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The mineral grains can be dissolved when there is fluid flow. The spaces originally occupied by the minerals will be spare as voids, increasing the porosity of rock. [2] The minerals that are usually dissolved are feldspar, calcite and quartz. [1] Grain dissolution pores results from this process can enhance porosity.
There are different flow patterns detected as a cavitation flow progresses: inception, developed flow, supercavitation, and choked flow. Inception is the first moment that the second phase (gas phase) appears in the system. This is the weakest cavitating flow captured in a system corresponding to the highest cavitation number. When the cavities ...
where is void ratio, is porosity, V V is the volume of void-space (air and water), V S is the volume of solids, and V T is the total or bulk volume of medium. [1] The significance of the porosity is that it gives the idea of water storage capacity of the aquifer. Qualitatively, porosity less than 5% is considered to be small, between 5 and 20% ...
Realistically, the effective stress is greater than the total stress, as the pore water pressure in these partially saturated soils is actually negative. This is primarily due to the surface tension of pore water in voids throughout the vadose zone causing a suction effect on surrounding particles, i.e. matric suction.
The concept of permeability is of importance in determining the flow characteristics of hydrocarbons in oil and gas reservoirs, [4] and of groundwater in aquifers. [5]For a rock to be considered as an exploitable hydrocarbon reservoir without stimulation, its permeability must be greater than approximately 100 md (depending on the nature of the hydrocarbon – gas reservoirs with lower ...
Porosity or void fraction is a measure of the void (i.e. "empty") spaces in a material, and is a fraction of the volume of voids over the total volume, between 0 and 1, or as a percentage between 0% and 100%. Strictly speaking, some tests measure the "accessible void", the total amount of void space accessible from the surface (cf. closed-cell ...
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For internal flows, flow separation produces an increase in the flow losses, and stall-type phenomena such as compressor surge, both undesirable phenomena. [8] Another effect of boundary layer separation is regular shedding vortices, known as a Kármán vortex street. Vortices shed from the bluff downstream surface of a structure at a frequency ...