  In this paper, we describe an upgrade of the Alya code with up-to-date
parallel linear solvers capable of achieving reliability, efficiency and
scalability in the computation of the pressure field at each time step of the
numerical procedure for solving a Large Eddy Simulation formulation of the
incompressible Navier-Stokes equations. We developed a software module in
Alya's kernel to interface the libraries included in the current version of
PSCToolkit, a framework for the iterative solution of sparse linear systems on
parallel distributed-memory computers by Krylov methods coupled to Algebraic
MultiGrid preconditioners. The Toolkit has undergone various extensions within
the EoCoE-II project with the primary goal of facing the exascale challenge.
Results on a realistic benchmark for airflow simulations in wind farm
applications show that the PSCToolkit solvers significantly outperform the
original versions of the Conjugate Gradient method available in the Alya's
kernel in terms of scalability and parallel efficiency and represent a very
promising software layer to move the Alya code towards exascale.
