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Hauptverfasser: Cieślak, Tomasz, Kokocki, Piotr, Kosewski, Przemysław
Format: Preprint
Veröffentlicht: 2025
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Online-Zugang:https://arxiv.org/abs/2508.03554
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author Cieślak, Tomasz
Kokocki, Piotr
Kosewski, Przemysław
author_facet Cieślak, Tomasz
Kokocki, Piotr
Kosewski, Przemysław
contents In this paper, we study the problem of uniqueness of a divergence-free velocity field with vorticity given by the Prandtl spiral. We show that if the class of admissible velocities is restricted to those satisfying the velocity matching condition and an appropriate decay condition at the origin of the spiral, then the velocity field is uniquely determined. We subsequently extend the result to the case of fields with vorticity composed of unions of concentric logarithmic spirals. As a by-product, we derive an alternative way of deriving formula for the velocity corresponding to the Prandtl spirals. The proof relies on an approach that is of independent interest. We construct an explicit conformal map from the exterior of a logarithmic spiral onto a strip. This transformation reduces the problem to establishing the uniqueness of a holomorphic function defined on the strip, under non-standard boundary and decay conditions.
format Preprint
id arxiv_https___arxiv_org_abs_2508_03554
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Uniqueness problem for Prandtl spirals
Cieślak, Tomasz
Kokocki, Piotr
Kosewski, Przemysław
Analysis of PDEs
In this paper, we study the problem of uniqueness of a divergence-free velocity field with vorticity given by the Prandtl spiral. We show that if the class of admissible velocities is restricted to those satisfying the velocity matching condition and an appropriate decay condition at the origin of the spiral, then the velocity field is uniquely determined. We subsequently extend the result to the case of fields with vorticity composed of unions of concentric logarithmic spirals. As a by-product, we derive an alternative way of deriving formula for the velocity corresponding to the Prandtl spirals. The proof relies on an approach that is of independent interest. We construct an explicit conformal map from the exterior of a logarithmic spiral onto a strip. This transformation reduces the problem to establishing the uniqueness of a holomorphic function defined on the strip, under non-standard boundary and decay conditions.
title Uniqueness problem for Prandtl spirals
topic Analysis of PDEs
url https://arxiv.org/abs/2508.03554