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The equation is derived for capillary flow in a cylindrical tube in the absence of a gravitational field, but is sufficiently accurate in many cases when the capillary force is still significantly greater than the gravitational force. In his paper from 1921 Washburn applies Poiseuille's Law for fluid motion in a circular tube.
Capillary pressure can also be utilized to block fluid flow in a microfluidic device. A schematic of fluid flowing through a microfluidic device by capillary action (refer to image of capillary rise of water for left and right contact angles in microfluidic channels) The capillary pressure in a microchannel can be described as:
The rate at which fluid is filtered across vascular endothelium (transendothelial filtration) is determined by the sum of two outward forces, capillary pressure and colloid osmotic pressure beneath the endothelial glycocalyx (), and two absorptive forces, plasma protein osmotic pressure and interstitial pressure (). The Starling equation is the ...
In physics, the Young–Laplace equation (/ l ə ˈ p l ɑː s /) is an algebraic equation that describes the capillary pressure difference sustained across the interface between two static fluids, such as water and air, due to the phenomenon of surface tension or wall tension, although use of the latter is only applicable if assuming that the wall is very thin.
Vasoconstriction affects flow rate and surface properties of the microvasculature by constricting the smooth muscle cells and decreasing the diameter of flow. The smooth muscle cells are able to constrict from both external and internal stimuli. This mechanism can be triggered by the ambient temperature or the autonomic nervous system. [7]
Pressure potential increases as water enters a cell. As water passes through the cell wall and cell membrane, it increases the total amount of water present inside the cell, which exerts an outward pressure that is opposed by the structural rigidity of the cell wall. By creating this pressure, the plant can maintain turgor, which allows the ...
For a water-filled glass tube in air at standard conditions for temperature and pressure, γ = 0.0728 N/m at 20 °C, ρ = 1000 kg/m 3, and g = 9.81 m/s 2. Because water spreads on clean glass, the effective equilibrium contact angle is approximately zero. [4] For these values, the height of the water column is
This means that the capillary pressure for a drainage process is different from the capillary pressure of an imbibition process with the same fluid phases. Hysteresis does not change the shape of the governing flow equation, but it increases (usually doubles) the number of constitutive equations for properties involved in the hysteresis.