Postdoctoral Research Associate in experimental fluid dynamics

European Geosciences Union (EGU); Wimereux; On-site; EUR 26,000 - 30,000; Full time

Job summary

ULCO invites applications for a post-doctoral position in experimental fluid dynamics to study copepod behavior in turbulence. The project combines ultrasonic Doppler measurements with the Agiturb system to quantify fluid and copepod velocities in a controlled tank.

The successful candidate will set up experiments, explore Reynolds-number effects on behavior, and work within the LOG Laboratory of Oceanology and Geosciences in Wimereux, France, starting Jan 2027.

Qualifications

• Holds a PhD in Physical Oceanography or Fluid Mechanics.

Responsibilities

• Set up the experiment using the Agiturb system and ultrasonic equipment.
• Investigate the effect of Reynolds number on copepod–fluid interactions.

Skills

Experimental fluid dynamics

Academic collaboration

Education

PhD

Tools

Ultrasonic Doppler sonar

Agiturb system

Job description

Some features of our web site require JavaScript to function properly. Please enable JavaScript in your browser.

Position

Postdoctoral Research Associate in experimental fluid dynamics

Employer

ULCO

Université du Littoral Côte d'Opale.

Homepage

https://www.univ-littoral.fr

Location

Wimereux, France

Sector

Academic

Relevant divisions

Nonlinear Processes in Geosciences (NP)

Ocean Sciences (OS)

Type

Contract

Level

Experienced

Salary

26000 - 30000 € / Year, €2,800 gross/month (net salary ~€2400/month).

Required education

PhD

Application deadline

18 October 2026

Posted

16 September 2026

Job Description

Post-doc position entitled “Experimental study of copepods in turbulence”

Introduction

Copepods are small crustaceans belonging to zooplankton, with a size comparable to the Kolmogorov scale (on the order of millimeters). They are capable of swimming and jumping. While the relationship between turbulence and copepods is critical, it remains poorly understood. It is unclear whether copepods are attracted to turbulence or avoid it, nor is there a defined turbulence threshold that might trigger a transition between attraction and avoidance behaviors [1]. Understanding this dynamic is essential for interpreting the collective behavior of copepods in relation to their environment, including turbulent forcing.

Although significant progress in numerical simulation has been enabled over the past 15 years by understanding the dominant role played by small-scale interactions between water turbulence and the dispersed particulate phase, the validity of these models and identified processes remains limited by our inability to provide high-resolution velocity field measurements of both the fluid and the particles (organic or inorganic). In this context, pulsed ultrasound techniques in the MHz range outperform particle image velocimetry techniques due to acoustic attenuation being much lower than that encountered with laser-based optical systems. Using these acoustic techniques, the amplitude and phase of the measured echoes make it possible to estimate concentration and multi-component velocities [2,3]. These systems thus appear particularly well-suited to studying turbulence-particle interactions in aquatic environments.

In this framework, the aim of the project is to characterize the interactions between copepod behavior and turbulence using ultrasonic techniques in a controlled environment. The expected results will provide quantitative insights into whether copepods are attracted to, flee from, or remain indifferent to localized turbulence.

Laboratory Experimentation

The study will be conducted using the Agiturb system, developed at LOG [4]. This system employs four counter-rotating agitators beneath a tank, generating a field which is approximately isotropic at the center, with turbulence levels controlled by the agitators’ rotation speed, with Taylor-based Reynolds numbers from 130 to 350.

An ultrasonic Doppler sonar, developed under the RUPTURE project (UBLab 3C – Ubertone®), will be utilized. Its multi-bistatic geometry (one emitter, 4 receivers) enables collocated 3C velocity field measurements and concentration along a vertical profile with high spatial (mm) and temporal (ms) resolutions. Its capability to work at multiple carrier frequencies (MHz) is key to resolve both the dispersed and carrier phases of the flow and investigate turbulence-particle interactions in turbulent flows.

As such, in the context of the present post-doctoral research, this system is necessary to provide simultaneous time-resolved measurements of the fluid velocity as well as the copepod velocity and biovolume. High-speed cameras will also be available to reconstruct copepod trajectories.

In the frame of the french ANR RUPTURE and CPER IDEAL, the postdoctoral researcher will be expected to:

• Setting up the experiment using this equipment.
• Investigating the effect of the Reynolds number on the differential behavior of living copepods relative to the fluid.
• Schmitt, F.G.. Turbulence et écologie marine, Ellipses, Paris, 2020, 246pp.
• Fromant et al. (2018), JGR Earth Surface 123(10) 2546. https://doi.org/10.1029/2017JF004560
• Fromant et al. (2024), J. Acoust. Soc. Am. 155(4) 2817. https://doi.org/10.1121/10.0025766
• Le Quiniou et aL; (2022), Eur. Phys. J. Plus 137, 250. https://doi.org/10.1140/epjp/s13360-022-02455-7

Practical Informations

• Funding: ANR RUPTURE (PI: Guillaume Fromant, ULCO, LISIC).
• Host Institution: Laboratory of Oceanology and Geosciences (LOG), Wimereux, France – http://log.cnrs.fr.
• Supervision: F.G. Schmitt (Ph. D., CNRS, LOG, France) & G. Fromant (Ph. D., ULCO, LISIC, France) – Contact: [e-mail], [e-mail]
• Duration: 12 months, starting January 2027.
• Salary: €2,800 gross/month (net salary ~€2400/month).

Eligibility Requirements

• Hold a PhD in Physical Oceanography or Fluid Mechanics.
• Prior experience in experimental work is not required but is a plus.