Hydrodynamic Metamaterial Cloak for Drag-Free Flow

Area of Science:

• Fluid dynamics
• Metamaterials science
• Viscous flow manipulation

Background:

• Metamaterials engineered via transformation optics enable control over physical phenomena.
• Existing metamaterials have not been applied to flowing viscous matter.

Purpose of the Study:

• To propose and demonstrate a hydrodynamic metamaterial cloak for concealing objects in 2D creeping flow.
• To guide viscous forces and create a fictitious empty fluidic space.

Main Methods:

• Utilized coordinate transformation of fluidic space to derive a tensoric viscosity.
• Applied form invariance of Navier-Stokes equations for fluidic space transformation.
• Numerically simulated the hydrodynamic cloak with the derived viscosity tensor.

Main Results:

• Verified the creation of a fictitious fluidic empty space within the cloak.
• Designed and fabricated the metamaterial microstructure in a microfluidic device.
• Experimentally demonstrated hydrodynamic hiding of a solid object without flow disturbance or drag.

Conclusions:

• The hydrodynamic metamaterial cloak successfully conceals objects in creeping flow.
• This work extends metamaterial applications to fluid dynamics and viscous matter manipulation.
• The developed cloak offers a novel method for controlling fluidic interactions with solid objects.