Dr Sam Grimshaw

Girton College MHI Turbomachinery Senior Research Fellow


Sam is the Mitsubishi Heavy Industries Senior Research Fellow in Turbomachinery. His research at the Whittle Laboratory helps to develop new technologies for the energy and aerospace sectors.

Sam obtained his PhD from the Whittle Laboratory in 2013 for his work on axial compressor bleed and since then has continued to work with Mitsubishi Heavy Industries (MHI) on off-design compressor aerodynamics which aims to improve the efficiency and handling characteristics of industrial gas turbine compressors. He is part of the team which developed the successful proposal for the New Whittle Laboratory and is now working to help deliver the project’s revolutionary new test facilities.   

As well as working with MHI, Sam has set up the Whittle Lab’s collaboration with Reaction Engines. This has resulted in Masters student research projects investigating counter rotating turbines, super-aggressive compressor S-ducts and Helium turbine design, all with the aim of improving efficiency and reducing the weight of Reaction Engines’ SABRE engine.

Sam is involved in the Whittle Laboratory’s research into the emerging field of electric aircraft design and is running two student projects which are investigating the performance of ducted fan propulsors. These projects combine computational simulations, a static test rig and a flying quadcopter and aim to improve the performance of propulsion for e-VTOL (electric vertical take-off and landing) aircraft.

Underpinning much of his research, Sam is experienced in both time-averaged and unsteady measurement techniques and has recently developed a novel method to improve the accuracy of pneumatic probe measurements in non-uniform flow fields. He is currently working on high-fidelity unsteady measurements of stall inception in axial compressors.

Sam’s teaching responsibilities include Part I maths and Part II compressible flow supervisions for Girton College as well as supervising 4th Year Masters students. He leads the Whittle Laboratory project for the Clifton Scientific Trust which provides 12 English and Japanese school children with the opportunity to experience a week-long research project in a university laboratory setting.

Away from work Sam enjoys playing hockey and is involved in coaching and administration for both Cambridge University and Cambridge City Hockey Clubs. Sam’s love of sport, and cricket in particular, has spilled over into his research as he is currently supervising a PhD project investigating the aerodynamics of cricket ball swing.  


  • 2014 ASME Turbomachinery Committee Best Paper Award for “Bleed Induced Distortion in Axial Compressors”.
  • 2016 ASME Education Committee Best Paper Award for “A Computational and Experimental Compressor Design Project for Japanese and British High-School Students”.
  • 2017 ASME Turbomachinery Committee Best Paper Award for “The Role of Tip Leakage Flow in Spike-type Rotating Stall Inception”.

Research topics

Publications & updates

Loss in Axial Compressor Bleed Systems

A new method for characterising bleed system loss is introduced, using research compressor test results as a demonstration case. A loss coefficient is defined for a control volume including only flow passing through the bleed system. The coefficient takes a measured value of 95% bleed system inlet dynamic head, and is shown to be a weak function of compressor operating point and bleed rate, varying by +/-2.2% over all tested conditions. This loss coefficient is the correct non-dimensional metric for quantifying and comparing bleed system performance.


S.D. Grimshaw, J. Brind, G. Pullan, R. Seki


Proceedings of ASME Turbo Expo 2019

A Pneumatic Probe for Measuring Spatial Derivatives of Stagnation Pressure

This paper introduces a pneumatic 9-hole probe which can measure flow angles, stagnation and static pressures, and spatial derivatives of stagnation pressure. It does this through direct measurement at a single location, rather than empirical corrections using measurements at multiple points. The new design resembles a 5-hole probe with 4 additional holes positioned around the side of the probe head. This arrangement enables the probe to distinguish between flows with stagnation pressure gradient and flows at an angle. Mapping between the inputs, the probe hole pressures, and outputs, the calibration reference measurements, is achieved with a trained neural network which takes the place of a conventional calibration map.


C.J. Clark, S.D. Grimshaw


Proceedings of ASME Turbo Expo 2019

Bleed Induced Distortion in Axial Compressors


S. D. Grimshaw, G. Pullan, T. Walker


Journal of Turbomachinery (2015) Vol. 137, Issue 9, Article 101009



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Career opportunities

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