“Numerical Modeling of Flexible Oscillating Water Columns for Wave Energy Conversion”, Proc. EWTEC, vol. 16, Sep. 2025, doi: 10.36688/ewtec-2025-1115.

Abstract:

The Flexible Oscillating Water Column (FlexOWC) introduces an innovative wave energy conversion approach, using a flexible membrane to enhance energy harvesting and system efficiency. This paper presents a numerical investigation of the FlexOWC system integrated within a Coastal Structure Integrated (CSI) framework, advancing renewable energy technologies and coastal resilience. Two complementary numerical modeling techniques assessed the FlexOWC’s
performance. The computationally efficient potential flow model explored geometric and operational configurations across various wave conditions. Simultaneously, a
high-fidelity Computational Fluid Dynamics (CFD) model developed in OpenFOAM captured hydrodynamic interactions and flexible membrane behavior, incorporating
turbulence and fluid-structure interaction models essential for understanding system dynamics. The results show substantial improvements in pneumatic power output compared to traditional rigid Oscillating Water Columns (OWCs). The flexible membrane increased power output under both regular and irregular wave conditions, attributed to its adaptive response to wave forces,
creating favorable pressure distributions in the OWC chamber. These findings demonstrate the potential of flexible membrane technology to optimize energy capture in diverse wave climates. FlexOWC technology offers a scalable and sustainable solution for wave energy conversion, with dual benefits of renewable energy generation and coastal protection against extreme weather events when integrated into multifunctional coastal structures. Future work will focus on experimental validation through prototype testing and field deployment, with industry collaborations ensuring a streamlined path to commercialization and application.

“Experimental Analysis of Flexible Oscillating Water Columns for Wave Energy Conversion”, Proc. EWTEC, vol. 16, Sep. 2025, doi: 10.36688/ewtec-2025-706.

Abstract:

This study presents the results of experimental testing for a Flexible Oscillating Water Column (FlexOWC) system, a new wave energy converter designed to enhance energy capture efficiency. The FlexOWC is being developed at Peak Inc., with funding from the US Department of Energy (DOE) under award DE-SC0025144 [1], and is protected under a US provisional patent for its design and innovative features [2]. The experiments, conducted on a 1:20 scale model in a controlled wave flume environment at the Iowa Institute of Hydraulic Research, Hydroscience and Engineering (IIHR) at the University of Iowa, are compared to numerical simulations under regular wave conditions. Orifices are used to simulate the turbine load. Air compressibility modeling [3] has been accounted for while simultaneously satisfying Froude’s scaling criteria for waves using Air Vessels.

Key findings include demonstrating changes in energy absorption when adding the flexible membrane to the oscillating water column. These experiments demonstrate enhanced energy capture compared to rigid OWC designs. These experiments build on methodologies for resolving wave reflections in experimental setups [5] and validate concepts of pulsating power extraction in OWC systems [6]. The paper will discuss critical insights into the dynamic behavior and scalability of the FlexOWC technology, the system’s adaptability to various wave climates, and the impact of membrane characteristics on pneumatic power, with a description of full-scale prototype implementations.