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Buoyancy force is the defined as the force exerted on the body or an object when inserted in a fluid. Buoyancy force is based on the basic principle of pressure variation with depth, since pressure increases with depth. Hence buoyancy force arises as pressure on the bottom surface of the immersed object is greater than that at the top.
Submerged specific gravity is a dimensionless measure of an object's buoyancy when immersed in a fluid.It can be expressed in terms of the equation = where stands for "submerged specific gravity", is the density of the object, and is the density of the fluid.
Buoyancy also applies to fluid mixtures, and is the most common driving force of convection currents. In these cases, the mathematical modelling is altered to apply to continua, but the principles remain the same. Examples of buoyancy driven flows include the spontaneous separation of air and water or oil and water.
(This formula is used for example in describing the measuring principle of a dasymeter and of hydrostatic weighing.) Example: If you drop wood into water, buoyancy will keep it afloat. Example: A helium balloon in a moving car. When increasing speed or driving in a curve, the air moves in the opposite direction to the car's acceleration.
In fluid mechanics, the Rayleigh number (Ra, after Lord Rayleigh [1]) for a fluid is a dimensionless number associated with buoyancy-driven flow, also known as free (or natural) convection. [2] [3] [4] It characterises the fluid's flow regime: [5] a value in a certain lower range denotes laminar flow; a value in a higher range, turbulent flow.
[2]: 128–129 The Boussinesq approximation states that the density variation is only important in the buoyancy term. If F = ρ g {\displaystyle F=\rho \mathbf {g} } is the gravitational body force, the resulting conservation equation is [ 2 ] : 129
Neutral buoyancy occurs when an object's average density is equal to the density of the fluid in which it is immersed, resulting in the buoyant force balancing the force of gravity that would otherwise cause the object to sink (if the body's density is greater than the density of the fluid in which it is immersed) or rise (if it is less). An ...
The middle segment has buoyant material attached along its entire length, so that the ensemble of the steel pipe and the buoyancy is positively buoyant. Accordingly, the curvature of the buoyant segment 'bulges' upwards (inverted catenary), and its shape can also be well approximated with the same stiffened or ideal catenary equations.