Researchers at Technion—Israel Institute of Technology, Technische Universität Darmstadt, and IBM Research Europe have recently proposed a new strategy to simultaneously achieve microscale hydrodynamic cloaking and shielding. While the idea of cloaking or shielding objects has been around for some time now, in contrast with other previously developed methods the technique they proposed allows physicists to dynamically switch between these two states.
“When we started with our research, we were aware of work in this direction that is based on porous metamaterials,” Steffen Hardt, who led the research team at TU Darmstadt, told Phys.org. “Our idea was that you do not need such metamaterials if you can inject momentum in a region around the object to be cloaked/shielded. Effectively, this means that you superpose the external flow field by some tailor-made local flow field. As a result, the total flow field (external and local one) comes out such that cloaking or shielding is achieved.”
As part of their previous studies, the researchers developed methods to locally inject momentum using what is known as electroosmotic flow (i.e., motion of liquids typically induced by an applied voltage across a porous material or other fluid conduits). The key objective of their new study was to demonstrate a new method to cloak/shield objects in a fluid flow and make this functionality real-time adaptive, as previously proposed approaches based on metamaterials are not.