Fluid Mechanics Engineer

ENSTA, an institution of higher education and research under the authority of the Ministry of the Armed Forces, develops training, research, and innovation activities in the fields of defense and security, transportation, energy, maritime activities, digital technology, and health.

The school, present on two campuses, in Paris-Saclay and Brest, is a member of the Institut Polytechnique de Paris. Ranked in the Top 10 best engineering schools in France, its mission is:

• the training of civil and military engineering students, executives, and PhDs for the public and private sectors,

• high-level research and innovation in close collaboration with industry in major sovereignty sectors within 6 training and research units (UFR).

The holder of the position will be assigned to the Mechanics Training and Research Unit (UFR). The Mechanics UFR is responsible for training ENSTA's engineering students, Institut Polytechnique de Paris master's students, and conducting research training for French and foreign students at master's and doctoral levels. The Unit also develops research activities in the field of materials and structures mechanics, fluid mechanics, vibrations, and acoustics. These activities are carried out thanks to a significant high-level experimental facility in solid and fluid mechanics, for both teaching and research. On the Brest campus, the Mechanics UFR has about fifty teacher-researchers, fifty doctoral/post-doctoral students, and about ten technical staff (engineers, technicians). The research activities of the members of the Brest campus Mechanics UFR are conducted within the Dupuy de Lôme Research Institute (IRDL, CNRS UMR 6027, www.irdl.fr). The recruited person will work in close collaboration with the ENSTA teacher-researchers, in the thematic research pole "Structure Fluid Interaction (StIF)" of IRDL.

ENSTA is one of the partners in the SEARENITY project, selected under the "CORIMER Low-Carbon Ship" call for projects (funding from Ademe, France 2030). The project aims to develop an autonomous robot capable of continuously working on ship hulls to clean them and limit the growth of algae and shellfish, thereby reducing energy consumption and CO2 emissions.

ENSTA is involved in 2 aspects of the project, which present numerous and complex technical challenges:

• the magnetic attraction system: definition, simulation, and testing.

• the hydrodynamic aspect of the robot: modeling, numerical simulation, and wind tunnel testing

This job description concerns the hydrodynamic aspects.

Missions / Main Activities:

The recruited person will be responsible for the numerical evaluation of the forces experienced by the robot in various operating configurations, and will propose shape optimization strategies to improve performance. The developed models will also be validated through testing in the school's new wind tunnel. They will be required to produce technical reports and presentations, implement numerical simulation tools and testing, and work collaboratively with all SEARENITY project partners.

The detailed missions are as follows:

1. Experimental study in wind tunnel

Characterization and validation tests in the wind tunnel to validate numerical simulations for force estimation, as a function of various parameters (influence of flow speed, influence of angle of incidence). Setup of the test protocol, design of the support and 3D printing of the drone's reduced-scale model, calibration of sensors, operation of the wind tunnel.

2. Numerical study for submerged operation

Numerical determination of the average forces encountered by the drone in real conditions along the hull. Numerical simulations will be performed using a validated commercial calculation code, which is currently a reference for simulating high Reynolds number flows.

3. Dimensioning of impact forces in the splash zone

Numerical determination of impact forces when crossing the free surface, for different ship speeds and different drone angles of incidence. Numerical simulations will be performed using a calculation code developed by ENSTA, specifically dedicated to impact cases. Several water entry trajectories will be simulated to determine the maximum forces experienced by the structure.

4. Robot shape optimization

The nominal operation of the drone in submerged areas and the water entry phase lead to very different optimal geometric shapes. A literature review will be conducted to guide the search for the most suitable external shape, in terms of a compromise on acceptable forces. This literature review will possibly be supplemented by drag and impact calculations on academic geometries, to provide decision support for the drone designers.

Degree Level and Training

Master's degree (Bac +5) with initial experience – 2-3 years of experience would be a plus in the naval domain

Employment

Desired assignment duration: Fixed-term contract (CDD) of 12 months

Planned start date: 01/01/2027

Compensation:

• Contract employees: based on professional experience in equivalent level positions

Work location:

ENSTA Campus de Brest, 2 rue François Verny, 29200 Brest

"The site is accessible by car (parking for staff) or public transport. As the School is committed to CSR (Sustainable Development and Responsible Employer, and bike-friendly employer), it encourages sustainable mobility through financial aid (FMD) and infrastructure suitable for cyclists."

Full-time position (25 annual leave days, 23 RTT annual days)

Benefits:

• Transportation (employer's flat-rate contribution up to 75%)

• Sustainable mobility package (up to €300/year)

• Possibility of remote work (after trial period and with manager's agreement and submission of a request)

• Employer subsidy for the administrative restaurant and/or the establishment's cafeteria

• Social action committee, including events and activities offered to staff, gym on subscription,

• Health insurance (establishment's participation at 50%)

Workstation setup and inclusive recruitment:

All our positions are open to candidates with disabilities.

ENSTA is committed to recruitment that promotes equality, diversity, and inclusion. All applications without any distinction (age, disability, gender, nationality, religion, sexual orientation…) are welcome in our recruitment process.

About the School

ENSTA is a founding member of the Institut Polytechnique de Paris (IP Paris). Within the framework of IP Paris, the school participates in the activities of interdisciplinary centers, notably the Interdisciplinary Center for Defense and Security Studies (CIEDS, supported by the Ministry of the Armed Forces and the Defense Innovation Agency (AID)). It is behind the creation of the Interdisciplinary Center for Seas & Oceans, inaugurated in January 2025. Researchers from the school also collaborate on studies carried out by the Hi-Paris, IA Cluster laureate in 2024, E4C, or E4H centers, among others.

ENSTA results from the merger on January 1, 2025, of ENSTA Paris and ENSTA Bretagne. Its headquarters are located in Palaiseau (91), on the Paris-Saclay campus, and it has another campus in Brest. It is implementing a new unified engineering program on both campuses (Paris-Saclay and Brest) for the academic year 2026/2027.

Joining the school means becoming part of an institution committed to gender parity and professional equality, diversity, and support for its employees with disabilities, from recruitment and throughout their careers. To promote well-being at work, the school pursues an active policy regarding working conditions, based in particular on a healthy balance between personal and professional life.

Knowledge:

You possess the following skills:

• Higher education in fluid mechanics, energy, mechanics, maritime engineering, or equivalent field.

• Solid knowledge in fluid mechanics and naval hydrodynamics.

• Experience in numerical simulation of flows (CFD) and analysis of calculation results.

• Proficiency in at least one scientific programming language (Python, C/C++, Fortran…).

• Skills in processing, analyzing, and visualizing scientific data.

• Autonomy, scientific rigor, ability to work in a team and to conduct calculation and testing campaigns.

• Good level of scientific English.

The following skills would be appreciated:

• Skills in particle methods, particularly SPH method, or strong interest in their implementation.

• Experience in fluid mechanics experimentation.

• Knowledge in numerical optimization and/or geometry optimization.

• Knowledge in parallel/HPC computing

Software:

• Rhinoceros 3D, CATIA

• FINE/Marine

• Paraview, Tecplot

Know-how:

• Ability to plan time and organize oneself

• Ability to search for information

• Technical report writing skills

• Ability to grasp unfamiliar systems

Attitude:

• Autonomy

• Teamwork skills

• Proactive attitude

• Creative

• Flexibility and adaptability