Dr Benjamin Bugeat

I am a Lecturer at the University of Leicester (since 2023), specialising in the stability and transition to turbulence of shear flows, particularly in the presence of density and viscosity stratifications. I use computational and theoretical approaches, such as modal and non-modal stability analysis, resolvent analysis, and direct numerical simulation. I obtained my PhD at Sorbonne Université, followed by postdoctoral research at the University of Cambridge and TU Delft.

My research focuses on the stability and transition to turbulence in shear flows with strong stratifications of fluid properties such as viscosity and density. This work is motivated by recent advances in the study of the hydrodynamic behaviour of supercritical fluids in transitional regimes, a topic that remains largely unexplored. In the presence of heat transfer, these fluids exhibit steep, localised variations of properties in the region of the phase diagram called the Widom line. These variations can significantly modify the flow dynamics, leading to the emergence of a new instability associated with the unique characteristics of supercritical fluids.

Using numerical and theoretical approaches, I examine simplified models that capture the key features of these flows, with the aim of improving our understanding of the physical mechanisms responsible for energy growth. This fundamental research contributes to a better identification of laminar and turbulent regimes in supercritical fluids and will ultimately support the development of more efficient heat exchangers operating at lower Reynolds numbers.

P. C. Boldini, R. Hirai, B. Bugeat, and R. Pecnik (2025) First-order buoyancy correction of modal instabilities in stratified boundary layers, Journal of Fluid Mechanics

P. C. Boldini, B. Bugeat, J. W. R. Peeters, M. Kloker and R. Pecnik (2025) Direct numerical simulation of complete transition to turbulence with a fluid at supercritical pressure, Journal of Fluid Mechanics, vol 1025, A59

P. C. Boldini, B. Bugeat, J. W. R. Peeters, M. Kloker and R. Pecnik (2024) Transient growth in diabatic boundary layers with fluids at supercritical pressure, Physical Review Fluids, 9(8), 083901

B. Bugeat, P. C. Boldini, A. M. Hasan and R. Pecnik (2024) Instability in strongly stratified plane Couette flow with application to supercritical fluids, Journal of Fluid Mechanics, vol. 984, A31

P.C. Boldini, B. Bugeat, J.W.R. Peeters, M. Kloker and R. Pecnik (2024) Direct numerical simulations of K-type transition in a flat-plate boundary layer with supercritical fluids, IUTAM Symposium on Laminar-Turbulent Transition, 255-261

B. Bugeat, U. Karban, A. Agarwal, L. Lesshafft and P. Jordan (2024) Acoustic resolvent analysis of turbulent jets, Theor. Comput. Fluid Dyn. 38, 687–706

M. Draskic, B. Bugeat and R. Pecnik (2024) The steady behaviour of the supercritical carbon dioxyde natural convection loop, Energy (2024): 130735

U. Karban, B. Bugeat, A. Towne, L. Lesshafft, A. Agarwal and P. Jordan. (2023) An empirical model of noise sources in subsonic jets, Journal of Fluid Mechanics, vol. 965, A18

P.C. Boldini, R. Gaspar, B. Bugeat, P. Costa, J.W.R Peeters and R. Pecnik. (2023) Direct numerical simulation of H-type transition in a flat-plate boundary layer with supercritical fluids, 14th international ERCOFTAC Symposium on Engineering Turbulence Modelling and Measurements

B. Bugeat, P.C. Boldini and R. Pecnik. (2022) On the new unstable mode in the boundary layer flow of supercritical fluids, 12th International Symposium Turbulence and Shear Flow Phenomena

B. Bugeat, J.-C. Robinet, J.-C. Chassaing and P. Sagaut. (2022) Low-frequency resolvent analysis of the laminar shock wave / boundary layer interaction, Journal of Fluid Mechanics, vol. 942, A4

U. Karban, B. Bugeat, E. Martini, A. Towne, A.V.G. Cavalieri, L. Lesshafft, A. Agarwal, P. Jordan and T. Colonius. (2020) Ambiguity in mean-flow-based linear analysis, Journal of Fluid Mechanics, vol. 900, R5

B. Bugeat, J.-C. Chassaing, J.-C. Robinet and P. Sagaut. (2019) 3D optimal forcing and response of the supersonic boundary layer, Journal of Computational Physics, vol 398, 108888

EG2132: Fluid Dynamics and Aerodynamics
EG3421: Flight Dynamics and Control
EG3005: Third-Year Project Supervision
FS0024: Aerodynamic Lab