Key Takeaways
- UCF researchers are studying how wing shape and motion affect the rapid transition of an unmanned aerial vehicle (UAV) from water to air—a process called egress.
- The work, funded by a DEVCOM Army Research Office grant, aims to create mathematical models that improve stability, payload capacity, and autonomous control of amphibious UAVs.
- Understanding egress could enable seamless air‑water operations for military amphibious vehicles, search‑and‑rescue missions, ocean monitoring, and disaster response.
- Experiments use a water tank and 3D‑printed wings to isolate the effects of surface deformation, wave generation, and vortex shedding during egress.
- Preliminary results show lift overshoot followed by a sharp drop, a phenomenon that can destabilize UAVs if not managed.
- The research team, led by Associate Professor Samik Bhattacharya and graduate student Dominic Polidoro, brings strong aerospace‑engineering expertise to the problem.
- Successful models could allow future amphibious UAVs to perform reliable dives and exits in complex environments within the next decade.
Introduction and Significance
The ability of a vehicle to move smoothly between water and air remains a formidable engineering challenge. While nature offers elegant examples—such as a bird bursting from the ocean or a mobula ray launching skyward—replicating this maneuver in unmanned aerial vehicles (UAVs) has proven difficult. UCF Associate Professor Samik Bhattacharya’s research focuses on the split‑second transition known as egress, where a wing exits the water and enters the air. By elucidating the underlying fluid‑dynamic forces, the project seeks to unlock design principles that could make amphibious UAVs far more capable than today’s prototypes.
Research Motivation and Funding
The study is supported by a nine‑month grant from the U.S. Army Combat Capabilities Development Command, known as DEVCOM Army Research Office. This backing reflects the military’s interest in amphibious platforms that can transition without switching vehicles, thereby reducing logistical complexity and increasing operational flexibility. Bhattacharya emphasizes that the technology could “enable seamless air‑water operations without the need for separate vehicles,” a capability that would be valuable not only for defense but also for civilian applications such as coastal search‑and‑rescue, environmental monitoring, and disaster relief.
The Egress Challenge
Although considerable effort has been devoted to understanding how drones enter water, far less is known about the reverse process. Experiments have shown that as a wing rises from the water, lift initially increases, then abruptly reverses direction before stabilizing. This lift overshoot followed by a sharp drop can generate instability, potentially causing loss of control. Bhattacharya notes, “In general, when a UAV egresses, it causes lift overshoot followed by a sharp drop… Such rapid changes in lift forces can create instability.” Pinpointing why this occurs is essential for designing wings that either exploit or mitigate the transient lift changes.
Experimental Approach
To dissect the complex interplay of forces during egress, Bhattacharya and aerospace engineering master’s student Dominic Polidoro use a water tank equipped with 3D‑printed wings inside the Experimental Fluid Mechanics Lab at UCF’s Department of Mechanical and Aerospace Engineering. By varying wing geometry and motion, they can observe how surface deformation, wave generation, and vortex shedding influence the transition. The researcher acknowledges the difficulty: “It’s difficult to disentangle the effects of surface deformation, waves and vortex shedding because they occur simultaneously on very short timescales and strongly influence each other.” High‑speed imaging and force sensors capture data that will later be fed into computational models.
Preliminary Findings
Early results presented at the 2026 American Institute of Aeronautics and Astronautics (AIAA) SciTech Forum revealed the characteristic lift overshoot and subsequent drop during egress. The data suggest that the timing and magnitude of these lift variations are strongly tied to the wing’s shape and the vortices shed from its trailing edge as it breaches the surface. Understanding these relationships is the first step toward devising control strategies—such as adaptive wing morphing or active flow control—that can smooth the transition and maintain stable lift throughout the maneuver.
Potential Applications
If the mathematical models emerging from this work successfully predict and mitigate lift instability, amphibious UAVs could achieve several operational gains. Increased payload capacity would allow them to carry sensors, communication relays, or small cargoes across the air‑water boundary without sacrificing endurance. Autonomous control algorithms could rely on real‑time estimates of egress dynamics to adjust thrust and wing angle, enabling reliable dives and exits even in rough seas or turbulent winds. Beyond the military, civilian agencies could deploy such UAVs for rapid assessment after hurricanes, oil‑spill monitoring, or marine wildlife surveys, where the ability to loiter in the air and then land on water for sampling is invaluable.
Broader Implications
The insights gained from studying egress extend beyond vehicle design. By connecting engineered wing behavior to biological exemplars—birds, flying fish, and rays—the research contributes to a deeper understanding of natural locomotion at fluid interfaces. This cross‑disciplinary perspective may inspire bio‑inspired solutions in other fields, such as underwater robotics or aerial‑water hybrid systems. Moreover, the methodologies developed for isolating simultaneous fluid‑dynamic effects could be adapted to other transient phenomena, like slamming loads on hulls or vortex‑induced vibrations on offshore structures.
Research Team Background
Samik Bhattacharya joined the University of Central Florida in 2016 as an Associate Professor of Aerospace Engineering. He holds a Ph.D. from The Ohio State University, a master’s from Auburn University, and a bachelor’s in mechanical engineering from the National Institute of Technology Warangal, India. His expertise lies in fluid dynamics, aerodynamics, and unsteady flow phenomena. Dominic Polidoro, a master’s student expected to graduate in 2025, brings hands‑on experience with experimental setups and 3D‑printing techniques, contributing significantly to the lab work and data acquisition efforts.
Conclusion and Future Outlook
The ongoing UCF project represents a focused effort to conquer one of the most elusive maneuvers in hybrid vehicle operation: the water‑to‑air transition. By combining targeted experiments, high‑fidelity measurements, and modeling, the team aims to deliver predictive tools that will enable amphibious UAVs to perform stable, reliable egresses under realistic conditions. Should the research succeed, the next decade could witness a new generation of drones capable of seamless air‑water operations, expanding the horizons of both military logistics and civilian emergency response. Continued collaboration with the DEVCOM Army Research Office and potential partnerships with industry will be crucial to transition these laboratory findings into field‑ready technologies.