By Edwin B Smith
University of Mississippi
Sharks have a built-in drag-reducing system in the scales that line their bodies. A University of Mississippi mechanical engineer is trying to use the same approach to make airplanes run faster and use less fuel, help pipelines pump more oil with less effort, and even help doctors treat chronic lung disease.
Wen Wu, an assistant professor at the School of Engineering, is a principal investigator on a project that involves observing and analyzing moving shark scales and then adapting the results to practical, real-world applications. Wu’s research was recognized with a two-year grant of $173,392 from the National Science Foundation’s established Track-4 program to stimulate competitive research.
EPSCoR is a national platform for funding the projects of researchers whose research advances education and technology, particularly in underrepresented regions.
“This research addresses a long-standing issue in the fluid community; that reduces drag,” Wu said. “We want to run/swim faster. We try to design planes/ships/rockets that use less fuel and travel as fast as possible.
“We hope to be able to pump the crude oil through pipelines with minimal pumping power to reduce transportation costs.”
For decades, scientists and engineers have tried various approaches to reduce drag in fluid flows. A limitation of current methods is that each of them is designed to account for specific flows. If the actual function deviates from this design, it can lead to deterioration – such as increased drag – rather than a reduction in drag.
Shark scales have a unique property that current techniques overlook, Wu said. The scales reduce drag by using different bristle angles in different flow conditions. These bristle angle adjustments require no energy input from the shark.
“It appears to be flow-activated,” he said. “It’s a promising feature that, if properly understood and harnessed, can greatly improve the performance and robustness of drag reduction techniques.”
NSF EPSCoR Track 4 grants support young faculty to develop expertise that needs to help expand their future research areas.
“In this collaboration, I will be supported by Dr. Parviz Moin, the world’s leading scientist in turbulence physics and modeling, at the Center for Turbulence Research in Stanford,” Wu said. “I will learn how to simulate the interaction between a moving surface structure and the flow and how to develop models to represent this interaction in the design process.”
Wu believes that research in the state and region can help develop new manufacturing capabilities in the long term. Possible products that could emerge from his work could be things like adjustable, low-drag surfaces for ships and airplanes, noise-reducing rotor blades or wind turbines, and biomedical technologies that help treat chronic obstructive pulmonary diseases.
Wu will also work with engineers in forest-related industries to understand how the interaction between airflow and plant life affects sprinkler systems, wind erosion control and pesticide application. All of these applications could make forestry more profitable.
Wu’s latest research achievement continues a success story he began before joining Ole Miss’ mechanical engineering department in February 2020.
“DR. Wu’s professional achievements include a series of fruitful investigations into flow separation from its adjacent surface,” said Arunachalam Rajendran, UM Chair and Professor of Mechanical Engineering.
“I think his work offers great insights into our currently insufficient knowledge of turbulent flows from many perspectives. These flows are among the most critical factors affecting thermal fluid device performance and are the most difficult for numerical tools to accurately predict.
“DR. Wu’s research will develop better computer modeling tools that could improve future design processes.”