The frozen-momentum point-block preconditioner for the Newton–Krylov momentum solver (preconditioner.model: frozen_momentum_jacobian) is now supported. Every one of 13,500 steps converged and committed across a three-grid laminar study of the Humphrey, Taylor & Whitelaw (1977) square-duct bend at Re = 790, with divergence below 5e-10. The claim is correct execution, not speed: it was not compared against running without a preconditioner, and it is untested on wall-resolved, high-Reynolds-number grids. The campaign's comparison with the 1977 measurements and its grid-convergence analysis are recorded in the Newton–Krylov page.