How does shark skin inspire the future of aircraft technology? According to Francesco Ambrogi, an Assistant Professor in the Department of Mechanical and Materials Engineering, the correlation is the cornerstone of his research.
“We are studying fluid problems, and the application behind my research was to figure out how a very complex geometry, like the body of a shark swimming or the flow over a wing of an aircraft, behaves under certain flow configurations,” says Ambrogi.
He gives the example of an airplane when it is taking off or landing. The flow configuration over the wings is very particular because the pressure changes both with space and time, generating an unsteady pressure gradient. The same occurs on the epidermis of a shark and many other natural and engineering applications.
He explains how pressure changes along a specific flow direction can cause separation when the flow reverses and moves backward instead of along one direct path. Separation is associated with the failure of many fluid devices and increased drag force. Engineers must try to predict and understand the object's resistance while experiencing this phenomenon.
“The interesting thing about sharks is that they have had millions of years of evolution. If there is something that nature is extremely good at, it is optimizing things to make them work more efficiently. Sometimes we just have to stop and look at nature, learn from it, try to understand why it's gone that way, and design our innovative solutions accordingly,” says Ambrogi.
An expert in fluid mechanics, his work seeks to study sharks' dermal denticles, otherwise known as biomimicry, which is when biological traits are studied to inspire the creation of materials. These structures, very different from fish scales, are ridged and cover a shark's body. They are highly flexible and can easily change orientation with respect to the flow direction. Depending on water flow conditions, these denticles can either lay flat or bristle outwards.
Ambrogi explains that this incredible function and design has the potential to improve aerodynamics and hydrodynamics performance, as well as spawn the creation of innovative mechanical engineering designs, because shark skin allows them to swim more quickly and efficiently, all while reducing drag. Drag is the main factor contributing to an aircraft's fuel consumption. If you can decrease drag, it can amount to big cost savings for companies while providing sustainable solutions in the industry.
In addition to his research, Ambrogi is an award-winning educator at Queen’s. He has received the Bronze Wrench and the Dean’s Teaching Assistant awards, presented to a teaching assistant of Mechanical Engineering for their contribution to the undergraduate class as voted by students and fellow professors, and the Silver Wrench Award for three consecutive years. This prize recognizes a professor who displays the most interest and enthusiasm as chosen by the graduating year. Moreover, he was recognized as a Champion of Mental Health in 2023 due to his innovative teaching methods and philosophy, which he shares are based on three pillars: engagement, inclusion, and feedback.
“We cannot think that a single teaching style will work for everyone. We have huge classes, sometimes 200 plus students, so my philosophy is that I need to be able to accommodate all learning processes,” says Ambrogi. “I try to give them as many resources to learn as I possibly can.”
He shares that some educators he met along his learning journey from high school to graduate studies have left a strong impact and have influenced the way he now teaches due to their inclusive and engaging approach to teaching, something he sincerely admired and appreciated.
“Going through university is not easy. Students are faced with a variety of emotions. They are not just following classes, but they are becoming adults as they go through four to five years of university, so a lot is going on. We are not just teachers. We seek to be mentors for them. From a mental health point of view, we need to be able to generate a healthy learning environment where every student can thrive,” says Ambrogi.
When advising students working toward their career goals, Ambrogi recognizes that there is not one straight path for everyone. He gives the example of how he originally leaned toward studying energy systems but, along the way, began to develop a passion for the physics of fluids and turbulence and shifted course.
“Your dream job today might not even exist five or ten years from now with how fast the world is evolving. The economy is changing, and tools are improving, so don't just fix yourself on one career path you want to achieve; rather, trust where your curiosity lies and feed that curiosity,” says Ambrogi.
“Trust your instincts and be brave to dive in because the beauty of learning and university is that you can make mistakes. You can change your path.”