Vortex Criteria can be Objectivized by Unsteadiness Minimization

Theisel H, Hadwiger M, Rautek P, Theußl T, Günther T (2021)

Publication Language: English

Publication Type: Journal article, Original article

Publication year: 2021

Journal

Physics of Fluids American Institute of Physics (AIP)

DOI: 10.1063/5.0063817

Abstract

Reference frame optimization is a generic framework to calculate a spatially-varying observer field that views an unsteady fluid flow in a reference frame that is as-steady-as-possible. In this paper, we show that the optimized vector field is objective, i.e., it is independent of the initial Euclidean transformation of the observer. To check objectivity, the optimized velocity vectors and the coordinates in which they are defined must both be connected by an Euclidean transformation. In this paper we show that a recent publication applied this definition incorrectly, falsely concluding that reference frame optimizations are not objective. Further, we prove the objectivity of the variational formulation of the reference frame optimization that was recently proposed, and discuss how the variational formulation relates to recent local and global optimization approaches to unsteadiness minimization.

Authors with CRIS profile

Tobias Günther Professur für Visual Computing

Involved external institutions

King Abdullah University of Science and Technology (KAUST) / جامعة الملك عبد الله للعلوم و التقنية SA Saudi Arabia (SA) Otto-von-Guericke-Universität Magdeburg DE Germany (DE)

How to cite

APA:

Theisel, H., Hadwiger, M., Rautek, P., Theußl, T., & Günther, T. (2021). Vortex Criteria can be Objectivized by Unsteadiness Minimization. Physics of Fluids. https://dx.doi.org/10.1063/5.0063817

MLA:

Theisel, Holger, et al. "Vortex Criteria can be Objectivized by Unsteadiness Minimization." Physics of Fluids (2021).

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