The SOFIA Laboratory is part of the Mechanical & Aerospace Engineering Department at the University of California, Los Angeles, and is directed by Professor Jeff D. Eldredge. We are interested in exploring a wide variety of phenomena that occur in fluid flows in nature and technology. The members of our group are investigating...

• The fluid dynamics of biological and biologically-inspired locomotion.
• Numerical simulations of transitional and turbulent hypersonic boundary layer flows.
• Novel techniques for aerodynamic control in next-generation aircraft.
• New computational tools for simulation of cardiovascular flows.
• Fundamental processes of sound generation in jet exhausts.
• Strategies for control of an unstable gas turbine combustor for cleaner and more efficient energy conversion.

Though these topics are superficially diverse, they have an essential unifying principle: they are all unsteady flow phenomena. For example, a flying insect generates lift and thrust by the unsteady production of vorticity—the local rotation of the fluid—at the edges of its wings. An insect has an amazing mastery of its medium that we are only beginning to understand. By concentrating on the tools that natural selection has endowed, then perhaps we can develop new ideas for controlling aircraft!

In order to construct a new generation of space exploration vehicles that are reusable and cost-efficient, we need a much better understanding of the aerodynamics of the vehicle during re-entry into our atmosphere (or entry into another planet's). These vehicles travel at several times the speed of sound during re-entry. Consequently, the transition of the boundary layer from laminar to turbulent can have dire repercussions on the health of the vehicle, due to the large increase in localized heating. We are developing more accurate tools to predict this transition.

Sound is also an unsteady process—often, an undesirable one—and we are interested in how it is produced (and just as importantly, ways it can be removed) by fluid flows. The exhaust of a jet engine is a highly turbulent flow that is a major culprit in the noise produced by an airplane. By examining the fundamental mechanisms that are responsible for this sound, then we may find new opportunities for making it less of a nuisance. Sound is also responsible for creating large, potentially damaging oscillations in industrial gas turbines because of their coupling with combustion. We are developing innovative ideas to remove acoustic energy from these systems, so that they can operate in the cleanest, most efficient mode possible.

In most of these projects, we primarily rely on computational simulation to provide answers to our questions. However, it is essential to complement this with physical investigations, and for this we build simple proof-of-concept experiments or collaborate with other research groups.