Perturbation dynamics of turbulence
File(s)
Author(s)
Chua Khoo, Wee Zhao
Type
Thesis or dissertation
Abstract
Turbulence encountered in engineering applications is commonly found with various forms of external disturbances and perturbations that affect the dynamics and statistics of turbulence. Their understanding provides valuable physical insights into controlling turbulence in a robust way. This thesis investigates the Navier-Stokes equations via a statistical state dynamics framework. Via the statistical state dynamics framework, the chaotic aspects of turbulence can be regularised, leading to a more quantitative behaviour for understanding turbulence. Central to this is the closure problem that arises when an averaging procedure is applied to the Navier-Stokes equations which is non-linear in nature. Although initially, the aim was to quantify the aspects of the Reynolds stress terms in terms of a linear operator, the methodology is deemed to be too computationally expensive. Following on, a transient growth analysis is done on an ensemble of realisation of the Navier-Stokes equations, effectively putting it in contrast with a linearised Navier-Stokes equations operator augmented with the Cess eddy viscosity model.
Version
Open Access
Date Issued
2026-01-31
Date Awarded
2026-08-01
Copyright Statement
Attribution-NonCommercial 4.0 International Licence (CC BY-NC)
License URL
Advisor
Hwang, Yongyun
Publisher Department
Department of Aeronautics
Publisher Institution
Imperial College London
Qualification Level
Doctoral
Qualification Name
Master of Philosophy (MPhil)