  We present nsCouette, a highly scalable software tool to solve the
Navier-Stokes equations for incompressible fluid flow between differentially
heated and independently rotating, concentric cylinders. It is based on a
pseudospectral spatial discretization and dynamic time-stepping. It is
implemented in modern Fortran with a hybrid MPI-OpenMP parallelization scheme
and thus designed to compute turbulent flows at high Reynolds and Rayleigh
numbers. An additional GPU implementation (C-CUDA) for intermediate problem
sizes and a basic version for turbulent pipe flow (nsPipe) are also provided.
