TY  - JOUR
A1  - Böhnisch, Nils
A1  - Braun, Carsten
A1  - Muscarello, Vincenzo
A1  - Marzocca, Pier
T1  - About the wing and whirl flutter of a slender wing–propeller system
JF  - Journal of Aircraft
N2  - Next-generation aircraft designs often incorporate multiple large propellers attached along the wingspan (distributed electric propulsion), leading to highly flexible dynamic systems that can exhibit aeroelastic instabilities. This paper introduces a validated methodology to investigate the aeroelastic instabilities of wing–propeller systems and to understand the dynamic mechanism leading to wing and whirl flutter and transition from one to the other. Factors such as nacelle positions along the wing span and chord and its propulsion system mounting stiffness are considered. Additionally, preliminary design guidelines are proposed for flutter-free wing–propeller systems applicable to novel aircraft designs. The study demonstrates how the critical speed of the wing–propeller systems is influenced by the mounting stiffness and propeller position. Weak mounting stiffnesses result in whirl flutter, while hard mounting stiffnesses lead to wing flutter. For the latter, the position of the propeller along the wing span may change the wing mode shapes and thus the flutter mechanism. Propeller positions closer to the wing tip enhance stability, but pusher configurations are more critical due to the mass distribution behind the elastic axis.
Y1  - 2024
U6  - http://dx.doi.org/10.2514/1.C037542
SN  - 1533-3868
SP  - 1
EP  - 14
PB  - American Institute of Aeronautics and Astronautics
ER  - 
TY  - JOUR
A1  - Pieronek, Lukas
A1  - Kleefeld, Andreas
T1  - On trajectories of complex-valued interior transmission eigenvalues
JF  - Inverse problems and imaging : IPI
N2  - This paper investigates the interior transmission problem for homogeneous media via eigenvalue trajectories parameterized by the magnitude of the refractive index. In the case that the scatterer is the unit disk, we prove that there is a one-to-one correspondence between complex-valued interior transmission eigenvalue trajectories and Dirichlet eigenvalues of the Laplacian which turn out to be exactly the trajectorial limit points as the refractive index tends to infinity. For general simply-connected scatterers in two or three dimensions, a corresponding relation is still open, but further theoretical results and numerical studies indicate a similar connection.
KW  - Interior transmission problem
KW  - Eigenvalue trajectories
KW  - Complex-valued eigenvalues
Y1  - 2024
U6  - http://dx.doi.org/10.3934/ipi.2023041
SN  - 1930-8337 (Print)
SN  - 1930-8345 (Online)
VL  - 18
IS  - 2
SP  - 480
EP  - 516
PB  - AIMS
CY  - Springfield, Mo
ER  -