Examinando por Autor "Lozano, Carlos"

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Analytic adjoint solution for incompressible potential flows
(AIP Publishing, 2025-06-10) Lozano, Carlos; Ponsin, J.; Ponsin Roca, Jorge; Instituto Nacional de Técnica Aeroespacial (INTA)
We obtain the analytic adjoint solution for two-dimensional incompressible potential flow for a cost function measuring aerodynamic force using the connection of the adjoint approach to Green's functions and also by establishing and exploiting its relation to the adjoint incompressible Euler equations. By comparison with the analytic solution, it is shown that the naïve approach based on solving Laplace's equation for the adjoint variables can be ill-defined. The analysis of the boundary behavior of the analytic solution is used to discuss the proper formulation of the adjoint problem as well as the mechanism for incorporating the Kutta condition in the adjoint formulation.
Acceso Abierto
On the Characteristic Structure of the Adjoint Euler Equations and the Analytic Adjoint Solution of Supersonic Inviscid Flows
(Multidisciplinary Digital Publishing Institute (MDPI), 2025-05-30) Lozano, Carlos; Ponsin, J.; Ponsin Roca, Jorge; Instituto Nacional de Técnica Aeroespacial (INTA)
The characteristic structure of the two-dimensional adjoint Euler equations is examined. The behavior is similar to that of the original Euler equations, but with the information traveling in the opposite direction. The compatibility conditions obeyed by the adjoint variables along characteristic lines are derived. It is also shown that adjoint variables can have discontinuities across characteristics, and the corresponding jump conditions are obtained. It is shown how this information can be used to obtain exact predictions for the adjoint variables, particularly for supersonic flows. The approach is illustrated by the analysis of supersonic flow past a double-wedge airfoil, for which an analytic adjoint solution is obtained in the near-wall region. The solution is zero downstream of the airfoil and piecewise constant around it except across the expansion fan, where the adjoint variables change smoothly while remaining constant along each Mach wave within the fan.