Dr Ivor Day

Emeritus Fellow, Wolfson College


Dr Ivor Day (FREng) has worked for 11 years in Industry and a further 30 in Research. His research has covered the internal structure of stall cells, the application of active control to compressor surge, a study of stall inception mechanisms and a big investigation into the effects of rain ingestion on compressor performance.  He has helped develop a new low emissions combustion system for RR Industrial gas turbines and is now working on by-pass duct aerodynamics.  He is a Fellow of the Royal Academy of Engineering, has received the George Stephenson Prize, the Henry Royce Best Patent Award and, on six occasions, the ASME Gas Turbine Award.

Research topics

Over the years, a recurring theme in Dr Day’s research has been the stability of aero-engine compressors. In an engine, the low flow-rate end of the operating range is limited by stall or surge – both being aerodynamic disturbances which can cause damage to the fabric of the engine. A study of these instabilities is thus essential for the design of reliable compressors - especially as the instabilities themselves are not amenable to numerical modelling. Dr Day’s work has been mostly experimental concentrating on the disturbances themselves and then on finding ways of suppressing them. His studies have cover stall inception, stall recovery, stall warning, casing treatment, over-tip leakage, active control, passive control and blade tip clearance effects.

Other fields of interest include the study of rain ingestion by aero-engine compressors and the ensuing problem of rain ejection from the compressor core. Water spray cooling for hot-day operation of industrial power turbines has also been a field of interest. Furthermore, in relation to the use of gas turbines for power generation, Dr Day has worked on combustion instabilities caused by unsteady fuel injection. He holds a number of patents on this and other topics.

Publications & updates

Phase-averaged flow statistics in compressors using a rotated hot-wire technique


T. O. Jelly, I. J. Day and L. di Mare


Experiments in Fluids



Angular response of hot wire probes


L. di Mare, T. O. Jelly and I. J. Day


Measurement Science and Technology



Accounting for Eccentricity in Compressor Design


Young, A. M., Cao, T., Day, I. and Longley, J.


ASME Journal of Turbomachinery



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