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Postdoc on Modelling and HPC numerical simulations of Quantum Turbulence. Models for coupling GrossPitaevskii and NavierStokes equations. Univ. Rouen (France)
Du 1 décembre 2019 au 31 décembre 2020
Rouen, France
For further information contact :
ionut.danaila@univrouen.fr
marc.brachet@gmail.com
This study is part of a national (ANR) research program entitled QUTEHPC (QUantum Turbulence Explo ration by HighPerformance Computing). The project gathers 10 researchers from physics and mathematics and is aimed at providing a new stateoftheart for the mathematicalphysical modelling and High Perfor mance Computing (HPC) of Quantum Turbulence (QT) in superfluid quantum fluids, such as superfluid He
PostDoctoral position for 12 months, available immediately
Modelling and HPC numerical simulations of Quantum Turbulence. Models for coupling GrossPitaevskii and NavierStokes equations.
Advisors :
Ionut DANAILA
Laboratoire de mathématiques Raphaël Salem, Rouen France
ionut.danaila@univrouen.fr
Marc BRACHET
Laboratoire de Physique Statistique Ecole Normale Supérieure France
marc.brachet@gmail.com
Context:
This study is part of a national (ANR) research program entitled QUTEHPC (QUantum Turbulence Explo ration by HighPerformance Computing). The project gathers 10 researchers from physics and mathematics and is aimed at providing a new stateoftheart for the mathematicalphysical modelling and High Perfor mance Computing (HPC) of Quantum Turbulence (QT) in superfluid quantum fluids, such as superfluid He lium (He) and atomic BoseEinstein condensates (BEC). The primary focus of the project is the study of QT in liquid Helium. More information on the project can be find at http://qutehpc.math.cnrs.fr/
Research topic:
Superfluid He is a very low temperature system in which two interpenetrating fluids with different behaviors exist: a normal viscous flow, governed by the NavierStokes (NS) equation, and an inviscid (zero viscos ity) superfluid flow, introducing quantum effects and governed by the GrossPitaevskii (GP) equation. QT is a highly multiscale phenomenon, ranging from Angstrom for the superfluid vortex diameter, to centime ters/meters for the size of the cryostat, which explains why mathematicalphysical models and simulations covering accurately all scales do not exist nowadays.
In the framework of the QUTE project, several numerical codes using spectral methods are available to solve the models at the two ends of this multiscale description: the GP model for the superfluid fraction and the NS model for the normal viscous fluid. Codes implementing the twofluid HVBK model are also available in the project.
Objectives:
The objective of the postdoc is to address theoretically and numerically the critical gap between a closeup view of the interaction between normalfluid and quantized superfluid vortices and a coarsegrained represen tation of QT dynamics. The final goal of the project is to offer a unified theoretical and numerical representa tion of QT, describing accurately all scales present in the system.
For this purpose, the following steps will be taken:
• Explore existing numerical systems in the QUTEHPC project to perform large HPC simulations for limiting (GP and twofluid HVBK) models. Explore QT in the zerotemperature limit (GP model) using high space and time resolution HPC computations going beyond existing simulations. Include thermal effects in the GP model and the GPS (GrossPitaevskii Simulator) code.
• Perform HPC simulations with the twofluid HVBK model. Ensure the HPC compatibility between the (existing) NS solver and the GPS solver.
• Model the coupling between numerical solvers for superfluid (GP) and normal fluid (NS) to simulate the QT system up to the intervortex length scale and beyond.
Requirements:
The successful candidate is expected to hold (or about to have) a PhD in the area of computational physics or applied mathematics. Programming experience is essential. Experience in using highperformance computing facilities (HPC) would be an advantage.
Applicants should email a statement of interest, a CV, and a list of publications.
Practical information:
Salary: ~ 2100€net/month
Location: Rouen, France
Dates: available immediately for 12 months (reneweble another one year)
Contact:
ionut.danaila@univrouen.fr
marc.brachet@gmail.com
Bibliography (with links when available) :
QUTEHPC ANR project.
P. Parnaudeau, J.M. SacEpe, A. Suzuki, GPS: an efficient and spectrally accurate code for computing GrossPitaevskii
Equation, International Super Computing (ISC) Frankfurt (Germany), July 1216, 2015.
G. Vergez, I. Danaila, S. Auliac and F. Hecht, 2016. A finiteelement toolbox for the stationary GrossPitaevskii equation
with rotation, Computer Physics Communications, 209, p. 144–162, 2016.
Salort, J., Chabaud, B., Lvque, E. and Roche, P.E., 2012. Energy cascade and the fourfifths law in superfluid turbulence.
Europhysics Letters, 97:34006.
Clark di Leoni, P. and Mininni, P.D. and Brachet, M.E., 2015. Spatio temporal detection of Kelvin waves in quantum turbulence simulations. Phys. Rev. A, 95:053636.
Clark di Leoni, P. and Mininni, P.D. and Brachet, M.E., 2018. Finitetemperature effects in helical quantum turbulence, Phys. Rev. A 97:043629.
Tsubota, M., 2006. Quantized vortices in superfluid helium and BoseEinstein condensates, Journal of Physics: Confer ence Series, 31(1):88.
Tsubota, M., Fujimoto, K. and Yui, S., 2017. Numerical Studies of Quantum Turbulence, J. of Low Temperature Physics, 188:119189.
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 Postdoc_2019_QUTE.pdf (PDF, 66 Ko)