Novel Methods for the Characterisation of Helicopter Aero-acoustics PhD

Updated: 4 days ago
Location: Cranfield, ENGLAND
Deadline: The position may have been removed or expired!

Cranfield University has been at the forefront of rotorcraft research for the last 13 years, having an established track record on rotorcraft modelling, performance, aero-mechanics, and aero-acoustics. This PhD studentship is within the Propulsion Engineering Centre at Cranfield University, in the field of helicopter aerodynamic and aero-acoustic modelling. The work will develop and deliver rapid analysis capability, which can assist with the prediction of noise characteristics throughout the vehicle design and service-life. This will be accomplished through the development of a novel tool for the rapid source noise prediction of integrated helicopter-engine systems.

The research will be sponsored by the Engineering and Physical Sciences Research Council (EPSRC) and the Defence and Science Laboratory (DSTL) in the UK. Read moreRead less

Current methods for the aero-acoustic characterisation of rotary-wing vehicles are based on the generation of acoustic hemi-spheres using either experimental means, or high-fidelity numerical methods. Both of these approaches are inherently unsuitable for preliminary design as the platform is not mature enough to populate high-fidelity methods or to develop physical models for testing. The analysis required to generate the acoustic hemispheres at vehicle level is further complicated by the any aerodynamic interactions between the rotors. With regards to helicopters, which this work focuses on, these aerodynamic interactions are due to the main rotor wake impinging on the tail rotor for certain operating conditions that depend on vehicle design characteristics. These interactions are usually neglected during aero-acoustic testing where the rotors are typically tested in isolation. This situation creates additional risk and inefficiency, as the aircraft developer must go through lengthy concept development phases which may, ultimately, prove to be incompatible with detectability requirements (defence and security) and/or certification (civil and military applications).

The proposed project aims to build a Reduced Order Model (ROM) capable of synthesising the noise hemispheres as functions of pertinent vehicle design parameters and operating conditions. A novel computational framework will be developed for helicopter noise hemisphere generation by integrating a series of validated Cranfield tools for rotor aero-mechanics and acoustics. A non-linear “free-wake” rotor model will be adapted to capture Blade Vortex Interaction (BVI) noise. This model will be extended to resolve the simultaneous evolution of the main and tail-rotor flow-fields, including the impact of the fuselage on the potential flow field. The acoustic model will be modified to be able to predict noise-hemispheres based on the combined free-wake flow solution of the main and tail rotor flows. This framework will be used to generate series of databases of noise hemispheres for a range of rotor architectures as functions of design parameters and operating conditions. Latin Hypercube Sampling (LHS) or Full Factorial (FF) sampling methods will be used for the Design of Experiments (DOE) to discretise the design space. State-of-the-art ROM approaches will be applied to analyse the noise data-bases, such as Proper Orthogonal Decomposition (POD) and dimensionality reduction (auto-encoders, non-linear Principal Component Analysis - PCA) to extract key aero-acoustic features. Surrogate modelling methods such as Gaussian Processes (Kriging) or Artificial Neural Networks (ANN), will be applied to derive analytical approximations of the scalar POD coefficients. The developed ROMs will be transferred to DSTL in the form of interpretable and generalizable aero-acoustic models using an agreed software format. This will be carried out through a series of dedicated student placements to facilitate the integration of the derived ROMs, as well as their application to a series of cases studies according to Dstl’s interest.

This PhD work will be sponsored by the Engineering and Physical Sciences Research Council (EPSRC) and the Defence and Science Laboratory (DSTL) in the UK. DSTL is an executive agency of the Ministry of Defence (MOD) providing world class expertise and delivering cutting-edge science and technology.

It is expected that the derived modelling approach will enhance DSTL’s predictive capability in terms of helicopter aero-acoustic characterisation during the stages of preliminary design and service life.

This PhD opportunity includes funding for the successful applicant to present their work in national and international conferences. The successful applicant will also be invited for at least one 3-month placement at DSTL to work alongside propulsion, aerodynamics and rotorcraft performance specialists at the Portsdown West site.

The successful applicant will gain an in-depth understanding of rotorcraft aerodynamics, aero-acoustics, and aero-mechanics. The student will also gain an understanding of contemporary methods for engineering data analytics, reduced-order modelling, Multi-Objective Optimisation (MOO), and modal decomposition.

Furthermore, the applicants will gain a unique and in-depth understanding of the field as well as a transferable skill-set, which will prepare them for a successful career in industry or academia. 

At a glance
  • Application deadline31 Jan 2023
  • Award type(s)PhD
  • Start dateAs soon as possible
  • Duration of award4 years (iCASE Award)
  • EligibilityUK
  • Reference numberSATM328

Entry requirements

Applicants must have a first-class or upper second-class degree in engineering or a related area. An aerospace background would be a distinct advantage, as would experience on aerodynamics and numerical modelling.


To be eligible for this funding, applicants must be a UK national only. Eligibility is also subject to person clearance by DSTL.

About the sponsor

Sponsored by the Engineering and Physical Sciences Research Council (EPSRC) and the Defence and Science Laboratory (DSTL), this studentship will provide a bursary of up to £15,609 (tax free) plus fees* for four years.

Cranfield Doctoral Network

Research students at Cranfield benefit from being part of a dynamic, focused and professional study environment and all become valued members of the Cranfield Doctoral Network.  This network brings together both research students and staff, providing a platform for our researchers to share ideas and collaborate in a multi-disciplinary environment. It aims to encourage an effective and vibrant research culture, founded upon the diversity of activities and knowledge. A tailored programme of seminars and events, alongside our Doctoral Researchers Core Development programme (transferable skills training), provide those studying a research degree with a wealth of social and networking opportunities.

How to apply

For further information please contact:

Name: Dr Ioannis Goulos

If you are eligible to apply for this studentship, please complete the online application form .

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