JFM Rapids is a well-established section in the Journal of Fluid Mechanics that continues to provide a highly visible venue for short, high-quality, articles addressing timely research challenges of broad interest. In this annual collection, the editors of JFM Rapids each explain why they selected one article that presents exciting results with exceptional impact on currently active fluid mechanics research.

Read on to discover the selected articles and the editors’ insights:

Elisabeth Guazzelli:

• Dynamics of rotating helices in viscous fluid by Chijing Zang, Luke Omodt, Moumita Dasgupta, and Xiang Cheng

“This manuscript presents combined experiments and modelling on the interaction of rotating helices in a viscous fluid, identifying a critical phase difference at which hydrodynamic coupling vanishes despite the helices being close together. The results provide valuable insights into low-Reynolds-number propulsion and can be used to further explore the efficiency of swimmers with helical flagella and the design of pumps.  As a Rapids paper, it effectively conveys these impactful findings to a wide readership interested in micro-swimmers, flagella and low-Reynolds-number fluid dynamics.”

Detlef Lohse:

• Multiple states in centrifugal convection by Zhongzhi Yao, Mohammad S. Emran, Andrei Teimurazov, Marvin Kriening, Jiaxing Song, and Olga Shishkina

“In recent years it has become clear that different turbulent states can coexist for given control parameters, i.e., multistability in turbulent flow got firmly established. Moreover, also recently, Chao Sun and coworkers have illuminated the physics of turbulent centrifugal convection with the help of a wonderful new experimental facility they had developed for that purpose. The new JFM Rapids by Yao et al. brings together these two new and exciting strings in turbulence research. By a combination of detailed and systematic numerical simulations and analytical theory they show which different turbulent states can coexist in centrifugal convection and in addition provide a predictive framework – an exemplary JFM Rapids article.”

Dan Henningson: 

• Guided-jet waves generated by an acoustic source in a jet at a Mach number of 0.95 by Christophe Bogey.

“The paper proposes a model problem for guided jet waves, related to acoustic resonances inside the potential core leading to peaks in acoustic spectra, associated to undesirable additional jet noise. The model in the work is based on the linearised response of a parallel jet to harmonic excitation. Despite the simplicity of the model, it shows compelling evidence that important key features are already present in such a simplified setting, features whose appearances in a number of earlier experiments were not understood.”

Lian-Ping Wang:

• Experimental investigation of cylindrically divergent Rayleigh-Taylor instability on a water-air interface by Yu Liang and Xisheng Luo

“This study utilizes a novel hydrophobic interface control technique to experimentally investigate cylindrically divergent Rayleigh–Taylor instability at a water–air interface. This study has significant implications for inertial confinement fusion and astrophysical hydrodynamic mixing. Key findings include the identification and characterization of ‘freeze-out’ and oscillatory perturbation growth, offering new insights into the role of surface tension in cylindrical geometries. Linear and weakly nonlinear theoretical models were developed to predict the experimental observations.”

Sarah Waters: 

• Choking the flow in soft Hele-Shaw cells: the role of elastomer geometry by Lewis Melvin, Gunnar Peng, Draga Pihler-Puzović and Finn Box

“This fascinating study investigates flow-induced choking in Hele-Shaw cells in which a viscous fluid flows in the gap between a rigid plate and a confined elastomer block.  Using theory and computations, the authors show that choking occurs for flow rates above a critical value that depends on the relative depth of the elastomer.  This interesting and impactful Rapids paper offers fundamental insights into fluid-structure interaction phenomena occurring in geological, microfluidic and biological systems.”

Tamer Zaki:

• Knowledge-integrated additive learning for consistent near-wall modelling of turbulent flows by Fengshun Zhang,  Zhideng Zhou, Xiaolei Yang and Guowei He

“Modeling of near-wall turbulence enables large eddy simulations in flow regimes that are otherwise inaccessible using wall-resolved computations.  This paper leverages the knowledge from simplified boundary-layer equations and machine learning to build a data-driven wall model.  The model progressively adds forcing terms for non-equilibrium effects, including pressure gradient and separation, and a distance function enables the fusion of the various effects.  The work naturally bridges classical and data driven strategies for advancing wall-modeled simulations of non-equilibrium flows.”  

We hope these selected articles will inspire more researchers to submit their results to JFM Rapids.

Read these articles in one collection along with the chosen articles from previous years.

Read previous blogs in this series:

• JFM Rapids: The Editors’ Insights 2023
• JFM Rapids: The Editors’ Insights 2024
• JFM Rapids: The Editors’ Insights 2025

Concise, high impact research in Journal of Fluid Mechanics

• Fast: First decision in 30 days
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• Dedicated: Editors deal exclusively with Rapids submissions
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