# Engineering Mechanics

Proceedings Vol. 32 (2026)

ENGINEERING MECHANICS 2026

Copyright © 2026 Institute of Thermomechanics of the Czech Academy of Sciences, Prague

 

Smyk E.
pages 117 - 120, full text

The purpose of this study is to verify whether calculating total entropy generation can serve as a method for evaluating flow quality when the velocity profile is determined using theoretical formulas, such as Prandtl's power law. Current methods for assessing flow straighteners rely mainly on qualitative analysis of the velocity profile shape, which impedes objective comparisons. The investigation involved calculations for a pipe with a diameter of 100 mm at a Reynolds number of 10,000, analysing power-law exponents n ranging from 5 to 12 as well as laminar flow. The results indicate that specific generated entropy increases with the exponent n, implying that a more turbulent profile generates higher entropy. Although the total entropy for n=5 was found to be lower than for laminar flow, literature suggests such low exponents are practically impossible in real-world scenarios. This confirms that the assumption of using generated entropy to evaluate flow conditioning is valid for practical applications.

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