Digital tools to combat rain erosion captures Varanasi Fellowship

PhD student Mira Tipirneni develops computational models to predict and combat aircraft surface damage from rain.

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Ph.D student Mira Tipirneni has been named the 2025 Varanasi Scholar in our department, supporting her innovative research on aircraft coating durability. Her work could transform how aerospace manufacturers test and develop protective coatings for aircraft.

Tipirneni is developing computational models to predict rain erosion on aircraft surfaces—a critical challenge that traditionally requires extensive and costly physical testing. Her research aims to create digital tools that could significantly reduce the industry's reliance on conventional methods like the Whirling Arm test.

"Mira's research is crucial for the future of aerospace engineering," says Professor Antonino Ferrante, her faculty advisor. "By moving away from expensive physical testing towards verified, validated and highly accurate computational models, we are enabling the development of more durable and efficient aircraft."

The Whirling Arm Test, shown here, is the current industry standard for rain erosion testing - but its high costs and time demands drive the need for Tipirneni's computational approach.

At the heart of Tipirneni's work is a novel approach to modeling how water droplets impact aircraft surfaces. She has helped develop a sharp interface method for compressible two-phase flows, advancing beyond traditional diffuse interface methods that struggle to precisely capture the boundary between water droplets and air. This advancement is particularly significant for modeling impacts above Mach 0.3.

Her research is part of a comprehensive approach developed with Boeing that combines material testing, adhesion measurement, and computational fluid dynamics (CFD). Using a Volume of Fluid method, Tipirneni's model has demonstrated remarkable accuracy in resolving flow fields and capturing interfaces in various testing scenarios.

The research, conducted in partnership with Boeing, has important implications for both commercial and military aircraft. By improving the accuracy of rain erosion prediction while reducing development costs, Tipirneni's work could accelerate the introduction of more durable aircraft coatings.

Of the support of this fellowship, Tipirneni says, "I am extremely grateful for this opportunity, which will allow me to focus on the completion of this new solver and its application to study the physics of compressible two-phase flows."

The Varanasi Endowed Fellowship was established by Rao (Ph.D ‘68) and Usha Varanasi (Ph.D. Chemistry ‘68) to help support A&A students with academic merit in our graduate program. The Varanasis are well-known at the UW for their service to our programs. In 2017, they were named UW Laureates. In 2019, Rao was named the A&A Distinguished Alumnus, and in 2022, the College jointly awarded them the Diamond Award for Distinguished Service.