carried out using the computational fluid dynamics (CFD) method. The influence of arrangement, relative spacing, and rotation configuration on the performance of a double-unit array and triangular array is studied. The results demonstrate that, in parallel arrangements, the double unit achieve higher performance than an isolated ASWT within a specific range of parallel spacing. However, the effect of performance improvement gradually diminishes as the parallel spacing increases. In tandem arrangements, the upstream unit performance remains largely unaffected when tandem spacing exceeds 5 D, while the downstream unit’s performance declines notably with reducing tandem spacing. The downstream unit in reverse rotation configuration accrues more energy than its counterpart operating at the co-rotation configuration. In triangular arrangements, the reverse rotation configuration can achieve better performance due to the meshing effect between the wake of the upstream ASWT and the downstream ASWT. This configuration allows the array system to maintain a higher maximum power output within a smaller spacing. The research results can provide a basis and reference for designing the layout scheme of a multi-unit ASWT power station.

Postural Orthostatic Tachycardia Syndrome is characterized by an excessive increase in heart rate during postural changes without significant blood pressure alterations, often accompanied by symptoms such as dizziness, fatigue, and palpitations. While prior studies have explored potential mechanisms, the precise etiology and pathological basis of Postural Orthostatic Tachycardia Syndrome remain unclear, leading to treatments focused on symptom management rather than addressing root causes. This study employs a hemodynamic fluid-structure interaction model (using existing clinical data) to investigate the roles of hypovolemia, vascular dysfunction, and autonomic nervous system dysregulation in Postural Orthostatic Tachycardia Syndrome pathogenesis. Computational results revealed that hypovolemia reduces cerebral blood flow by approximately 100 mL/min due to a 30% decrease in blood volume, while vascular dysfunction—marked by a 50–100% increase in arterial stiffness—further diminishes cardiac output and cerebral perfusion. These conditions trigger compensatory tachycardia through autonomic feedback mechanisms. Our findings demonstrate that an insufficient cerebral blood supply, driven by hypovolemia and impaired vascular compliance, combined with autonomic dysregulation, underlies the hallmark tachycardia in Postural Orthostatic Tachycardia Syndrome. This mechanistic insight provides a foundation for targeted therapeutic strategies, emphasizing the need to address blood volume management, vascular elasticity, and autonomic balance to improve clinical outcomes.

Deep-sea exploration relies heavily on autonomous underwater vehicles (AUVs) for data acquisition, but their operational endurance is limited by battery constraints. The Archimedes spiral hydrokinetic turbine (ASHT), as a novel type of horizontal-axis hydrokinetic turbine, has emerged as a promising solution for the harnessing of localized energy in the deep sea to power AUVs. This study explores the application of winglets on an ASHT to enhance its performance through computational fluid dynamics (CFD). The analysis focuses on the effects of the winglet angle and height ratio on the power and thrust, as well as the pressure distribution and flow characteristics. The findings indicate that strategically designed winglets, particularly those with angles greater than 90° and larger height ratios, can significantly improve the ASHT’s performance. This enhancement can be attributed to the winglets’ capacity to effectively reduce tip loss and expand the turbine’s swept area, thereby enhancing power extraction. The optimal configuration, determined at a winglet angle of 135° and a height ratio of 12–14%, demonstrates significant enhancements, including a minimum increase of 12.0% in power efficiency compared to the original ASHT. However, the study also acknowledges potential challenges; winglets with larger angles and height ratios may lead to increased load fluctuations, which require careful structural considerations. This study provides valuable insights into the design and optimization of ASHTs for deep-sea power generation, thereby contributing to the advancement of sustainable energy solutions for AUVs.

Atmospheric aerosol quenching at a high speed is a new quenching process. Each condition is equivalent to a new type of quenching medium. In this study, quenching experiments with atmospheric high speed aerosol were carried out. In this paper, the surface integrated heat transfer coefficient of the specimen during the quench process is reverse solved with FEM software DEFORM and FORTRAN program based on nonlinear estimation method respectively, and the results of inverse heat transfer calculation are analyzed.

Ocean current energy is abundant, yet its exploitation is severely constrained by the low-velocity conditions typical of most marine environments, where conventional lift-type turbines exhibit poor self-starting capability and low efficiency. This review provides the first comprehensive synthesis of research on free-stream Archimedes spiral hydrokinetic turbines (ASHTs), a class of drag-dominated rotors developed specifically for low-velocity kinetic energy harvesting. A unified classification is introduced, dividing ASHTs into single-blade long-axis (SL-ASHT) and three-blade short-axis (TS-ASHT) configurations. The energy conversion mechanisms, governed by pressure difference and hydrodynamic force synergy within helical passages, are elucidated, and the influence of critical geometric parameters is assessed. For SL-ASHTs, the analysis highlights exceptional self-starting capability (cut-in velocity: 0.1 m/s), a starting torque coefficient of 0.52, a maximum power coefficient of 0.51, and passive yaw adaptability that limits efficiency variation to below 2% over yaw angles of 0–40°. TS-ASHTs feature a compact architecture and higher rotational speed, facilitating direct generator coupling. With variable blade-angle distributions, thin airfoils, and non-uniform gap ratios, the power coefficient reaches 0.312. Performance-enhancement measures, including multi-parameter optimization, ducts, and winglets, deliver power gains of up to 35%, 122%, and 12%, respectively. This review further identifies critical barriers to engineering deployment: sediment erosion, cyclic fatigue, performance degradation under large yaw angles, and wake interactions. Future priorities include multi-objective optimization, advanced materials and flow control, full-scale sea trials, multiphysics coupling, array layout optimization, and hybrid energy system integration. By establishing a coherent classification and performance-evaluation framework, this work demonstrates that ASHTs offer strong potential as core devices for large-scale utilization of low-velocity ocean current and river hydrokinetic energy.