[[wiki-architecture]] · [[Building Materials]] · [[ARCHITECTURE]] · [[000]] # D'Alembert–Euler condition In mathematics and physics, especially the study of mechanics and fluid dynamics, the d'Alembert-Euler condition is a requirement that the streaklines of a flow are irrotational. Let x = x(X,t) be the coordinates of the point x into which X is carried at time t by a (fluid) flow. Let x ¨ = D 2 x D t {\displaystyle {\ddot {\mathbf {x} }}={\frac {D^{2}\mathbf {x} }{Dt}}} be the second material derivative of x. Then the d'Alembert-Euler condition is: c u r l x = 0 . {\displaystyle \mathrm {curl} \ \mathbf {x} =\mathbf {0} .\,} The d'Alembert-Euler condition is named for Jean le Rond d'Alembert and Leonhard Euler who independently first described its use in the mid-18th century. It is not to be confused with the Cauchy–Riemann conditions. == References == - [[Professional Practice/Codes & Standards/National Building Code of India/Part 08 - Building Services/Section 3 - Air Conditioning]] - [[Urban and Planning/Urban Design]] - [[Professional Practice/Codes & Standards/National Building Code of India/Part 01 - Definitions]] - [[Interior Architecture]] - [[Environmental Design/Life Cycle Assessment]] - [[Professional Practice/Codes & Standards/National Building Code of India/Part 07 - Construction Management]] - [[Environmental Design/Building Climatology]] - [[Wiki-Architecture/Elements and Typologies]] - [[Urban and Planning/Urban Regeneration]] - [[History and Theory/World History/Contemporary Architecture]]