Editing Similitude (section)

{{Short description|Concept applicable to the testing of engineering models}}
{{Other uses|Similitude (disambiguation)}}
{{More citations needed|date=May 2009}}
[[File:Wind tunnel x-43.jpg|thumb|right|280px|A full scale [[NASA X-43|X-43]] [[wind tunnel]] test. The test is designed to have '''dynamic similitude''' with the real application to ensure valid results.]]

'''Similitude''' is a concept applicable to the testing of [[engineering]] [[physical model|models]]. A model is said to have ''similitude'' with the real application if the two share [[geometric]] similarity, [[kinematics|kinematic]] similarity and [[Dynamics (mechanics)|dynamic]] similarity. ''Similarity'' and ''similitude'' are interchangeable in this context.
The term '''''dynamic similitude''''' is often used as a catch-all because it implies that geometric and kinematic similitude have already been met.

Similitude's main application is in [[hydraulic]] and [[aerospace engineering]] to test [[fluid flow]] conditions with [[Scale (ratio)|scaled]] models. It is also the primary theory behind many textbook [[formula]]s in [[fluid mechanics]].

The concept of similitude is strongly tied to [[dimensional analysis]].