98%
921
2 minutes
20
A submerged finite cylinder moving under its own weight along a soft incline lifts off and slides at a steady velocity while also spinning. Here, we experimentally quantify the steady spinning of the cylinder and show theoretically that it is due to a combination of an elastohydrodynamic torque generated by flow in the variable gap, and the viscous friction on the edges of the finite-length cylinder. The relative influence of the latter depends on the aspect ratio of the cylinder, the angle of the incline, and the deformability of the substrate, which we express in terms of a single scaled compliance parameter. By independently varying these quantities, we show that our experimental results are consistent with a transition from an edge-effect dominated regime for short cylinders to a gap-dominated elastohydrodynamic regime when the cylinder is very long.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1039/c9sm02344e | DOI Listing |
Materials (Basel)
July 2025
School of Metallurgy and Environment, Central South University, Changsha 410083, China.
The formation mechanism of black streak defects in hot-rolled steel sheets was investigated to address the influence of the process parameters on the surface quality during the production of 304 stainless steels. Macro-/microstructural characterization revealed that the defect regions contained necessary mold slag components (Ca, Si, Al, Mg, Na, K) which originated from the initial stage of solidification in the mold region of the continuous casting process, indicating obvious slag entrapment during continuous casting. On this basis, a three-dimensional coupled finite-element model for the molten steel flow-thermal characteristics was established to evaluate the effects of typical casting parameters using the determination of the critical slag entrapment velocity as the criterion.
View Article and Find Full Text PDFCommun Eng
July 2025
School of Civil Engineering, Tsinghua University, Beijing, PR China.
Submerged floating tunnels (SFT) offer a promising solution for deep-water crossings and intercontinental transportation. However, current SFT designs struggle to meet the high structural performance demands associated with the harsh service environments while remaining economically viable, thus limiting their implementation in practice. Here, we propose a conceptual SFT design using a triple-chord trussed concrete-filled double-skin tubular (CFDST) hybrid structure, featuring CFDST chords and hollow steel tubular braces.
View Article and Find Full Text PDFSensors (Basel)
March 2025
Naval University of Engineering, Wuhan 430033, China.
This manuscript aims to optimize the acoustic scattering characteristics of underwater corner reflector linear arrays through simulation analysis and experimental validation, thereby enhancing their application efficiency in underwater acoustic countermeasures, particularly in terms of increasing acoustic echo intensity and reducing reflection blind spots. The acoustic scattering characteristics of submerged corner reflectors were meticulously simulated using the finite element method-boundary element method coupling technique, and the simulation results were rigorously verified through tank experiments. The study focused on the impact of the number of corner reflectors and their deployment angles on acoustic echo characteristics.
View Article and Find Full Text PDFMaterials (Basel)
February 2025
School of Civil Engineering, Southeast University, Nanjing 211189, China.
Understanding the dynamic response of cylindrical shells subjected to underwater explosion is crucial for designing safe underwater vehicles, especially in deep-water environments where the shell structures are prestressed by hydrostatic pressure. The complex combination of external loading crossing different temporal scales-from underwater explosive shock waves to bubble pulsation and hydrostatic pressure-results in a synergic damaging effect on the target structures. In this work, the dynamic responses and buckling failure mechanisms of deeply immersed (≥1300 m) cylindrical shells subjected to underwater explosion were investigated through a numerical approach using the finite element method.
View Article and Find Full Text PDFMicromachines (Basel)
July 2024
Department of Mechanical Engineering, Faculty of Engineering, University of Malta, MSD 2080 Msida, Malta.
In recent years, the immense potential for MEMS devices in the biomedical industry has been understood. It has been determined that, among their many plausible functions, their use may also extend to single human red blood cell diagnostics, whereby biomarkers of quantifiable magnitudes may be detected. Without a doubt, the mechanical and thermal specifications by which potential devices must be able to function are very strict.
View Article and Find Full Text PDF