Autorotation & the flight of debris, London

16 March, 2016 | 18:00 - 20:00

Minor damage from flying debris on the upper parts of buildings.
Minor damage from flying debris on the upper parts of buildings.

About this event

The Flight of Windborne Debris: Flying debris striking buildings is the principal cause of building envelope failure and is responsible for up to a quarter of all fatalities during storms.

This lecture will introduce various scenarios where debris damage has been important and will also classify the types of debris. For example, the "Debris Damage Chain" will be discussed in the context of urban storm damage. Finally, the results from a number of experimental and numerical modelling studies (using CFD) will be presented that aim to characterise the flight of sheet debris. Sheet debris describes pretty well cladding, large roof tiles and road signs that find themselves airborne.

Tumbling and Autorotation: Tumbling has many similarities to autorotation, and it is common to apply data from fixed-axis wind tunnel testing to free-flight modelling. This lecture will briefly review many instances of autorotation / tumbling which may not be familiar to the wind engineer, before looking at the similarities and differences between fixed-axis and free-flight motions.

Aspects considered will include effects of geometry, transitions between motion regimes, scaling from model testing and motion modelling. The implications for the prediction of tumbling debris trajectories will be discussed.

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Dr David Hargreaves

University of Nottingham

David graduated in physics at Bristol University in 1989 and then worked at British Nuclear Fuels plc developing software to model pollution in groundwater. He returned to academia in 1994 and gained his PhD in atmospheric dispersion modelling from Nottingham University in 1997, supervised by Prof Chris Baker.

After a post-doctoral position, he was appointed as lecturer in 1999 in the School of Chemical Engineering at Nottingham. He then left in 2001 and worked for Fluent in Sheffield as a Principal Engineer, working on software support, development and consultancy. He returned to Nottingham in 2004, again as a lecturer but this time in Civil Engineering, working on the application of Computational Fluid Dynamics to a whole range of environmental problems, chief among those being pollution dispersion and the effects of wind on dynamic structures. David is a Chartered Engineer through the Institute of Physics.

Dr Doug Greenwell

Dr Doug Greenwell (Aircraft Research Association) joined the Aircraft Research Association in 2014 as Principal Aerodynamicist, with responsibility for the development and industrialisation of aerodynamic capabilities. He has over 25 years' experience in experimental aerodynamics, flight dynamics and aircraft performance, acquired whilst working in industry, academia and government research organisations.

Doug gained his PhD in delta wing aerodynamics at the University of Bath in 1993, and has maintained an interest in unsteady separated bluff-body flows ever since. He was first exposed to helicopter sling load issues when working at DERA (now QinetiQ) in the 1990s, and has returned to the field on a number occasions as an academic (Bristol University and City University) and an industrial aerodynamicist.