Instability and sensitivity analysis of flows using OpenFOAM®

The present contributions deal with the development and implementation of the direct and adjoint incompressible Navier–Stokes equations in a matrix-free time-stepping context making use of the open-source OpenFOAM® (open source field operation and manipulation) C++ toolbox. It is shown that a few minor modifications in the source code can enable these multi-purpose computational fluid dynamics (CFD) solvers to carry out global instability analysis of three-dimensional flows of engineering interest, exploiting all additional capabilities of such codes. The strength of this methodology is demonstrated through the analysis of an interesting selection of open and wall-bounded flows.