infrastruktura: Cavitation

Evidence: 100 • authority: 72

Cavitation in fluid mechanics and engineering normally is the phenomenon in which the static pressure of a liquid reduces to below the liquid's vapor pressure, leading to the formation of small vapor-filled cavities in the liquid. When subjected to higher pressure, these cavities, called "bubbles" or "voids", collapse and can generate shock waves that may damage machinery. As a concrete propeller example: The pressure on the suction side of the propeller blades can be very low and when the pressure falls to that of the vapour pressure of the working liquid, cavities filled with gas vapour can form. The process of the formation of these cavities is referred to as cavitation. If the cavities…

Evidence: 42 • authority: 88

Evidence: 42 • authority: 80

Evidence: 42 • authority: 80

Evidence: 42 • authority: 92

Regulation of ultrasonic atomization behavior and preparation of low-melting-point alloy powders.. Viscous damping and acoustic radiation pressure challenge the ultrasonic atomization of high-viscosity and high-surface-tension fluids. To address this issue and reveal the underlying mechanisms, a rotational ultrasonic atomization platform was developed. The effects of ultrasonic power, liquid viscosity, horn geometry, rotation speed, and initial momentum on atomization behavior were investigated using high-speed imaging. For low-viscosity liquids, increasing ultrasonic power elevated the Weber number, widened the spray angle from 63 degrees to 142 degrees, and shortened the atomization incub…

Evidence: 42 • authority: 72

In continuum mechanics, stress is a physical quantity that describes forces present during deformation. For example, an object being pulled apart, such as a stretched elastic band, is subject to tensile stress and may undergo elongation. An object being pushed together, such as a crumpled sponge, is subject to compressive stress and may undergo shortening. The greater the force and the smaller the cross-sectional area of the body on which it acts, the greater the stress. Stress has dimension of force per area, with SI units of newtons per square meter (N/m2) or pascal (Pa). Stress expresses the internal forces that neighbouring particles of a continuous material exert on each other, while s…

Evidence: 36 • authority: 80

Evidence: 36 • authority: 92

Effect of rolling surface texture on bearing friction pairs lubrication.. Inspired by the friction-reducing structure of pangolin scales, biomimetic conical textures were designed on bearing roller-raceway surfaces to improve tribological performance and service life. Computational fluid dynamics (CFD) based on hydrodynamic lubrication and cavitation theory was used to simulate the effects of cavitation, inflow direction, and texture parameters (depth, area ratio, and angle) on oil film load capacity. Femtosecond laser fabrication and oil-lubricated friction tests were conducted for validation. The results demonstrate that the load-carrying capacity of the oil film is significantly improved…

Evidence: 36 • authority: 92

Engineering principles in plant metabolism: integrating control, mechanics, and transport under dynamic environments.. Plant responses to dynamic environmental conditions remain challenging to describe within a unified mechanistic framework. This is largely because metabolism operates under simultaneous and interacting regulatory, mechanical, and transport constraints. Here, we synthesize three engineering perspectives as complementary frameworks to quantify these constraints on plant metabolism: (i) control engineering, for dynamic regulation of the biochemical pathways; (ii) structural and mechanical engineering, to quantify load-bearing constraints and geometry-dependent scaling relation…

Evidence: 36 • authority: 72

In fluid dynamics, the Reynolds number (symbol Re) is a characteristic number that helps predict fluid flow patterns in different situations by measuring the ratio between inertial and viscous forces. At low Reynolds numbers, flows tend to be dominated by laminar (sheet-like) flow, while at high Reynolds numbers, flows tend to be turbulent. The turbulence results from differences in the fluid's speed and direction, which may sometimes intersect or even move counter to the overall direction of the flow (eddy currents). These eddy currents begin to churn the flow, using up energy in the process, which for liquids increases the chances of cavitation. The Reynolds number has wide applications,…