Viper - spectral element flow solver
Viper is a high-order computational fluid dynamics solver written and maintained by Professor Gregory J Sheard. It uses a nodal spectral-element method for spatial discretisation, and time integration is via an operator-splitting scheme based on backwards-differentiation. Spectral elememt methods combine the ability to discretise complex geometries they share with finite element methods, with the superior spatial convergence characteristics of spectral methods. This is achieved through the use of high-order tensor-product Lagrange polynomial shape functions within each element interpolated over the Gauss-Lobatto-Legendre quadrature points, for efficient integration of the equations cast in weak form arising from application of the Galerkin method to elliptical operators.