08/06/2020
The Human Resources Strategy for Researchers

PhD in Fluid Mechanics

This job offer has expired


  • ORGANISATION/COMPANY
    CNRS
  • RESEARCH FIELD
    Chemistry
    Engineering
    Physics
  • RESEARCHER PROFILE
    First Stage Researcher (R1)
  • APPLICATION DEADLINE
    29/06/2020 23:59 - Europe/Brussels
  • LOCATION
    France › LE HAVRE
  • TYPE OF CONTRACT
    Temporary
  • JOB STATUS
    Full-time
  • HOURS PER WEEK
    35
  • OFFER STARTING DATE
    01/10/2020

OFFER DESCRIPTION

This PhD is financed by the project « PERCUSS » from Labex EMC3, in collaboration with CORIA (UMR6614). The employer is the CNRS. As part of this project, the PhD work will be performed in LOMC (UMR6294) with strong interactions with colleagues from the team “Atomisation and sprays” from CORIA, who have been developing for many years physical and numerical models dedicated to two-phase flows including a wide range of spatial and temporal scales such as atomization phenomena.
The PhD student will be integrated in the Marine Hydrodynamic group within the team HyTeR (Hydrodynamic, Turbulence and Reactivity) of LOMC. The group is specialised in physical and numerical modelling of flow/structure interactions in coastal zone with applications to renewable marine energy.
The PhD student will be part of doctorate school PSIME (PhysicS, EngineerIng, Materials, and Energy).

Objectives and context:
The PhD is part of the “PERCUSS” project financed by Labex EMC3, in collaboration with the CORIA laboratory (UMR6614, Rouen). The project objective is to study the effects of fluid aeration during the impact of large liquid sheets on energy recovery systems. The various scales characterizing such flows are an issue for their modelling and loads' characterization on impacted structures. The coordination of two PhD within the project will enable to develop new physical and numerical models, validated by means of physical tests, before their use in more realistic configurations.

Scientific approach:
Aerated impact will be mainly studied using an experimental and theoretical approach in our team at LOMC, whereas the team in CORIA will use a numerical modelling approach. Experimental and numerical data will be shared during the project in order to set-up a data base on aerated impacts for multi-scale numerical modelling of realistic configurations.
The objective of the physical modelling approach is to provide evolution laws of impact pressure as a function of different medium characteristics and for various reference configurations. Two configurations, corresponding to two measurement campaigns, will thus be tested:
• The first configuration consists in characterizing impact pressure of a falling object, equipped with pressure sensors, on an aerated medium. This configuration enables to control more easily the aeration rate of the medium and the impact velocity of the object. A wide range of impact velocity and aeration rate will be considered. Sound velocity in the medium will be monitored to estimate the aeration rate of the medium using Woods law. Impact pressure are measured using IEPE sensors, well suited for impact phenomena. Another parameter to be tested will be the size of the object from one pressure sensor (around 5mm) to instrumented plate increasing in size to several tens of centimetres.
• However, for wave breaking impact on offshore structures, the sheets of water impinging the structures are dislocated. The objective of the second configuration is to take into account such phenomena by considering an aerated jet impinging a fixed structure equipped with the same pressure sensors. This configuration is closer to impact cases of falling water sheet behind a dam or wave breaking impact. In this configuration, impact velocities will be considered optically. Moreover, an optical probe should be acquired to measure the aeration rate. One of the issue will be to determine and precisely characterize free surface fragmentation phenomena. This second experimental campaign will also enable to validate and feed numerical models in order to improve impact pressure prediction. To our knowledge, relatively few experiments have been performed with this configuration. The results will be compared with numerical results of Brauning et. al. [Brauning 2009], Guilcher et. al. [Guilcher 2010], Marrone et. al. [Marrone 2015] or Meringolo et. al. [Meringolo 2017] for instance.

Finally, the numerical models developed in CORIA, in which the aerated fluid is taken into account, will be used to simulate wave breaking impact on offshore structures. More precisely, the results will be compared with the experimental tests of Mai et. Al. [Mai2019] and their numerical results. Reaching larger aeration rate than those of Mai et. al. will be one objective of this work. This last step will constitute the last task of the PhD.
For the work mentioned above, the PhD student will have to conceive and realize the experimental set-up.

The results will be presented at international and national conferences in the community of multiphase flows and hydrodynamics, and will be published in peer-review publications.

References :
[Brauenig 2009] J.-P. Braeunig, L. Brosset, F. Dias, J.-M. Ghidaglia, Phenomenological Study of Liquid Impacts through 2D Compressible Two-fluid Numerical Simulations, in: Proceedings of the Nineteenth (2009) International Offshore and Polar Engineering Conference, The International Society of Offshore and Polar Engineers (ISOPE), Osaka, Japan, 2009, pp. 21–29, iSBN : 978-1-880653-53-1
[Guilcher 2010] P. Guilcher, G. Oger, L. Brosset, E. Jacquin, N. Grenier, D. Le Touzé, Simulation of liquid impacts with a two-phase parallel SPH model, in: Proceedings of 20th International Offshore and Polar Engineering Conference, June 20-26, Bejing, China, 2010
[Mai 2019] T. Mai, C. Mai, A. Raby, and D. M. Greaves, 'Aeration effects on water-structure impacts: Part 2. Wave impacts on a truncated vertical wall', Ocean Engineering, vol. 186, p. 106053, Aug. 2019.
[Marrone 2015] S. Marrone, A. Colagrossi, A. Di Mascio, D. Le Touzé, Prediction of energy losses in water impacts using incompressible and weakly compressible models. Journal of Fluids and Structures 54 (2015) 802–822
[Meringolo 2017] D. Meringolo, A. Colagrossi, S. Marrone, F. Aristodemo, On the filtering of acoustic components in weakly-compressible SPH simulations, Journal of Fluids and Structures 70 (2017) 1 – 23.

More Information

Additional comments

Skills required:

The PhD candidate should be graduated in Fluid Dynamics from reputed University or Engineering Schools. The successful candidate will have strong background in Fluid Dynamics, experimental technics and good communication skills both orally and in terms of written English for the scientific presentation of his/her work in congress or scientific papers. We are looking for a young researcher who will be dedicated to his/her work, with strong analytical and synthesis skills, and who is also able to work autonomously during the design and manufacturing of his/her scientific experimental campaign. Additionally, the candidature should be able to work in a good team spirit on such a multi-disciplinary project.

Documents to be provided:
Applicants should send :
1. A clear and detailed Curriculum Vitae
2. A cover letter stating his/her motivation for the concerned PhD proposal
3. The contact inform of two referees that will be able to support his/her application
4. The grade transcript of his/her last 2 years of Master degree
5. A one-page abstract of his/her Master thesis.

Web site for additional job details

Required Research Experiences

  • RESEARCH FIELD
    Engineering
  • YEARS OF RESEARCH EXPERIENCE
    None
  • RESEARCH FIELD
    Chemistry
  • YEARS OF RESEARCH EXPERIENCE
    None
  • RESEARCH FIELD
    Physics
  • YEARS OF RESEARCH EXPERIENCE
    None

Offer Requirements

  • REQUIRED EDUCATION LEVEL
    Engineering: Master Degree or equivalent
    Chemistry: Master Degree or equivalent
    Physics: Master Degree or equivalent
  • REQUIRED LANGUAGES
    FRENCH: Basic
Work location(s)
1 position(s) available at
LABORATOIRE ONDES ET MILIEUX COMPLEXES
France
LE HAVRE

EURAXESS offer ID: 530341
Posting organisation offer ID: 15674

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