Getting in a jam: understanding clogging, flow, and stability in natural wood accumulations

Log jams — accumulations of floating wood in rivers — play a critical role in shaping fluvial landscapes, influencing flood dynamics, sediment transport, and aquatic ecosystems. Despite their ecological and hydraulic importance, we still lack a predictive, mechanistic understanding of how individual logs interact to form stable jams, how these structures resist or yield to flow, and how changes in geometry or hydrodynamic forcing drive transitions between clogging and release. This project will address these questions using particle-based computational simulations of log jam formation and deformation under flow. You will develop and apply numerical tools to represent logs as interacting elongated particles within a fluid environment, capturing contact, friction, buoyancy, and hydrodynamic drag. By systematically varying log aspect ratio, size distribution, and flow conditions, you will identify the micro-mechanical origins of jam stability and quantify the conditions under which logs transition between mobile, jammed, and partially clogging states. Through this work, you will develop expertise in large-scale particle-based simulation, computational fluid dynamics, and the physics of granular and particulate systems. You will learn to extract effective rheological and mechanical properties from microscale simulations, linking particle-scale processes to river-scale behaviour. The results will inform predictive models for log jam formation and stability, with implications for flood risk management, river restoration, and the design of nature-based engineering solutions. This PhD project will be supervised by Dr Chris Ness (School of Engineering, University of Edinburgh) and will involve collaboration with academics from partner institutions. Interested candidates are encouraged to contact the supervisor for more information (chris.ness@ed.ac.uk).

Website: https://christopherjness.github.io/ Contact: Dr Christopher John Ness(Chris.Ness@ed.ac.uk)

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

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

Applications are welcomed from self-funded students, or students who are applying for scholarships from the University of Edinburgh or elsewhere as well as self-funded students.

Funding Eligibility - Home applicants only (UK+EU settled/pre-settled)

Funding may be available for this project.

Further information and other funding options.