Current interests: Extreme-scale high-fidelity computational simulations of fluid and plasma turbulence

Turbulence in fluids and plasmas plays a critical role in numerous engineering applications and physical phenomena. Extreme-scale high-fidelity simulations of turbulence, carried out over a massive number of computing nodes, provide an unprecedented degree of accuracy and detail. These simulations can be used to gain a greater understanding of turbulence physics and to improve computationally-inexpensive prediciton tools.

As computing power continues to increase, a wider variety of applications will become accessible for analysis thorugh massive-scale simulations. However, further developments in numerical algorithms and high-performance computing are still needed to realize this goal.

Some specific applications of interest include rapidly-distorted turbulence, turbulence in radiation environments, interfacial instabilities and their transition to turbulence, and microturbulence in magnetized plasmas.

PhD Work: Advances in Structure-based Modeling of Turbulent Flows

Structure-based modeling, introduced by Kassinos & Reynolds (1995), argues for the inclusion of additional information in a turbulence model, such as the morphology of structures as described by the dimensionality. We have further developed two structure-based models: the Algebraic Structure-based Model (ASBM) and the Interacting Particle Representation Model (IPRM).

The ASBM is an engineering model of turbulence for wall-bounded turbulent flows. We have formulated a new variant of the model, in which a segregated near-wall correction leads to a new paradigm for model development and comparison. Additionally, a set of fully-explicit equations replace the original formulation and make evident the highly nonlinear nature of the ASBM. Finally a new coupling with transport equations improves the model's accuracy.

The IPRM is a stochastic structure-based model for homogeneous turbulence. We have developed a solution method based on an Eulerian reference frame that replaces the original Lagrangian formulation and thus avoids particle noise. The derivation of the Eulerian formulation, its solution through radial basis functions, and a comparison against the original solution methods have been carried out.