336 citations · 3.5k across the 72 of their papers we have counts for
13 papers · 1 filter
Exact Model Reduction and Fast Forced Response Calculation in High-Dimensional Nonlinear Mechanical Systems
Sten Ponsioen, George Haller
We show how spectral submanifold (SSM) theory can be used to extract forced-response curves, including isolas, without any numerical simulation in high-degree-of-freedom, periodica…
Confronting Grand Challenges in Environmental Fluid Mechanics
T. Dauxois, T. Peacock, P. Bauer +10
Environmental fluid mechanics underlies a wealth of natural, industrial and, by extension, societal challenges. In the coming decades, as we strive towards a more sustainable plane…
Vortex boundaries as barriers to diffusive vorticity transport in two-dimensional flows
Stergios Katsanoulis, Mohammad Farazmand, Mattia Serra +1
We put forward the idea of defining vortex boundaries in planar flows as closed material barriers to the diffusive transport of vorticity. Such diffusive vortex boundaries minimize…
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…
Search and rescue at sea aided by hidden flow structures
Mattia Serra, Pratik Sathe, Irina Rypina +6
Every year hundreds of people die at sea because of vessel and airplane accidents. A key challenge in reducing the number of these fatalities is to make Search and Rescue (SAR) alg…
Explicit Unsteady Navier-Stokes Solutions and their Analysis via Local Vortex Criteria
Tiemo Pedergnana, David Oettinger, Gabriel Provencher-Langlois +1
We construct a class of spatially polynomial velocity fields that are exact solutions of the planar unsteady Navier-Stokes equation. These solutions can be used as simple benchmark…
How do Conservative Backbone Curves Perturb into Forced Responses? A Melnikov Function Analysis
Mattia Cenedese, George Haller
Weakly damped mechanical systems under small periodic forcing tend to exhibit periodic response in a close vicinity of certain periodic orbits of their conservative limit. Specific…
When does a Periodic Response Exist in a Periodically Forced Multi-Degree-of-Freedom Mechanical System?
Thomas Breunung, George Haller
While periodic responses of periodically forced dissipative nonlinear mechanical systems are commonly observed in experiments and numerics, their existence can rarely be concluded…
Explicit Third-Order Model Reduction Formulas for General Nonlinear Mechanical Systems
Zsolt Veraszto, Sten Ponsioen, George Haller
For general nonlinear mechanical systems, we derive closed-form, reduced-order models up to cubic order based on rigorous invariant manifold results. For conservative systems, the…
Analytic Reconstruction of a Two-Dimensional Velocity Field from an Observed Diffusive Scalar
Arjun Sharma, Irina I. Rypina, Ruth Musgrave +1
Inverting an evolving diffusive scalar field to reconstruct the underlying velocity field is an underdetermined problem. Here we show, however, that for two-dimensional incompressi…
Material spike formation in high Reynolds number flow separation
Mattia Serra, Sean Crouzat, Gael Simon +2
We apply the recent frame-invariant theory of separation spike formation to complex unsteady flows including a turbulent separation bubble, an impinging jet, and flows around a fre…
Barriers to the Transport of Diffusive Scalars in Compressible Flows
George Haller, Daniel Karrasch, Florian Kogelbauer
Our recent work identifies material surfaces in incompressible flows that extremize the transport of an arbitrary, weakly diffusive scalar field relative to neighboring surfaces. S…
Lagrangian coherent structures and entrainment near the turbulent/non-turbulent interface of a gravity current
M. M. Neamtu-Halic, D. Krug, G. Haller +1
In this paper, we employ Lagrangian coherent structures (LCSs) theory for the three dimensional vortex eduction and investigate the effect of large-scale vortical structures on the…