Topical Problems of Fluid Mechanics


Institute of Thermomechanics AS CR, v.v.i.	CTU in Prague Faculty of Mech. Engineering Dept. Tech. Mathematics	MIO Université du Sud Toulon Var - AMU - CNRS - IRD	Czech Pilot centre ERCOFTAC

A Promising Quantitative Measure for Comparison of Power Spectral Densities
Belda M., Isoz M., Měkuta F., Hyhlík T.
Abstract:
The development of temporally resolved simulations and experiments has made the comparison of power spectral densities a growing concern. Assessing the spectra and their similarity is vital for many applications, especially for the validation of temporally resolved simulations. Nowadays, the analysis of spectra in fluid dynamics is usually limited only to assessing whether their slopes fit the theoretical expectations regarding the slope of the inertial region of the turbulence cascade. This approach is used even in cases where no expected slope can be derived. The assessment of similarity is then left to the subjective feeling of ”similar” With the increasing use of high-fidelity results in engineering practice, this approach falls behind. In this contribution, we propose a new method based on the distribution of energy in the spectra to replace the human factor. This method is tested on several spectra that exhibit common properties faced in nowadays problems, such as multiple peaks or inertial region of the turbulence cascade. Presented test results suggest that when combined with classical approaches of fluid mechanics and signal processing, this new method can form the basis for quantitative comparisons of power spectral densities.
Keywords:
Validation methods, PSD, Spectral comparison.

Fulltext: PDF DOI: https://doi.org/10.14311/TPFM.2026.003

In Proceedings Topical Problems of Fluid Mechanics 2026, Prague, 2026, Edited by David Šimurda and Tomáš Bodnár, pp. 17 ISBN 978-80-87012-92-5 (Print) ISSN 2336-5781 (Print)