Editing Venturi effect (section)

===Venturi tubes===
The simplest apparatus is a tubular setup known as a Venturi tube or simply a Venturi (plural: "Venturis" or occasionally "Venturies").  Fluid flows through a length of pipe of varying diameter.  To avoid undue [[aerodynamic drag]], a Venturi tube typically has an entry cone of 30 degrees and an exit cone of 5 degrees.<ref>{{cite book|last1=Nasr|first1=G. G.|last2=Connor|first2=N. E.|title=Natural Gas Engineering and Safety Challenges: Downstream Process, Analysis, Utilization and Safety|date=2014|publisher=Springer|isbn=9783319089485|page=183|chapter-url=https://books.google.com/books?id=C-01BAAAQBAJ&pg=PA183|language=en|chapter=5.3 Gas Flow Measurement}}</ref>

Venturi tubes are often used in processes where permanent pressure loss is not tolerable and where maximum accuracy is needed in case of highly viscous liquids.{{citation needed|date=April 2016}}