Research
Wrinkling and free-surface breakup by elastic sheet retraction
(Main investigator: Cheolgyun Jung)
Elastic membranes filled with fluids, such as water balloons or capsules, are commonly found in our surroundings and are designed to store and transport fluids effectively. These have a wide range of applications in medical and industrial fields, like being used as a drug delivery system using micro-capsules or as an elastic container for energy transportation, and space robots that protect rovers during landing. Thus, it is essential to understand the potential risks that could lead to their rupture. In this study, we examine the relationship between the retraction of an elastic membrane during rupture and accompanying flow phenomena by adopting a simplified model in which an elastic sheet is initially stretched and floats on the free-surface. Both the shear stress acting on the interface and the wrinkling of the elastic sheet during retraction cause the instability of the free surface and directly affect its breakup into ligaments. By analyzing the multi-physics phenomena quantitatively, we elucidate detailed coupling mechanisms between a retracting elastic sheet and the resulting free-surface flow.
Pattern control of elastic structure based on hydrodynamic coupling
(Main investigator: Seyoung Joung)
Regular wrinkle patterns often arise on the surface-level of thin structures when an internal compression is present. Such patterns which are geometrically characterized with certain wavelengths can be controlled by tailoring the mechanical response of the structure and can be utilized in designing surface structure. By coupling the elastic structure with hydrodynamics, an effective way for pattern control under transient loading is accessible based on the temporal control of wrinkling dynamics. Here, we experimentally investigate the dynamics of a wrinkling elastic loop under transient hydrodynamic loading and find the dynamic conditions for emergence of particular modes.
Break-up of a synthetic capsule immersed in shear flow
(Main investigator: Seyoung Joung)
Synthetic capsules wrap some biological or chemical ingredients using a membrane. They are used in diverse industrial and biomedical applications as mediums of mass transport. When a capsule is immersed in an extreme flow environment, high shear stress exerted on the membrane causes severe deformation and structural failure of the capsule. We experimentally and analytically investigate the dynamics of a synthetic capsule in a simple shear flow and elucidate the underlying mechanism of break-up process.
