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Job Record #16828
TitleIndoor Air Quality protection through Soils Depressurisation
CategoryPostDoc Position
EmployerLEGI, Université Grenoble Alpes
LocationFrance, Grenoble
InternationalYes, international applications are welcome
Closure Date* None *
“High performance simulation and optimization of an active device for preserving the quality of indoor air with respect to emissions from polluted soils"

Context: The quality of indoor air is a public health issue. The impacts on indoor air quality of anthropogenic soil pollution still remains a subject that is not well understood by most professionals, in particular for constructions on sites with environmental liabilities. Among the constructive measures that can be implemented (ADEME / BATICOV, 2017), Soil Depressurization Systems (SDS) makes it possible, by depressurizing the base floor, to reverse parasitic air flows between the ground and the floor interior environment through the slab.

Moreover, when these devices are deployed, they are generally coupled to a geomembrane in order, on the one hand to limit the diffusive transfer of volatile pollution and on the other hand, to compensate for any insufficiencies of the depression generated by the SDS. There are no standards or technical guide (except for passive SDS) both in France and abroad to size these systems. The long-term objective of the project is to develop a calculation tool allowing the sizing of these devices for land-use buildings of several hundred m². The question is then the organization of the network of drains, the characteristics of these drains and of the gas extractor to be put in place. footprint of several hundred m².

Description of the work to be carried out: Numerical simulations will be carried out with OpenFoam to understand the operation of an SDS, the aeraulic flows induced in the soils, and their effects on the protection of the air quality above the slab. These numerical simulations can be compared with results from an experimental platform implemented elsewhere by the industrial partners of the project. Two scales will be investigated:

-	At the scale of the drain and inter-drains (a few m2), 3-dimensional simulation of the flows in mini-drains, the soils (compacted backfill and soils in place) and the geotextile will be carried out. Those simulations will be performed taking into account local interactions between drains, turbulence in the drains and the configuration of the drain network (diameter of drains, stainers geometry, inter-drain spacing). At this level, simplifying modeling assumptions will be the subject of particular attention (representation of the perforated drain by an equivalent porous cylinder and modeling of external corrugations via an equivalent roughness in the turbulence model). The results will be evaluated in terms of pressure distribution in the drains in order to define the conditions required to obtain an effective depressurization field in the surrounding soil.

-	At a larger scale (around one hundred m², corresponding to the experimental platform), simulations will be carried out on the entire device to study gas flows and the convective-dispersive transport of the main pollutant. The source of the pollutant will be represented by an imposed concentration in the soil gases (dissolution, volatilization and sorption will not be represented). The three-dimensional schematization model will integrate the entire system including the geomembrane as well as the upper “layers” that are the low floor (concrete) and an air boundary layer above allowing emissions to be assessed to the interior air for the different conditions of the experiments.

Host laboratory: The candidate will be integrated into LEGI within the EDT team. The candidate will benefit from the strong dynamics existing in the laboratory around the development of resources with OpenFoam. He will be able to rely on the internal resources of LEGI (machines with ten nodes and twenty cores per node) as well as on the regional network UMS GRICAD (GRenoble-alpes Infrastructures of Intensive Calculation and Data) and its computing pole for massively parallel calculations, a pole in which LEGI is strongly involved. The subject deals with an important societal and environmental issue (indoor air quality). Through this project, the candidate will interact with industrial partners at the forefront of this subject (Ginger-Burgeap, Terra Environment, Terragos)

Applicant profile : The candidate must hold a doctorate in fluid mechanics or numerical simulation applied to mechanics. A strong interest in numerical modeling and expertise in fluid mechanics are particularly important. Experience with open source simulation software Openfoam would be highly appreciated. The candidate must be able to work in a dynamic environment made up of several actors. Among the other qualities sought, autonomy, good communication and writing skills (with a particular expectation on the quality of deliverables and scientific articles) are expected. Very important : a good level of written french for foreign applicant is desirable as some deliverables for ADEME will have to be in french) 

Conditions: This 12-month full-time position is funded by ADEME under the PRIMEQUAL call (BARIAIR project). It will be located at the Laboratory of Geophysical and Industrial Flow (LEGI) of the University of Grenoble-Alpes. The desired start date for the position is April 2021. However, depending on the candidate's availability, the exact start date can be negotiated. The gross salary will be around € 2,680 / month (net salary around € 2145). The successful candidate will be supervised by Dr Philippe SECHET ( in collaboration with Cyrille Bonamy ( He will also collaborate with other industrial partners

Instructions for applying: Applications should be sent by email only to Philippe Séchet ( and Cyrille Bonamy ( with all the documents necessary to assess the relevance of the application (cover letter, full CV and list publications, selected publications, names and contact details of two referees and / or letters of recommendation). Applicants will be contacted for an interview with an ad hoc committee.

Contact Information:
Please mention the CFD Jobs Database, record #16828 when responding to this ad.
NameDr Philippe SECHET
Email ApplicationYes
AddressPhilippe SECHET
1209-1211 rue de la Piscine, Domaine Universitaire
38400 Saint Martin d'Hères, France
Record Data:
Last Modified17:26:25, Friday, November 06, 2020

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