Assistant Professor In laboratoire de mécanique des fluides de Lille, Ecole Centrale Lille (09/2020)

Fixed term assistant professor as agrégé (09/2018-08/2020) in ENS Lyon

ATER in institut PPrime (09/2017-08/2018)

Associate researcher in Frankfurt (10/2014-08/2017)

post doc (10/2012-09/2014)

Thesis (2009-09/2012)

Publications (Output of Doctorate, of my Post doctorate, of my position in Frankfurt):

1. D P. Manneville, J. Rolland, On modelling transitional turbulent flows using under-resolved direct numerical simulations: the case of plane Couette flow, Theor. Comput Fluid Dyn. 25, 407-420 (2010). On ArXiv, On HAL.
2. D J. Rolland, P. Manneville, Ginzburg--Landau description of laminar-turbulent oblique band formation in transitional plane Couette flow, Eur. Phys. J B 80, 529-544 (2011). On ArXiv, On HAL.
3. D J. Rolland, P. Manneville, Pattern Fluctuations in Transitional Plane Couette Flow, J. Stat. Phys. 142 p 577 (2011). On ArXiv, On HAL .
4. D J. Rolland, Turbulent spot growth in plane Couette flow: statistical study and secondary instability, Fluid Dyn. Res. 46, 015512 (2014). On ArXiv, On HAL .
5. D J. Rolland, Formation of spanwise vorticity in oblique turbulent bands of transitional plane Couette flow, part 1: numerical experiments, Eur. J. Mech. B Flu. 50C, 52-59 (2015). On Arxiv, On Hal.
6. D J. Rolland, Formation of spanwise vorticity in oblique turbulent bands of transitional plane Couette flow, part 2: modelling and stability analysis, Eur. J. Mech. B Flu. 56, 13-27 (2015). On Arxiv.
7. D J. Rolland, Mechanical and statistical study of the laminar hole formation in transitional plane Couette flow, Eur. Phys. J. B, 88: 66 (2015). On Arxiv, on HAL.
8. D J. Rolland, Stochastic analysis of the time evolution of Laminar-Turbulent bands of plane Couette flow , Eur. J. Phys. E 38: 121 (2016), On arxiv.
9. P J. Rolland, E. Simonnet, Statistical behavior of adaptive multilevel splitting algorithms in simple models, J. Comp. Phys, 283, 541-558 (2015). On Arxiv.
10. P J. Rolland, F. Bouchet, E. Simonnet, Computing transition rates for the 1-D stochastic Ginzburg-Landau-Allen-Cahn equation for finite-amplitude noise with a rare event algorithm, J. Stat. Phys. 162, 277-311 (2016). On Arxiv, On Hal.
11. F S. Hein, J. Rolland, S. Borchert, L. Schoon, C. Zülicke, U. Achatz, Spontaneous inertia-gravity wave emission in the differentially heated rotating annulus experiment, J. Fluid Mech. 838, 5-41 (2018). On uni. Frankfurt website.
12. P J. Rolland, extremely rare collapse and build-up of turbulence in stochastic models of transitional wall flows, Phys. Rev. E. 97, 023109 (2018). on hal.
13. D J. Rolland, Finite size analysis of a double crossover in transtional wall turbulence, J. Stat. Mech. 093207 on arxiv
14. P F. Bouchet, J. Rolland, E. Simonnet, A rare event algorithm links transitions in turbulent flows with activated nucleations, Phys. Rev. Lett. 122, 074502 (2019), sur arxiv, sur hal
15. P F. Bouchet, J. Rolland, J. Wouters, Rare events sampling methods, Chaos 29, 080402 (2019). Introduction of a special issue of the journal Chaos on rare events sampling methods, coedited par F. Bouchet, J. Rolland and J. Wouters.
16. P E. Simonnet, J. Rolland, F. Bouchet, Multistability and rare spontaneous transitions in barotropic β-plane turbulence, J. Atmo. Sci. 78 (6), 1899 - 1911 (2021). Sur Arxiv (2020).
17. P J. Rolland, Collapse of transitional wall turbulence captured using a rare events algorithm ,J. Fluid Mech. 931, A22 (2022) On Arxiv (2021).
18. A. Fuchs, C. Herbert, J. Rolland, M. Waechter, F. Bouchet, J. Peinke, Instantons and the path to intermittency in turbulent flows , Phys. Rev. Lett. 129, 034502 (2022). on arxiv (2021).
19. D. Lucente, J. Rolland, C. Herbert, F. Bouchet Coupling rare events algorithms with data-based learned committor functions using the analogue Markov chain, J. Stat. Mech. 083201 (2022). on arxiv (2021).
20. J. Ge, J. Rolland, J.-C. Vassilicos, The production of uncertainty in three-dimensional Navier--Stokes turbulence, J. Fluid Mech. 977 A 17 (2023). on arxiv, on HAL

