specific yield การใช้

• Often the porosity or effective porosity is used as an upper bound to the specific yield.
• Specific yield can be close to effective porosity, but there are several subtle things which make this value more complicated than it seems.
• Also, the value of specific yield may not be fully realized for a very long time, due to complications caused by unsaturated flow.
• The value for specific yield is less than the value for porosity because some water will remain in the medium even after drainage due to intermolecular forces.
• By incorporating the correct definitions for saturated thickness, specific storage, and specific yield, we can transform this into two unique governing equations for confined and unconfined conditions:
• Specific yield ( " S y " ) is also a ratio between 0 and 1 ( " S y " d " porosity ) and indicates the amount of water released due to drainage from lowering the water table in an unconfined aquifer.
• Aquifers are broadly classified as being either confined or unconfined ( water table aquifers ), and either saturated or unsaturated; the type of aquifer affects what properties control the flow of water in that medium ( e . g ., the release of water from storage for confined aquifers is related to the storativity, while it is related to the specific yield for unconfined aquifers ).