– Physics:
– Fluids display properties like lack of resistance to permanent deformation and the ability to flow.
– Solids respond to shear with a restoring force, while fluids respond with restoring forces only to normal stresses.
– Both solids and liquids have free surfaces that require energy to form.
– Gases, unlike solids and liquids, freely diffuse due to the lack of free surfaces.
– In response to surface tension, liquids tend to form rounded droplets.
– Modelling:
– Shear stress in solids is a function of strain, while in fluids, it is a function of strain rate.
– The behavior of fluids can be described by the Navier–Stokes equations, based on principles like conservation of mass and energy.
– Fluid mechanics is the study of fluids, divided into fluid dynamics and fluid statics based on motion.
– Pascals law describes the role of pressure in characterizing a fluid’s state.
– The study of fluids is crucial in understanding various phenomena in physics and engineering.
– Classification of fluids:
– Fluids can be categorized as Newtonian or Non-Newtonian based on the relationship between stress and rate of strain.
– Compressible fluids experience volume reduction or density change under pressure, while incompressible fluids like water maintain constant volume.
– Perfect fluids are theoretical constructs that ignore viscosity and compressibility effects.
– Understanding the classification of fluids is essential in fields like aerodynamics and materials science.
– The behavior of fluids under different conditions impacts their applications in industries such as aerospace and automotive.
– See also:
– Matter, liquid, gas, and supercritical fluids are related concepts to fluid dynamics.
– Understanding the properties of different states of matter is fundamental in various scientific disciplines.
– Fluid mechanics plays a crucial role in understanding the behavior of fluids in different environments.
– Exploring the relationships between different states of matter helps in advancing technologies and scientific knowledge.
– Studying fluids and their properties contributes to advancements in fields like medicine, engineering, and environmental science.
– References:
– Fluid mechanics is a complex field that requires a deep understanding of physics and mathematics.
– Various sources provide valuable information on the properties and behavior of fluids.
– The study of fluids has practical applications in industries such as manufacturing and energy production.
– Research in fluid dynamics continues to drive innovations in technology and scientific research.
– Accessing reliable references is essential for gaining a comprehensive understanding of fluid dynamics and its applications.
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In physics, a fluid is a liquid, gas, or other material that may continuously move and deform (flow) under an applied shear stress, or external force. They have zero shear modulus, or, in simpler terms, are substances which cannot resist any shear force applied to them.
Although the term fluid generally includes both the liquid and gas phases, its definition varies among branches of science. Definitions of solid vary as well, and depending on field, some substances can have both fluid and solid properties. Non-Newtonian fluids like Silly Putty appear to behave similar to a solid when a sudden force is applied. Substances with a very high viscosity such as pitch appear to behave like a solid (see pitch drop experiment) as well. In particle physics, the concept is extended to include fluidic matters other than liquids or gases. A fluid in medicine or biology refers to any liquid constituent of the body (body fluid), whereas "liquid" is not used in this sense. Sometimes liquids given for fluid replacement, either by drinking or by injection, are also called fluids (e.g. "drink plenty of fluids"). In hydraulics, fluid is a term which refers to liquids with certain properties, and is broader than (hydraulic) oils.
English
Etymology
From Middle English fluid, from Latin fluidus (“flowing; fluid”), from Latin fluō (“to flow”), from Proto-Indo-European *bʰleh₁- (“to swell; surge; overflow; run”).