Realizing the multifunctional metamaterial for fluid flow in a porous medium

Abstract

Metamaterials are artificial materials that can achieve unusual properties through unique structures. In particular, their “invisibility” property has attracted enormous attention due to its little or negligible disturbance to the background field that avoids detection. This invisibility feature is not only useful for the optical field, but it is also important for any field manipulation that requires minimum disturbance to the background, such as the flow field manipulation inside the human body. There are several conventional invisible metamaterial designs: a cloak can isolate the influence between the internal and external fields, a concentrator can concentrate the external field to form an intensified internal field, and a rotator can rotate the internal field by a specific angle with respect to the external field. However, a multifunctional invisible device that can continuously tune across all these functions has never been realized due to its challenging requirements on material properties. Inside a porous medium flow, however, we overcome these challenges and realize such a multifunctional metamaterial. Our hydrodynamic device can manipulate both the magnitude and the direction of the internal flow and, at the same time, make negligible disturbance to the external flow. Thus, we integrate the functions of the cloak, concentrator, and rotator within one single hydrodynamic metamaterial, and such metamaterials may find potential applications in biomedical areas such as tissue engineering and drug release.

Hydrodynamic metamaterials: Principles, experiments, and applications

“…Adapted with permission. 82 Copyright 2022, the National Academy of Sciences of the United States of America. PDMS, polydimethylsiloxane.…”

“…This is the first time that such a versatile multifunctional metamaterial has been achieved. 82 As shown in Figure 9a, their system integrates the functions of (1) a cloak that isolates the influence between internal and external fields, (2) a concentrator that concentrates the external field to form an intensified internal field, and (3) a rotator that rotates the field with a broad range of angle. Thus, the system achieves a continuous adjustment in both magnitude and direction of flow with very little disturbance to the background, which are verified by the experiment and simulation data.…”

“…Adapted with permission. 82 Copyright 2022, the National Academy of Sciences of the United States of America. (b) By tuning the pressure of fluid flow people realize a continuous switch from thermal cloaking to thermal concentration in one device.…”

“…(b) One example of a DLP 3D (digital light processing three‐dimensional) printer used to fabricate the multifunctional hydrodynamic metamaterial. Adapted with permission 82 . Copyright 2022, the National Academy of Sciences of the United States of America.…”

Multiple control of thermoelectric dual‐function metamaterials

“…On the other hand, it is important to address the problem that traditional metamaterials only serve single‐target applications. Recently, multifunctional metamaterials 23–28 under the thermoelectric (TE) coupling field have been proposed, which is expected to pave the way for new approaches. However, most of the investigations neglect the regulating effect of the electric field itself on the thermal field.…”