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The goal of this work is the development of a fully monolithic nonlinear Newton algorithm for the unstructured vertex-based finite volume algorithm presented in [Akkurt and Sahin, An efficient edge based data structure for the compressible RANS equations on hybrid unstructured meshes. International Journal for Numerical Methods in Fluids, 94:13-31, (2022)]. A special attention is paid for the highly accurate construction of the first- and second-order Jacobian matrices for the Navier–Stokes equations and the one-equation negative Spalart–Allmaras turbulence model. The inviscid flux Jacobian matrices are evaluated exactly using the source code transformations provided by the INRIA Tapenade library. The implementation of the nonlinear Newton method is carried out using the PETSc Scalable Nonlinear Equations Solvers (SNES) with a line search technique. The method can utilize both the Jacobian-free finite difference and direct approaches for the Jacobian vector product. The INRIA pyAMG anisotropic mesh adaptation library has been integrated in order to further improve its numerical accuracy at a lower computational cost. The algorithm has been applied to the two- and three-dimensional mesh convergence test cases from the 4th AIAA CFD High Lift Prediction Workshop in order to demonstrate its robustness in achieving machine precision for a realistic high-lift system. The highly accurate Jacobian evaluation process and high CFL numbers are found to be very critical for achieving machine precision. The mesh adaptation is also proven to be very robust in refining regions with high gradients, which is especially important for the simulations at high angles of attack, where it is rather difficult to determine refinement regions a priori. The anisotropic mesh adaptation studies are carried out for up to 92,993,470 vertices in three-dimensions, and the numerical results indicate very good agreement with the committee's experimental data. • A robust fully coupled (monolithic) nonlinear Newton method has been implemented. • Exact first- and second-order Jacobian evaluations are performemed efficiently. • The PTC algorithm is modified by consistently adding time devivation to both sides. • Anisotropic mesh adaptation has been integrated to enhance numerical accuracy. • Robustness in achieving machine precision is demonstrated for a high lift system. [ABSTRACT FROM AUTHOR]

Purpose – Air connectivity network is an important part of the overall connectivity network of any country. This becomes even more crucial for the interior regions, which have no access to sea routes and have inadequate road and rail connectivity. In India there is uniform distribution of airports throughout the country but only a few of them are currently used because of poor infrastructure availability at these airports. Any aircraft operating from these airports, having minimal infrastructure, need to have efficient high-lift systems for short takeoff and landing ability as one of the key requirements. The purpose of this paper is look at the performance of a new high-lift airfoil configuration for application to a general transport aircraft. Design/methodology/approach – The present study deals with two-dimensional analyses of a high-lift system for general transport aircraft. The JUMBO2D, a multi-block structured viscous code has been used to make preliminary analysis of the proposed high-lift system. The configuration consists of three elements, namely, the main airfoil with nose droop, a vane and a flap. Findings – In the present work the code has been revalidated by computing for NLF (1) 0416 airfoil (clean) and NACA 1410 airfoil with double-slotted flap. The computed results compare very well with the experimental data. The proposed high-lift configuration of general transport aircraft has then been analyzed in detail for both takeoff and landing conditions with and without nose droop. The effect of gap between main element and vane on the aerodynamic performance has also been investigated. Originality/value – This computational study looks at the performance of a new high-lift airfoil configuration for application to a general transport aircraft. [ABSTRACT FROM AUTHOR]