5 papers
Linear Stability and Structural Sensitivity of a Swirling Jet in a Francis Turbine Draft Tube
Lester Corpin Toledo, Artur Gesla, Eunok Yim
Motivated by the need to better understand flow unsteadiness in hydraulic turbines, we perform a local linear stability and adjoint-based sensitivity analysis of the turbulent swir…
Vortex breakdown in a hydro turbine draft tube swirling jet
Artur Gesla, Eunok Yim
The swirling flow in a Francis type hydropower turbine is known to be susceptible to the formation of a large helical structure, commonly referred to as a vortex rope. This vortex…
From annular cavity to rotor-stator flow: nonlinear dynamics of axisymmetric rolls
Artur Gesla, Patrick Le Quéré, Yohann Duguet +1
Spatio-temporally complex flows are found at the onset of unsteadiness in (axisymmetric) rotor-stator turbulence in the shape of concentric rolls. The emergence of these rolls is r…
Computation and stability analysis of periodic orbits using finite differences, Fourier or Chebyshev spectral expansions in time
Artur Gesla, Yohann Duguet, Patrick Le Quéré +1
We analyse and compare several algorithms to compute numerically periodic solutions of high-dimensional dynamical systems and investigate their Floquet stability without building t…
On the origin of circular rolls in rotor-stator flow
Artur Gesla, Yohann Duguet, Patrick Le Quéré +1
Rotor-stator flows are known to exhibit instabilities in the form of circular and spiral rolls. While the spirals are known to emanate from a supercritical Hopf bifurcation, the or…