Overview
My intellectual interests and passions revolve around the desire to understand and predict the beautifully complex, enigmatic motion of turbulent flows, and their role in natural and engineered systems. The environment provides one of the richest settings motivating research on this topic, with far reaching implications for understanding atmospheric clouds, oceans, global warming, among many others. To address the profound complexity of turbulence I utilize methods from applied mathematics, statistical and theoretical physics, and high-performance computing. I also work closely with experimentalists, being convinced that a multifaceted, collaborative approach is required for significant progress on this very challenging subject.
Turbulent flows are inherently multiscale, and in environmental contexts they involve motion on spatial scales ranging from kilometers down to micrometers. Large-scale numerical simulations of environmental flows cannot resolve all of the scales, and so the unresolved scales must be parametrized. However, the nonlinear physics of the unresolved processes are often poorly understood, leading to great uncertainty in their parameterizations. This challenge is a key motivation for my own research, namely to understand the nonlinear physics of these small-scale processes and then to develop models that capture them for use in large-scale numerical models.
Before joining the Duke University faculty, Dr. Bragg was a postdoctoral associate in the Applied Mathematics and Plasma Physics Group at the Los Alamos National Laboratory. Prior to that, he was a postdoctoral associate in the Sibley School of Mechanical and Aerospace Engineering at Cornell University. Dr. Bragg obtained his PhD in Theoretical Fluid Dynamics from Newcastle University in England.
Current Appointments & Affiliations
Recent Publications
Mechanism generating reverse buoyancy flux at the small scales of stably stratified turbulence
Journal Article Journal of Fluid Mechanics · January 5, 2026 Previous studies show that at the small scales of stably stratified turbulence, the scale dependent buoyancy flux reverses sign, corresponding to a conversion of turbulent potential energy (TPE) back into turbulent kinetic energy (TKE). Moreover, the magni ... Full text CiteNon-Stokes deposition velocities observed under Rayleigh–Bénard turbulence
Journal Article Aerosol Science and Technology · January 1, 2026 The settling and deposition behavior of small particles significantly impacts many environmental and industrial processes. Although particle settling dynamics within turbulent environments have been extensively studied through theory and simulation, more e ... Full text CiteLagrangian tracking reveals competing influences of clustering and turbulence on the rise velocity of bubble swarms.
Journal Article Proceedings of the National Academy of Sciences of the United States of America · December 2025 The rise velocity of bubble swarms is a fundamental property in many natural and industrial flows. A central question is whether clustering of bubbles enhances or suppresses their rise velocity compared to isolated single bubbles in quiescent fluid. We add ... Full text CiteRecent Grants
Development and application of a wall model for the dust-laden atmospheric boundary layer
ResearchPrincipal Investigator · Awarded by University of Notre Dame · 2022 - 2026CAREER: Sheared stratified turbulence: novel mechanisms and models of complex wave-vortex interactions that impact our environment
ResearchPrincipal Investigator · Awarded by National Science Foundation · 2021 - 2025Implications of heterogeneity-aware land-atmosphere coupling in the predictability of precipitation extremes
ResearchCo-Principal Investigator · Awarded by National Oceanic and Atmospheric Administration · 2022 - 2024View All Grants