Vortex criteria can be objectivized by unsteadiness minimization

  title={Vortex criteria can be objectivized by unsteadiness minimization},
  author={Holger Theisel and Markus Hadwiger and Peter Rautek and Thomas Theu{\ss}l and Tobias G{\"u}nther},
  journal={Physics of Fluids},
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… Expand

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