Exa Corporation was a developer and distributor of computer-aided engineering (CAE) software. Its main product was PowerFLOW, a lattice-boltzmann derived implementation of computational fluid dynamics (CFD), which can very accurately simulate internal and external flows in low-Mach regimes. PowerFLOW is used extensively in the international automotive and transportation industries. On November 17, 2017, Dassault Systèmes completed acquisition of Exa Corporation. Exa became part of Dassault's SIMULIA brand.