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The equation to calculate the pressure inside a fluid in equilibrium is: f + div σ = 0 {\displaystyle \mathbf {f} +\operatorname {div} \,\sigma =0} where f is the force density exerted by some outer field on the fluid, and σ is the Cauchy stress tensor .
Hydrostatic weighing, also referred to as underwater weighing, hydrostatic body composition analysis and hydrodensitometry, is a technique for measuring the density of a living person's body. It is a direct application of Archimedes' principle, that an object displaces its own volume of water.
The Archimedes number is applied often in the engineering of packed beds, which are very common in the chemical processing industry. [3] A packed bed reactor, which is similar to the ideal plug flow reactor model, involves packing a tubular reactor with a solid catalyst, then passing incompressible or compressible fluids through the solid bed. [3]
An object immersed in a liquid displaces an amount of fluid equal to the object's volume. Thus, buoyancy is expressed through Archimedes' principle, which states that the weight of the object is reduced by its volume multiplied by the density of the fluid. If the weight of the object is less than this displaced quantity, the object floats; if ...
Dimensionless numbers (or characteristic numbers) have an important role in analyzing the behavior of fluids and their flow as well as in other transport phenomena. [1] They include the Reynolds and the Mach numbers, which describe as ratios the relative magnitude of fluid and physical system characteristics, such as density, viscosity, speed of sound, and flow speed.
Archimedes was asked to determine whether some silver had been substituted by the goldsmith without damaging the crown, so he could not melt it down into a regularly shaped body in order to calculate its density. [36] In this account, Archimedes noticed while taking a bath that the level of the water in the tub rose as he got in, and realized ...
To calculate the weight of the displaced water, it is necessary to know its density. Seawater (1,025 kg/m 3) is more dense than fresh water (1,000 kg/m 3); [5] so a ship will ride higher in salt water than in fresh. The density of water also varies with temperature.
The density is determined by weighing the sample in air and then in a liquid of known density. Application of Archimedes’ principle leads to the following expression for the measured density of the sample in terms of measured weight, where subscripts “a” and “L” refer to water and liquid, respectively: [5]