by

Assistant Professor

IIHR - Hyrdroscience and Engineering

University of Iowa

Fluid-structure interactions (FSI) can drive radical changes in the response behavior and stability of immersed structures, with outcomes ranging from the catastrophic structural failure of civil structures to the beneficial delay of stalled flow in high-lift aerospace control surfaces. Despite the ubiquity and importance of FSI in marine settings, direct observation of compliant structures is difficult to achieve. This talk will describe recent advances in the sensor design and modeling methodologies being used to study complex fluid-structure interaction problems. A robust, low-cost kinematic shape sensor (KSS) has been designed, built, and tested, which offers 3D shape reconstruction with precision on par with photogrammetric methods, but without the need for optical access. When paired with robust parameter estimation algorithms, such as stochastic subspace ID, the KSS affords extremely accurate resolution of mode shapes and modal parameters for structures excited by ambient flow conditions. A co-analysis framework is introduced, wherein output-only structural analysis is executed concurrently with spectral proper orthogonal decomposition of a secondary videographic dataset, providing insight into synchronous fluid modes accompanying or exciting structural vibration. This FSI co-analysis is used to demonstrate modal coalescence, cavitation-induced vibration, and vortex lock-in of a compliant lifting surface in multi-phase flow.

Casey Harwood is an Assistant Professor in Mechanical Engineering and an Assistant Research Engineer with IIHR – Hydroscience and Engineering. Dr. Harwood received his M.S.E. and Ph.D in Naval Architecture and Marine Engineering from the University of Michigan and his B.S. also in Naval Architecture and Marine Engineering, from the Webb Institute in New York. At the University of Iowa, Dr. Harwood leads the Marine Science and Technology (MaST) lab, which performs research in experimental marine hydrodynamics. His current areas of focus include fluid-structure interactions, model-scale testing of marine vehicles, and surf-zone hydrodynamics.