Gayme_ Catalyst Award_2015Dr. Dennice Gayme, Assistant Professor of Mechanical Engineering, was awarded a prestigious and highly competitive 2015 Catalyst Award for her research “extending a wall-turbulence modeling framework to complex fluids.” Dr. Gayme is one of thirty-seven early-career Johns Hopkins faculty members chosen to receive up to $75,000 from the university’s new Catalyst Awards program to catalyze their research and creative endeavors.

This Catalyst Award will enable Dr. Gayme and her students to further develop and extend the restricted nonlinear (RNL) modeling framework for wall-turbulence. This modeling paradigm is based on a multidisciplinary approach to wall-turbulence research, which combines ideas from dynamics and control theory with traditional fluid dynamics tools and methods. Initial results using this approach showed that key nonlinear mechanisms involved in creating the well-known turbulent velocity profile could be illuminated by looking at the problem within a robust control framework. More recent work has shown that the RNL model accurately reproduces flow structures known to play a critical role in the momentum transfer that contributes to the increased shear stress at the wall associated with higher skin-friction drag. The ability of the RNL framework to capture this multiscale process within a simplified model is promising from a flow control development point of view because it means that control strategies designed using this framework may be valid over a wide parameter range.

This research will extend the RNL framework to complex fluids such as viscoelastic flows, i.e., flows with polymer additives. A number of recent studies have drawn connections between turbulence in viscoelastic flows and wall-turbulence, in particular to the self-sustaining process (SSP) that is believed to describe the critical interactions underlying turbulence. Although the basic cycle is generally accepted, the details of the interaction are still widely debated and are even less understood in viscoelastic turbulence. Recent studies into the critical structures involved in the SSP indicate that the RNL framework shows promise in providing new insights into the dynamics that could help resolve some of the open questions. Extensions of the RNL framework to the viscoelastic case will provide a new tool for further investigating the underlying mechanisms of viscoelastic turbulence.

You can read more about the Catalyst Awards here: http://hub.jhu.edu/at-work/2015/06/25/catalyst-award-winners

You can read more about Dr. Gayme’s research here: http://engineering.jhu.edu/gayme/