Round, vertical hole through a sea-cliff. When water and air are forced into the hole through wave action, jets, fountains and sprays of water can occur.
The holes in the head plate or blow plate of a core-blowing machine through which sand is blown from the reservoir into the core box. The irregular shaped cavities with smooth walls produced in a casting when gas is entrapped during mold filling. The gas sources may be air, binder decomposition products or gases dissolved in the molten steel. See Blow.