MEchanics GAthering –MEGA- Seminar: A triple source model of pressure fluctuation analysis for a mixed-flow pump
Event details
| Date | 24.09.2026 |
| Hour | 12:30 › 13:30 |
| Speaker | Bingfu Han (HEAD, EPFL) |
| Location | Online |
| Category | Conferences - Seminars |
| Event Language | English |
Abstract: Pressure fluctuations in turbomachinery arise from the combined effects of blade rotation, coherent flow instabilities and broadband turbulence, making their physical origins difficult to isolate. This presentation introduces a triple source model for pressure fluctuations on the stationary shroud wall of a mixed-flow pump. The model decomposes the measured signal into a kinematic non-uniform component caused by the steady blade sweep, a phase-locked flow-synchronous component, and a non-phase-locked flow-asynchronous component. Applied to experimentally validated stress-blended eddy simulations, the framework shows that synchronous contributions account for more than 90% of the fluctuation energy along the tip leakage vortex trajectory. It also reveals destructive interference between the steady pressure footprint and the dynamic vortex response, with a local cross-correlation coefficient of -0.26. Pressure Poisson equation analysis then links each component to its fluid-dynamic source: mean momentum flux drives the non-uniform pressure asymmetry, periodic vortex-turbulence interaction dominates the synchronous response, and nonlinear turbulent interactions generate the broadband component. These results identify the tip leakage vortex as the common physical nexus of the three sources. The framework provides a quantitative basis for diagnosing turbomachinery unsteadiness and for developing targeted strategies to reduce pressure fluctuations, vibration and noise.
Biography: Bingfu Han has been a direct-entry PhD candidate in Energy and Power Engineering at Tsinghua University, Beijing, China, since 2022, under the supervision of Prof. Lei Tan. He is currently a visiting PhD researcher in the HEAD Lab at EPFL from July to October 2026, hosted by Prof. Eunok Yim. He received a bachelor's degree in Energy and Power Engineering from the School of Energy and Power Engineering at Xi'an Jiaotong University in June 2022. His research focuses on turbomachinery flow physics and mechanism-aware design, combining high-fidelity CFD, experiments, spectral proper orthogonal decomposition, resolvent analysis, pressure-Poisson source analysis and optimization. His work has been published in the Journal of Fluid Mechanics, Physics of Fluids and Ocean Engineering.
Biography: Bingfu Han has been a direct-entry PhD candidate in Energy and Power Engineering at Tsinghua University, Beijing, China, since 2022, under the supervision of Prof. Lei Tan. He is currently a visiting PhD researcher in the HEAD Lab at EPFL from July to October 2026, hosted by Prof. Eunok Yim. He received a bachelor's degree in Energy and Power Engineering from the School of Energy and Power Engineering at Xi'an Jiaotong University in June 2022. His research focuses on turbomachinery flow physics and mechanism-aware design, combining high-fidelity CFD, experiments, spectral proper orthogonal decomposition, resolvent analysis, pressure-Poisson source analysis and optimization. His work has been published in the Journal of Fluid Mechanics, Physics of Fluids and Ocean Engineering.
Practical information
- General public
- Free
Organizer
- MEGA.Seminar Organizing Committee