10 papers · 1 filter
Streak generation in viscosity-stratified wall-bounded flows
Anagha Madhusudanan, Simon J. Illingworth, Rama Govindarajan
Streamwise elongated flow structures, or streaks, dominate wall-bounded flows. We show that the renowned lift-up mechanism, that generates streaks, is significantly altered by visc…
Nonlinear estimation in turbulent channel flows
Jitong Ding, Simon J. Illingworth
We design a nonlinear estimator for channel flows at and . The nonlinear estimator uses a linear estimator structure based on the linearised Navier-Stokes equations…
Mode-to-mode nonlinear energy transfer in turbulent channel flows
Jitong Ding, Daniel Chung, Simon J. Illingworth
We investigate nonlinear energy transfer for channel flows at friction Reynolds numbers of and . The key feature of the analysis is that we introduce a new variable…
Energy transfer in turbulent channel flows and implications for resolvent modelling
Sean Symon, Simon J. Illingworth, Ivan Marusic
We analyse the inter-scale transfer of energy for two types of plane Poiseuille flow: the P4U exact coherent state of Park and Graham (2015) and turbulent flow in a minimal channel…
Energy transfer mechanisms and resolvent analysis in the cylinder wake
Bo Jin, Sean Symon, Simon J. Illingworth
Energy transfer mechanisms for vortex shedding behind a 2D cylinder at a Reynolds number of Re=100 are investigated. We first characterize the energy balances achieved by the true…
Feedback control of vortex shedding using a resolvent-based modelling approach
Bo Jin, Simon J. Illingworth, Richard D. Sandberg
An investigation of optimal feedback controllers' performance and robustness is carried out for vortex shedding behind a 2D cylinder at low Reynolds numbers. To facilitate controll…