Bagheri E, Becker S, Schlatter P (2026)
Publication Type: Journal article
Publication year: 2026
Book Volume: 1033
Article Number: R3
Turbulence-induced friction is a significant contributor to energy consumption in the fluid-transport and piping industries. Here, we describe a passive approach to suppress turbulence and reduce friction: we show that a local increase in streamwise flow curvature, combined with changing a circular cross-section to an oval, relaminarises turbulent flow in curved pipes. We exemplify this effect in a 180° bend at Re D = 10000 and 20000 (based on bulk velocity UB and pipe diameter $D$), well above the limit for sustained turbulence in straight pipes and the linear stability limit in 180° bends. Curvature inhibits streamwise Reynolds stresses, and cross-sectional modifications weaken the unstable secondary flow, together disrupting the near-wall regeneration cycle and collapsing turbulence. Simulations and experiments confirm that these geometric modifications suppress turbulence and reduce pressure loss by 53% and 36% compared with the baseline 180° bend and a fully developed straight pipe of equal length, respectively. The results establish a passive, mechanism-based route to relaminarisation in curved pipes with implications for energy-efficient control in other wall-bounded flows with curvature.
APA:
Bagheri, E., Becker, S., & Schlatter, P. (2026). Collapse of turbulence in optimised curved pipe flow. Journal of Fluid Mechanics, 1033. https://doi.org/10.1017/jfm.2026.11427
MLA:
Bagheri, Eman, Stefan Becker, and Philipp Schlatter. "Collapse of turbulence in optimised curved pipe flow." Journal of Fluid Mechanics 1033 (2026).
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