Nicholas Cumpsty is a Professor Emeritus at Imperial College London. He conducted his postgraduate research at the University of Cambridge, where he was awarded a PhD for a dissertation entitled 'The Calculation of Three-Dimensional Turbulent Boundary Layers'. He has been a Professor of Aerothermal Technology at the University of Cambridge and a visiting professor at the Massachusetts Institute of Technology. Nick has also worked at Rolls Royce Ltd as a Senior Noise Engineer and, more recently, as a Chief Technologist. Andrew Heyes is Professor of Mechanical Engineering and Head of Department in Mechanical and Aerospace Engineering at the University of Strathclyde. He has previously held positions at the University of Leeds and Imperial College London, where he spent a number of years teaching engine design based on the second edition of Jet Propulsion. Before Imperial, he worked with Rolls-Royce and British Aerospace (Military Aircraft Division, Warton). He is a Chartered Engineer and Fellow of the Institution of Mechanical Engineers.