1. J. Rolland Does rare, noise-induced, bypass transition in plane Couette flow bypass instantons? arxiv:2401.055555 (2024). sur arxiv, sur HAL

1. P D. Lucente, S. Duffner, C. Herbert, J. Rolland, F. Bouchet, Machine learning of committor functions for predicting high impact climate events, 9th international workshop on climate informatics (2019). on arxiv

1. M. Rabaud, F. Moisy, J. Rolland, Mesure de la déformation d’une surface libre par analyse du déplacementapparent d’un motif aléatoire de points, Compte rendu du 18ème congrès français de mécanique, grenoble (2007). on line
2. J. Rolland, P. Manneville, Modèle de Landau–Langevin pour la description des bandeslaminaires-turbulentes dans l’écoulement de Couette plan, Comptes rendus des rencontres du non-linéaire, 145-150 (2011) On the website of the Rencontres du Non-Linéaire.
3. J. Rolland, P. Manneville, Turbulent pattern formation in plane Couette flow: modelling and investigation of mechanisms, J. Phys.: Conf. Ser. 318 032034 (2011).
4. J. Rolland, Analyse taille finie d'une crise de fluctuations dans l'écoulement de Couette plan transitionel, comptes rendus des rencontres du non-linéaire, 131-136 (2015). On the website
5. J. Rolland, F. Bouchet, E. Simonnet, Etude systematique des transitions dans l'équation de Ginzburg-Landau stochastique par l'algorithme adaptive multilevel splitting , Comptes rendus des rencontres du non-linéaire, 17-22 (2014). On the website, See also the proceedings on the RNL website.
6. J. Rolland, Relaminarisations rares dans un modèle de turbulence de paroi transitionnelle: au delà des expériences et des simulations numériques directes, Comptes rendus des rencontres du non-linéaire, 73-78 (2017). On the Website.

Rare and extreme events

A noisy system which has several "equilibrium positions" can be metastable. This means that it will stend most of its time in either of the two states, and, from time to time, transition from one state to another. This situation is often found in turbulent flows of geophysical or aerodynamic relevance, where turbulent builds up several metastable large scale circulations and rarely (but importantly) drives transitions between them. Sampling efficiently these transitions in numerical simulations, in order to study their properties, is therefore a key challenge.

Transition to wall turbulence

Wall flows such a plane Couette flow (illustrated on the left) display a peculiar transition to turbulence. In many cases, the laminar base flow is linearly stable. This means that the transition to turbulence is subcritical: only finite amplitude initial conditions or forcing can lead the flow to turbulence. Moreover, turbulent and laminar flow can coexist in time and space. In transitional plane Couette flow this coexistence takes the form of oblique laminar-turbulent bands.

Waves in geophysical fluid dynamics

Geophysical flow are typically flows in a rotating frame (caracterised by the coriolis parameter, ƒ) with a stratification (caracterised by the Brunt-Vaisala frequency N). In atmospheres and oceans, we always have ƒ≤ N.

In Ecole centrale Lille (since 2020)

In the international master of turbulence (since 2020)

At ENS de Lyon (2018-2020)

1. Seminar in institut d'Alembert, on the 02/05/2019 link on the youtube channel of the seminar of institut d'Alembert
2. LMFL Webinar, on the 10/21/2021 link on the youtube channel of the LMFL webinar