On the characteristic structure of the adjoint Euler equations and the analytic adjoint solution of supersonic inviscid flows

Fuente: arXiv
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Autori principali: Lozano, Carlos, Ponsin, Jorge
Natura: Preprint
Pubblicazione: 2025
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author Lozano, Carlos
Ponsin, Jorge
author_facet Lozano, Carlos
Ponsin, Jorge
contents 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 travelling 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.
format Preprint
id arxiv_https___arxiv_org_abs_2503_13007
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle On the characteristic structure of the adjoint Euler equations and the analytic adjoint solution of supersonic inviscid flows
Lozano, Carlos
Ponsin, Jorge
Fluid Dynamics
Numerical Analysis
Computational Physics
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 travelling 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.
title On the characteristic structure of the adjoint Euler equations and the analytic adjoint solution of supersonic inviscid flows
topic Fluid Dynamics
Numerical Analysis
Computational Physics
url https://arxiv.org/abs/2503.13007