Numerical simulation and physical modelling of turbulent fluid flow: aircraft drag reduction, rough-wall heat transfer, ship biofouling and sea waves

Project Leader: Daniel Chung
Staff: Nicholas Hutchins
Sponsors: Air Force Office of Scientific Research, Australian Research Council
Primary Contact: Daniel Chung (daniel.chung@unimelb.edu.au)
Keywords: computational fluid dynamics; drag reduction; fluid mechanics; turbulence; turbulent boundary layers
Disciplines: Infrastructure Engineering,Mechanical Engineering
Domains:

Seeking motivated individuals with a background in engineering, mathematics or physics to conduct numerical simulations and physical modelling in a collaborative environment on the projects below.

Aicraft drag reduction

Surface micro-grooves called riblets are designed for aircraft drag reduction, saving fuel and reducing emissions. Riblets are now installed on aircraft, but their tiny features are remain challenging to manufacture and maintain consistently. It turns out that the precise shape of the grooves can influence their drag-reduction performance. This project is about understanding the aerodynamics of off-design riblets to inform manufacturing and maintenance practices.

Rough-wall heat transfer

Cooling or heating of a surface next to turbulent flow impacts the efficiency of heat exchangers, gas turbines, high-speed generators and turbochargers, etc. However, our ability to model the relevant processes remains poor, relying on empiricism and without clear physical underpinnings. In this project, we aim to develop physics-accurate models of heat transfer for practical surface conditions, including roughness, localised heating (e.g. hot spots) and accounting for the working fluid (e.g. air, water).

Ship bio-fouling

In 2018, shipping (alone!) is responsible for 2.89% of global emissions (International Maritine Organization, 2020). The extra fuel cost due to bio-fouling amounts to hundreds of billions of US dollars annually. To manage this problem, ship operators clean the ship hulls, but hull cleaning is not free either. And so, to minimise costs, ship operators rely on mathematical models that map the state of the hull (think barnacles and turbeworms) to drag. However these models were not developed with data based on realistic bio-fouling, and so the aim of this project is to do generate realistic data and to develop physically sound models.

Sea waves

Sea waves are moving rough surfaces. Accurate wave forecasts benefit offshore operations, including fishing, shipping and wind energy. Current predictions of aerodynamic drag due to sea waves is poor, with scatter on the order of 100%. The bottleneck to progress has not been our ignorance of the problem but difficult or impossible access to systematic high-fidelity wind data, reporting not only drag, but also the detailed air flow. This project aims to generate these data and develop physical models to predict drag due to sea waves.

All these projects are on turbulent flow next to rough surfaces. See our review on the topic here: https://doi.org/10.1146/annurev-fluid-062520-115127

Further information: https://people.eng.unimelb.edu.au/chungd1/