Unsteady Flow Phenomena in Fluid Machinery Systems

Dear Colleagues,

Fluid machinery, serving as critical equipment in sectors such as energy, power, chemical processing, and aerospace, directly influences the technological level of major national projects and industrial systems. Within these machines, the presence of highly complex three-dimensional and unsteady turbulent flows represents a fundamental physical phenomenon that limits further improvements in performance and reliability.

Complex turbulent structures within blade passages—such as flow separation, vortex breakdown, secondary flows, and their interactions with wall-bounded boundary layers—are identified as root causes of hydraulic efficiency loss, broad-band vibration, and aerodynamic noise. Furthermore, under challenging operational conditions involving cavitation, particulate matter, multiphase media, or intense heat transfer, the strong coupling between turbulence and other physical phenomena results in highly nonlinear flow characteristics, posing significant threats to operational stability and component service life. Off-design, transient, and extreme operating conditions exacerbate turbulence-induced fluid–structure interaction vibrations, presenting major difficulties in design. With rapid advances in high-performance computing, refined flow measurement techniques, and data science methodologies, new opportunities are emerging for elucidating and controlling turbulent flows in fluid machinery. The integration of Large Eddy Simulation (LES), data-driven modeling, and advanced experimental diagnostics is expected to enable a deeper understanding and accurate prediction of these complex flows, thereby providing a scientific basis for the design of a new generation of highly efficient, low-noise, and reliable fluid machinery.

This Special Issue is dedicated to the topic of turbulence in fluid machinery and aims to collect the latest research achievements in this field. Original contributions are cordially invited from scholars on related fundamental theories, numerical simulations, experimental investigations, and innovative applications. Submissions addressing novel theories, methodologies, and technologies aimed at enhancing the performance and reliability of fluid machinery are particularly encouraged.

Prof. Dr. Zhengwei Wang
Dr. Yonggang Lu
Dr. Yongyao Luo
Dr. Hao Chang
Guest Editors

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• fluid machinery
• turbulence
• vortex dynamics
• multiphase flow
• fluid–structure interaction