CENBOL
In astronomy, CENBOL (derived from "CENtrifugal pressure supported BOundary Layer) is a model developed by the astrophysicist Sandip Chakrabarti and collaborators to explain the region of an accretion flow around a black hole. Centrifugal force dominated boundary layer Because centrifugal force l2/r3 increases very rapidly compared to the gravitational force (which goes as 1/r2) as the distance r decreases, matter feels increasing centrifugal force as it approaches a black hole. Thus the matter initially slows down, typically through a shock transition, and then accelerates again to become a supersonic flow. The importance of CENBOL is that it behaves like a boundary layer of a black hole. This region is located between the shock and the innermost sonic point of an accretion flow. CENBOL becomes hot due to sudden reduction of radial kinetic energy and the flow is puffed up, since hot gas can fight against gravitational. In a certain sense it behaves like a thick accretion disk (ion pressure supported torus if the accretion rate is low; or radiation pressure supported torus, if the accretion rate is high), except that it also has radial velocity, which original models of thick disk did not have. Because it is hot, the electrons