An Embedded Boundary Approach for Resolving the Contribution of Cable Subsystems to Fully Coupled Fluid-Structure Interaction

Cable subsystems characterized by long, slender, and flexible structural elements are featured in numerous engineering systems. In each of them, interaction between an individual cable and the surrounding fluid is inevitable. Such a Fluid-Structure Interaction (FSI) has received little attention in the literature, possibly due to the inherent complexity associated with fluid and structural semi-discretizations of disparate spatial dimensions. This paper proposes an embedded boundary approach for filling this gap, where the dynamics of the cable are captured by a standard finite element representation $\mathcal C$ of its centerline, while its geometry is represented by a discrete surface $\Sigma_h$ that is embedded in the fluid mesh. The proposed approach is built on master-slave kinematics between $\mathcal C$ and $\Sigma_h$, a simple algorithm for computing the motion/deformation of $\Sigma_h$ based on the dynamic state of $\mathcal C$, and an energy-conserving method for transferring to $\mathcal C$ the loads computed on $\Sigma_h$. Its effectiveness is demonstrated for two highly nonlinear applications featuring large deformations and/or motions of a cable subsystem and turbulent flows: an aerial refueling model problem, and a challenging supersonic parachute inflation problem. The proposed approach is verified using numerical data, and validated using real flight data.