PhD student in Experimental Fluid Mechanics and Sports Physics (M/F)

Job Description

Thesis Subject

The thesis project aims to understand the mechanisms of friction on ice and snow and to address practical questions raised by athletes from winter sports federations by combining the development of on-board sensors, field measurement campaigns, controlled laboratory experiments, and theoretical modelling of the physics of cold interfaces.
Gliding on snow and ice is a key factor in many winter sports (cross-country skiing, alpine skiing, snowboarding, figure skating, speed skating, ice hockey, curling, etc.), where the choice of equipment and any waxing products results in significant differences in performance due to variations in friction. For the 2030 Winter Olympic Games and with the ban on fluorinated products, which are harmful to the environment, the need for a robust scientific understanding has become strategic for the development of effective and environmentally friendly alternative solutions. Beyond the sporting arena alone, understanding the phenomenon of sliding on snow and ice has implications for numerous civilian and military applications: mobility in polar environments, the movement of vehicles or equipment on snow-covered or icy surfaces, and infrastructure safety. The mechanics of contact and friction on cold, deformable, meltable granular material constitute a fundamental problem in the physics of complex media, at the interface between fluid mechanics, solid mechanics, tribology and non-equilibrium thermodynamics. Despite its importance, the physical mechanisms underlying slippage are still not fully understood. In the case of snow, the difficulty stems from the material's heterogeneous, porous and evolving nature. But even for ice, the microscopic origin of sliding remains a matter of debate, in particular the exact role and nature of the layer of water that forms as a result of friction, as well as the contact angle of water on ice.
This project aims to overcome these obstacles by adopting an experimental approach, closely integrated with theoretical modelling, combining:
- the instrumentation of sports equipment and measurements under real-world conditions
We will develop instrumented skis and skates incorporating various sensors (thermocouples, strain gauges, accelerometers, load cells) to measure forces, temperature and local dynamics directly at the sliding interface.
- controlled field measurements, which eliminate human variability, to calibrate the on-board devices and provide a reliable quantification of the effectiveness of the sports equipment used. The proposed protocols include friction tests (deceleration and traction tests using portable devices), combined with a comprehensive environmental characterisation (air and ground temperature, humidity, snow type and condition) on natural ski runs and ice rinks.
- laboratory experiments, in which the physical parameters of snow or ice, and of materials, can be isolated and studied systematically. This work will draw on systems for the controlled production of snow and ice in cold rooms, capable of reproducing varying temperature and humidity conditions; tribometers (linear and rotary), enabling a parametric study of the influence of physical variables on friction; experimental methods for characterising snow (porosity, elasticity, crystal morphology, temperature, humidity) and the equipment used (thermal conductivity, roughness, wetting properties).
- The theoretical approach will be used to complement the experimental approach. It will enable friction measurements to be derived from field measurements under real-world conditions and from a model of skier/skater dynamics, and will link in situ measurements to fundamental experiments by extrapolating from the experimental conditions.
This integrated approach aims to rigorously quantify the mechanisms of friction on snow and ice, and to contribute to a unified understanding of the phenomenon of sliding. Ultimately, the project aims to establish a foundation of fundamental knowledge that can inform sporting performance, technological innovation and strategic applications in cold environments.

The ideal candidate will be experimentally minded (able to tinker with, design and improve experimental set-ups), independent, curious and creative, and possess a strong ability to solve technical problems and analyse data. A background in fluid mechanics is highly desirable.

Your Work Environment

The PhD research will take place at LadHyX, on the École Polytechnique campus. Experiments will be carried out in the laboratory's experimental rooms or cold chamber, and fieldwork will be organised. The work will be supervised by Caroline Cohen and Christophe Josserand, researchers at LadHyX, and by Romain Labbé, CEO of the company Phyling. The laboratory's working environment will enable the PhD student to interact with other PhD students specialising in fluid mechanics and sports physics, whilst collaborations with winter sports federations will provide opportunities to discuss matters with athletes and coaches who are specialists in their respective disciplines.

Compensation and benefits

Compensation

2300 € gross monthly

Annual leave and RTT

44 jours

Remote Working practice and compensation

Pratique et indemnisation du TT

Transport

Prise en charge à 75% du coût et forfait mobilité durable jusqu’à 300€

About the offer

About the CNRS

The CNRS is a major player in fundamental research on a global scale. The CNRS is the only French organization active in all scientific fields. Its unique position as a multi-specialist allows it to bring together different disciplines to address the most important challenges of the contemporary world, in connection with the actors of change.

CNRS

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