In a groundbreaking study published in the journal Newton, researchers from the University of Texas at Dallas have challenged a classic physics model that has governed how heat transfers on advanced surfaces for over half a century. The team’s innovative design, aimed at collecting and removing condensates rapidly, yielded surprising results that revealed a significant limitation in the existing theory.

Led by Dr. Xianming (Simon) Dai, associate professor of mechanical engineering, the researchers developed a new theory to explain the phenomenon. Their findings have far-reaching implications for applications such as harvesting water from air without electricity and could lead to more efficient refrigeration systems.

The key to their discovery lies in understanding the behavior of tiny droplets that form on the surface during condensation. Unlike conventional theory, which predicts that these droplets are stationary or slowly moving, the researchers found that they can roll off at high speeds, effectively clearing the surface and making room for more condensates to collect.

The team’s new theory addresses this phenomenon by introducing a concept called “disappearing frequency,” which takes into account the speed at which the surface removes condensates. This approach has allowed them to design surfaces that can efficiently collect and shed these tiny droplets, paving the way for innovative applications.

“We’re excited about the potential of our new theory to help us better design surfaces that condense water or other fluids,” said Dr. Dai, corresponding author of the study. “This could have significant implications for a range of industries, from water harvesting to refrigeration.”

The research was supported by a Defense Advanced Research Projects Agency Young Faculty Award and a National Science Foundation Faculty Early Career Development Program (CAREER) award.

Other co-authors of the paper include Deepak Monga PhD’24, a research scientist in Dr. Dai’s lab; mechanical engineering doctoral student Dylan Boylan; research associate Dhanush Bhamitipadi Suresh MS’21, PhD’24; Jyotirmoy Sarma MS’18, PhD’22; and Dr. Pengtao Wang from Oak Ridge National Laboratory.

The team’s findings have been presented at The American Society of Mechanical Engineers’ 2024 Summer Heat Transfer Conference, where they earned a best presentation award. Their research is expected to be published in an upcoming issue of the journal Newton.

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A team of international scientists, co-led by Nanyang Technological University, Singapore (NTU Singapore), has made a groundbreaking discovery in manipulating water waves. This breakthrough allows them to trap and precisely move floating objects on the surface of the water, effectively demonstrating an invisible force guiding these objects.

The method involves generating and merging water waves to create complex patterns such as twisting loops and swirling vortices. These patterns can pull in nearby floating objects, like small foam balls the size of rice grains, and hold them within the patterns. Some patterns act like tweezers or a “tractor beam” to hold the floating balls in place on the water’s surface so they do not drift away.

Unlike ordinary ripples, these wave patterns remain stable even when disturbed by minor external waves. This technique uses real-world physics to control and shape water waves, but the effect resembles that of an unseen force moving things, as fictionalized in popular shows and books.

The researchers published their findings in the scientific journal Nature on 5 February 2025, opening up new possibilities for using water waves in various applications. For example, the technique could be developed further to corral spilt liquids and chemicals that float on water to make them easier to clean up.

Asst Prof Shen Yijie, one of the co-leads of the research from NTU Singapore’s School of Physical and Mathematical Sciences, and School of Electrical and Electronic Engineering, said, “Our findings are the first step in exploring how water waves can be shaped to move objects, with many potential applications in the future.”

The team plans to work next on establishing whether the water patterns can be created underwater, and not just on the surface, to move submerged objects. They also intend to scale down the water-wave technique to the micrometre level to study if the water patterns on the surface can be used like tweezers to move cells and similarly sized particles precisely.

The technique could also be scaled up to explore whether boats can be guided to a specific location or along a desired path on the water. Researchers would need to factor in disturbances from natural waves at sea that could destroy the water patterns if these sea waves are too strong.

As the water patterns are not easily disrupted, future research could explore the feasibility of using them to store data such as how computers store information. The way water swirls in the patterns is also similar to how light waves and electrons can behave, which suggests that water waves could be studied as a more accessible proxy to research some quantum phenomena seen in light waves and electrons.

An independent and anonymous reviewer of the Nature paper wrote that the study could produce “potential humongous impact…due to its fundamental character” with “a wide range of fields which can benefit from this work.”