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PhD Numerical simulations and field measurements of frosty events in viticultural area protected by wind machine farm: Application to the Quincy vineyard - IRSTEA, Rennes

Du 1 mars 2019 au 30 septembre 2019

Starting in October or November 2019.
IRSTEA, Rennes, France

For further information, please contact
Dominique Heitz (dominique.heitz@irstea.fr)
Johan Carlier (johan.carlier@irstea.fr)
Emmanuel Buisson (emmanuel.buisson@weather- measures.com).

This PhD position is opened within the SICTAG project (2019-2022) for “Innovative and connected decision aid system and efficient real-time management of wind tower farm in Centre-Val de Loire region”. The Phd Student is

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PhD Position

Numerical simulations and field measurements of frosty events in viticultural area protected by wind machine farm: Application to the Quincy vineyard

Context: Fight against frost is a considerable economic challenge in viticulture. A harvest loss of 30% in the Quincy vineyard due to frost represents a turnover loss of about 3 million euros, while the vineyard represents only 1 to 2% of the vineyards in the Centre-Val de Loire region. These losses impact the wine growers, but also all the local economy. Reducing the frost damage and optimizing frost-fighting methods are therefore important issues in the regional viticultural sector.

One of the frost-fighting methods applied in the Quincy vineyard is the wind machine: a fan at the top of a mast mixing the colder air near the ground with the warmer air from the upper portions of the inversion layer, raising air temperatures around the trees by a few degrees. Over the last 15 years, Cuma collective has upgraded wind machine farm up to 60 units with the support of the Regional Council. However, efficiency and management of these equipments question the wine growers with regard to their practices and experiences. In addition, there are few reliable and independent studies that have been carried out on the efficiency of different anti-frost wind machine systems.

Assignment and activities: Within the SICTAG project, the goal of the thesis is to improve the efficiency of the wind farm and to foster collaboration between partners. In particular, we want to forecast frosty events and to propose an efficient implantation and setting of wind machines for a given viticultural area, mainly characterized by a crop, a climate and a topography. To do this, we want:

  • to determine the frost risk by modeling frost events on a viticultural area with a downscaling of a regional weather model coupled with local measurements and numerical simulations. Various scenarios of frosty events occurring in the Quincy vineyard will be measured and simulated. This work will notably make it possible to propose a sensor implantation on the vineyard for a better evaluation of the frost risk and thus more relevant decision aid for triggering wind machine;

  • to analyze and understand the effects of wind machine on the air near the vine, in particular the effect of thrust, inclination and rotation of the fan on the generated flow (spatial range, turbulent mixing, etc.). The wind machine characterization by field measurements of and the frost risk simulation should allow to propose an efficient implantation and setting of wind machines in the area concerned. It must also make it possible to implement wind machine in the local climate simulator to test, after checking representativeness of the wind machine modeling, the ability of the farm to reject frost events.

    The overall approach must be considered in the perspective of wind machine farm automation by individually controlling the wind machine (thrust, inclination and rotation) through field measurements to prevent the frost at a lower energy cost. A bibliographic analysis should enable the doctoral student to understand the subject. Particular care must be taken in the scientific exploitation of the work by the writing of the thesis and publications that will be submitted to peer-reviewed international journals. An effort should also be made to present the results at conferences, workshops and project meetings.

    Skills: We are looking for a highly motivated student who has completed a MSc or equivalent degree in fluid mechanics and computational fluid dynamics, experienced in the use of Finite Volume Methods (OpenFOAM), able to communicate on a regular basis with supervisors and end-users, receptive to directions and feedback from supervisors, and able to clearly and concisely communicate in English in written and spoken form.

    Contract type: CIFRE fellowship (3 years full time work contract with a French company)Remuneration: Monthly salary after taxes around 1500€

    Starting date: October or November 2019

    If you are interested in this PhD position, please send your application (provide a CV detailing your past experience as well as a motivation letter that described why you are interested in this position in particular) to Dominique Heitz (dominique.heitz@irstea.fr), Johan Carlier (johan.carlier@irstea.fr) and Emmanuel Buisson (emmanuel.buisson@weather- measures.com).