Turbulence dynamics in spatially accelerating flows


Funded by EPSRC CASE Studentship, 2021-2023

PhD student: Matthew Falcone. Supervisor: Prof. Shuisheng He.

A radically new theory on transient turbulent channel flow has been proposed by our research group through a series of papers published between 2013 and 2020. In contrast to the conventional view, we have established that such a classical turbulent flow is actually characterised by a much simpler laminar boundary layer followed by transition. In addition, in another paper published in JFM in 2016, we have established a new interpretation of channel flow re-laminarisation, another important flow physics relevant to many engineering applications.

The current PhD project is aimed at extending the above two new channel-flow theories to external boundary layers to tackle the non-equilibrium turbulence phenomena. Such flow physics underpins flow control and drag reduction, an immensely important theme in the energy, transport and aerospace sectors. In particular, we aim to develop a step-change in the understanding of the spatially accelerating/decelerating flows under the influence of favourable/adverse pressure gradients. Initial results have indicated that phenomena observed in transient channel flow is present in spatially accelerating flows.

Streaks and vortexes in a spatial accelerating flow
High-/low-speed streaks and turbulence vortexes in a spatial accelerated channel flow

The study will make use of high performance computing (HPC) and an in-house CFD package CHAPSim based on an advanced methodology: direct numerical simulation (DNS). 

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