Folyadéktípusok

Folyadéktípusok refers to the classification of fluids based on their behavior under stress. Understanding these different types is crucial in various fields, including fluid mechanics, engineering, and rheology. The primary distinction is between Newtonian and non-Newtonian fluids.

Newtonian fluids, such as water, air, and oil, exhibit a linear relationship between shear stress and shear rate. This means their viscosity remains constant regardless of the applied stress. In simpler terms, they flow consistently.

Non-Newtonian fluids, on the other hand, do not follow Newton's law of viscosity. Their viscosity changes depending on the applied shear stress or shear rate. This category is further divided into several subtypes. Shear-thinning fluids, like ketchup and paint, become less viscous when stirred or shaken. Shear-thickening fluids, such as cornstarch and water mixtures (oobleck), increase in viscosity under stress.

Thixotropic fluids are time-dependent non-Newtonian fluids that exhibit a decrease in viscosity over time when subjected to constant shear stress, and their viscosity recovers when the stress is removed. Examples include yogurt and some paints. Rheopectic fluids are the opposite, showing an increase in viscosity over time under constant shear stress.

Bingham plastics, like toothpaste, behave like a solid at low stress but flow like a fluid once a certain yield stress is exceeded. Pseudo-plastics are another term sometimes used for shear-thinning fluids. The study of these fluid behaviors is essential for designing pipelines, mixing equipment, and understanding natural phenomena.