22 citations · 62 across the 9 of their papers we have counts for
9 papers
Turbulent Snow Transport and Accumulation: New Reduced-Order Models and Diagnostics
Nikolas O. Aksamit, Alex P. Encinas-Bartos, Holt Hancock +1
Understanding and modeling snow particle dynamics in the atmosphere remains a significant challenge for atmospheric scientists, hydrologists, and glaciologists. Temporally and spat…
Relative Fluid Stretching and Rotation for Sparse Trajectory Observations
Nikolas O. Aksamit, Alex P. Encinas-Bartos, George Haller +1
As most mathematically justifiable Lagrangian coherent structure detection methods rely on spatial derivatives, their applicability to sparse trajectory data has been limited. For…
Interplay between advective, diffusive, and active barriers in Rayleigh-Bénard flow
Nikolas Aksamit, Robert Hartmann, Detlef Lohse +1
Our understanding of the material organization of complex fluid flows has recently benefited from mathematical developments in the theory of objective coherent structures. These me…
Quasi-Objective Eddy Visualization from Sparse Drifter Data
Alex P. Encinas Bartos, Nikolas O. Aksamit, George Haller
We employ a recently developed single-trajectory Lagrangian diagnostic tool, the trajectory rotation average , to visualize oceanic vortices (or eddies…
Objective Momentum Barriers in Wall Turbulence
Nikolas O. Aksamit, George Haller
We use the recent frame-indifferent theory of diffusive momentum transport to identify internal barriers in wall-bounded turbulence. Formed by the invariant manifolds of the Laplac…
Quasi-Objective Coherent Structure Diagnostics from Single Trajectories
George Haller, Nikolas Aksamit, Alex P. Encinas Bartos
We derive measures of local material stretching and rotation that are computable from individual trajectories without reliance on other trajectories or on an underlying velocity fi…
Machine-Learning Ocean Dynamics from Lagrangian Drifter Trajectories
Nikolas O. Aksamit, Themistoklis P. Sapsis, George Haller
Lagrangian ocean drifters provide highly accurate approximations of ocean surface currents but are sparsely located across the globe. As drifters passively follow ocean currents, t…
Some Technical Thoughts on Modeling
Nikolas O. Aksamit, Don H. Tucker, James F. Tucker
This paper is more an essay than a report. There is a gentle introduction to some issues in modeling, followed by the use of steepest descent methods to develop a model as contrast…
Eye of the Beholder
Nikolas Aksamit, Don Tucker
We show that the real line R viewed as a vector space is of uncountable (algebraic) dimension over the scalar field Q of rational numbers. We then build an operator J which maps {R…