Network Theoretic Approaches to Modeling Fluid-Structure Interactions
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Authors
Douglass, Samuel B
Issue Date
2023
Type
Thesis
Language
Keywords
Aerodynamics , Computational Fluid Dynamics , Fluid Structure Interaction , Network Science
Alternative Title
Abstract
The coupling interactions between deformable structures and unsteady fluid flows occur across a wide range of spatial and temporal scales in many engineering applications. These fluid-structure interactions (FSI) make it challenging to predict the flow physics accurately. In the present thesis, two multi-layer network approaches are proposed that characterize the interactions between the fluid and structural layers for an incompressible laminar flow over a two-dimensional compliant flat plate at 35-degrees angle of attack. In one approach, the wake vortices and bound vortexlets form the nodes of the network with the edges defined by induced velocity. In the other approach, coherent structures (fluid modes) contributing to the kinetic energy of the flow and structural modes contributing to the kinetic energy of the compliant structure constitute the network nodes. The energy transfers between the modes are extracted using a perturbation approach. The network structure of the FSI system is further simplified using community detection algorithm in the vortical approach and by selecting dominant modes in the modal approach. Network measures are used to reveal the temporal behavior of the individual nodes within the simplified FSI system. A predictive model is then built using a physics-based method. We conclude by investigating controllability of the modal interaction network. This thesis sets the foundation for network-theoretic reduced-order modeling of fluid-structure interactions, generalizable to other multi-physics systems.