Fluid-structure interactions of hyperelastic geomembranes in pressure flow

In the context of decarbonization and energy transition, hydropower is poised to have a major importance in the coming decades. Though, nearly half of hydropower plants were commissioned worldwide before the 1980s and are now approaching a critical stage of aging, causing new challenges and reducing their operational capacity. Hydropower therefore requires the development of reliable, innovative solutions for maintenance and rehabilitation that guarantee both safety and optimized operations. Geomembrane systems are a promising technology to reduce water and energy losses, thus increasing the flexibility and efficiency of existing schemes.

In hydropower waterways, which tend to experience a reduction of their efficiency with time, increasing energy losses, geomembrane systems usually consist of an exposed hyperelastic geomembrane applied to the existing lining and in contact with the water, in addition to anchor elements. Geomembranes are usually manufactured from polymeric materials, which exhibit nonlinear mechanical behavior. This type of application presents numerous challenges, due to extreme flow conditions related to hydropower operations. The flow is typically pressurized. Fluid-structure interactions are therefore paramount for hyperelastic geomembranes used for the rehabilitation of hydraulic structures. Previous studies have shown that the physical mechanisms that lead to flow-induced deformations and vibrations are complex and must be accounted for in the design of flexible structures. This research project aims at assessing fluid-structure interactions of hyperelastic geomembranes in hydropower waterways by means of experimental and numerical modeling. The objectives are to characterize the dynamic response of hyperelastic geomembranes, including flow-induced deformations, flow-induced vibrations, and the subsequent impacts on flow features.