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A classic textbook example of failure of large engineering structure is the Tacoma Narrows bridge disaster of 1940. An ultimate failure was related to self-excitation and resonance. The accident led researchers to rethink about the design approach. Although the present project has wide scope in mechanical engineering, the proposed research focuses on hydraulic turbines. Need for energy flexibility and interconnection with wind/solar energy have pushed hydro turbomachines to the limit. Turbines are subject to heavy resonance and forced excitation, which often results in ultimate (premature) failure. Then, the question is how to minimize the damage. Insofar, damping is determined a generic approach, engineering linear relation, based on damped natural frequency. However, boundary layer has essential role to create damping effect. For instance, when a structure reverberates, it dissipates kinetic energy to the fluid through boundary layer, i.e., fluid structure interface, and vice versa. This project aims to determine the damping effect that accounts boundary layer complexities. The project will carry out experimental and numerical investigations of boundary layer at a level of multi physics. Pressure, strain and velocity (PIV) measurements will be conducted on a turbine blade. The project aims to quantify the flow instability, mainly kinetic energy fluctuations, inside the boundary layer, and the role of fluid added damping. Three different test cases will be investigated: (1) radial blade cascade, (2) rotating disc and (3) planar flow on reverberating longitudinal plate.
Project team
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Chirag Trivedi leads the Fluid Structure Interaction Research Group, based in the Waterpower Laboratory. He joined the Waterpower Laboratory in April 2012 as an exchange doctoral researcher, then as a Postdoctoral Fellow in August 2014, and later as an Associate Professor in July 2020. With over 15 years of experience in Francis turbines and reversible pump-turbines, Chirag coordinates the group’s activities and supervises students. He is actively involved in both numerical and experimental research, as well as in developing the test rig for the project. |
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Gabriele Gaiti is is a PhD candidate who joined the research group in August 2021. He conducts fundamental research on fluid-structure interactions, focusing on hydrodynamic damping on hydrofoils. Gabriele has developed a radial blade cascade for damping and vibration measurements, enabling the measurement of pressure, velocity, and strain in hydrofoil test sections. Additionally, he is conducting numerical simulations of one-way fluid-structure interactions on hydrofoils. |
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Dadi Ram Dahal is a PhD candidate who joined the research group in September 2022. He conducts fundamental research on fluid-structure interactions, with a focus on the boundary layer on resonating surfaces. Dadi has developed test rigs for boundary layer research, enabling the measurement of pressure, velocity, and strain in hydrofoil test sections. Additionally, he is conducting numerical simulations of one-way and two-way fluid-structure interactions on geometrical shapes such as circular discs and rectangular plates. |
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Jørgen Heggeseth Bakkeng writes master's thesis during spring 2025. The title of the thesis is "Study performance characteristics of benchmark test rig at different Reynolds number". Jørgen will carry out the experiments on the test rig designed for planar flow at different Reynolds numbers, including calibration of the important instruments equipped on the test rig. Main task is to determine the performance of the rig and create benchmark measurement data. This data will help to understand the rig characteristics during the FSI measurements with PIV and boundary layer. |
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Test rig: Radial blade cascade
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Calibration of the pressure and temperature sensors is concluded. The rig is being prepared for the measurements.
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