Metamaterial-free hydrodynamic cloak design nearly eliminates drag in viscous flows
Metamaterial-free hydrodynamic cloak design nearly eliminates drag in viscous flows lead image
Constructing an object that can travel through a viscous flow at high speeds with near zero drag and lift would be immensely useful in creating more efficient transportation vehicles. However, designing such a material, known as a hydrodynamic cloak, is complicated. Most hydrodynamic cloak designs to date are hard to use in practical applications and often rely on complex metamaterials.
Wang et al. used machine learning to design a spherical, metamaterial-free hydrodynamic cloak that can manipulate the flow field around an object. They employed an optimization algorithm to help identify the optimal distribution of external forces in the cloak design. Numerical software validations showed the cloak reduced drag by more than 96% and allowed the object to not interact with flow fields.
“This represents a significant breakthrough in the field of flow control, allowing objects to move through viscous fluids with no vibration and almost zero drag,” said author Bin Wang. “In addition, the cloak is designed to be activated or deactivated as required, providing a high degree of flexibility.”
The results have potential applications in fields from aerospace to high-speed transportation. Such hydrodynamic cloaks could be used to reduce drag and improve the efficiency of vehicles or navigators. This design in particular could be applied to more practical and high-Reynolds number environments.
“There are still a variety of challenges in the realization of the detailed technology,” Wang said. “We hope that this study can serve as a bridge to establish extensive cooperation with more researchers, so that the related technology can achieve further breakthroughs in the future.”
Source: “Metamaterial-free, zero-drag, spherical hydrodynamic cloaks enabled by machine learning,” by Hao Wang, Bin Wang, Neng-Zhi Yao, Zhengyan Xiao, Chen-Long Wu, Xuesheng Wang, and Xingsheng Wang, Physics of Fluids (2025). The article can be accessed at https://doi.org/10.1063/5.0251301 .
