effusion vs flowrate

effusion

noun
  • The seeping of fluid into a body cavity; the fluid itself. 

  • Process of gases passing through a hole or holes considerably smaller than the mean free path of the gas molecules. 

  • An outpouring of speech or emotion. 

  • A liquid outpouring. 

flowrate

noun
  • The rate of flow, usually of a fluid, measured in either volume or mass per unit time. 

How often have the words effusion and flowrate occurred in a corpus of books? (source: Google Ngram Viewer )