The Resistance of Ships with Multiscale Roughness

Understanding the hydrodynamics of marine coatings is critical to develop new products that minimise the friction resistance, the fuel consumption and the greenhouse emissions of marine transport. The challenge of modelling and predicting the friction resistance of ship hulls in real sailing conditions is due to the wide range of length-scales involved, from the micron-scale of the coating roughness to the metre-scale of the ship's boundary layer thickness (Raupach et al. Appl. Mech. Rev. 44 1991, Gad-el-Hak Appl. Mech. Rev. 49 1996). The width of this range of scales, and the fluid mechanics interaction between the scales, make the physics impossible to be replicated exactly in a laboratory setting (Gad-el-Hak Prog. Aerosp. Sci. 38 2002, Jimenez Annu. Rev. Fluid Mech. 36 2004).

A recent work funded by AkzoNobel's Marine, Protective & Yacht Coatings and undertaken at the University of Edinburgh showed the strong interaction between roughness features of different sizes. However, current practice is to consider one equivalent roughness height to model the effect of roughness on ship hulls (Yeginbayeva et al. Proc. Inst. Mech. Eng. Part M J. Eng. Marit. Environ. 233 2019). How to model the non-uniform distributions of roughness and combination of micro and macro roughnesses in numerical simulations of ship hulls is currently unknown. The recent review by Andersson et al. (Appl. Ocean Res. 99 2020) concludes that more research is needed to understand the combined effect on the full-scale friction resistance of the wide range roughness features on a ship hull. This project aims to address this key industry challenge with fundamental fluid mechanics research.

The aim of this project is to develop a methodology to accurately predict the friction resistance of ship hulls at full scale accounting for heterogenous fouling roughness, including hard fouling such as barnacles, and patchy slime with different thickness. New theoretical models of the interaction between different roughness features will be developed. These will be implemented into a Reynolds-averaged Navier-Stokes code (OpenFOAM) to compute the friction resistance of a full-scale hull for different surface conditions. 

The student will join the Vortex Interaction Laboratory ( within the Institute for Energy Systems of the School of Engineering, The University of Edinburgh. The project will be jointly supervised by Dr Ignazio Maria Viola (VOILAb) and Dr Haoliang Chen (AkzoNobel), and will include a three month secondment at AkzoNobel’s Marine, Protective & Yacht Coatings.

Further Information: 

For more information on the research environment, see the website of the research group of the main supervisor:

For more information on the industrial partner, see

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Closing Date: 

Monday, January 31, 2022

Principal Supervisor: 


Minimum entry qualification - an Honours degree at 2:1 or above (or International equivalent) in a relevant science or engineering discipline, possibly supported by an MSc Degree.

The applicant must demonstrate a strong interest in fluid mechanics. Expertise in computational fluid dynamics is not necessary but desirable.

Further information on English language requirements for EU/Overseas applicants.


EPSRC funded (see EPSRC student eligibility). Tuition fees + stipend available for applicants who qualify as Home applicants. (International applicants not eligible).

To qualify as a Home student, you must fulfil one of the following criteria:

  • You are a UK applicant.
  • You are an EU applicant with settled/pre-settled status who also has 3 years residency in the UK/EEA/Gibraltar/Switzerland immediately before the start of your programme.

Further information and other funding options.

Informal Enquiries: