Circulation theorem

{
  "id": "MLC-T-MET-004308",
  "term": "Circulation theorem",
  "field": "Meteorology and atmospheric science",
  "definition": "A principle in fluid dynamics, formulated by Vilhelm Bjerknes, that describes the time rate of change of circulation around a closed fluid loop. The theorem states that the change in circulation is proportional to the number of solenoids, or intersections of pressure and density surfaces, enclosed by the loop. In a barotropic fluid where density is only a function of pressure, the circulation around a fluid circuit is conserved.",
  "url": "https://mlchart.com/terminology/meteorology/circulation-theorem/"
}