  We propose an efficient, accurate and robust implicit solver for the
incompressible Navier-Stokes equations, based on a DG spatial discretization
and on the TR-BDF2 method for time discretization. The effectiveness of the
method is demonstrated in a number of classical benchmarks, which highlight its
superior efficiency with respect to other widely used implicit approaches. The
parallel implementation of the proposed method in the framework of the deal.II
software package allows for accurate and efficient adaptive simulations in
complex geometries, which makes the proposed solver attractive for large scale
industrial applications.
