61 citations · 198 across the 12 of their papers we have counts for
12 papers
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…
Resolvent-based approach for H2-optimal estimation and control: an application to the cylinder flow
Bo Jin, Simon J. Illingworth, Richard D. Sandberg
We consider estimation and control of the cylinder wake at low Reynolds numbers. A particular focus is on the development of efficient numerical algorithms to design optimal linear…
Optimal sensor and actuator placement for feedback control of vortex shedding
Bo Jin, Simon J. Illingworth, Richard D. Sandberg
We consider linear feedback control of the two-dimensional flow past a cylinder at low Reynolds numbers, with a particular focus on the optimal placement of a single sensor and a s…
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…
Linear control of coherent structures in wall-bounded turbulence at Re
Stephan F. Oehler, Simon J. Illingworth
We consider linear feedback flow control of the largest scales in an incompressible turbulent channel flow at a friction Reynolds number of Re = 2000. A linear model is formed…
Model-Based Estimation of Vortex Shedding in Unsteady Cylinder Wakes
Jiwen Gong, Jason P. Monty, Simon J. Illingworth
This paper considers single-sensor estimation of vortex shedding in cylinder wakes at in simulations and at in experiments. A model based on harmonic decompositi…
Streamwise-constant large-scale structures in Couette and Poiseuille flows
Simon J. Illingworth
The linear amplification mechanisms leading to streamwise-constant large-scale structures in laminar and turbulent channel flows are considered. A key feature of the analysis is th…
Coherent structures in the linearized impulse response of turbulent channel flow
Sabarish B. Vadarevu, Simon J. Illingworth, Ivan Marusic
We study the evolution of velocity fluctuations due to an isolated spatio-temporal impulse using the linearized Navier-Stokes equations. The impulse is introduced as an external bo…