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COBEM 2019
25th International Congress of Mechanical Engineering
HILBERT-HUANG TRANSFORM APPLYED WITH DETERMINISTIC PERTURBATION AND WHITE NOISE ON WAKE SIGNALS FROM CYLINDER WITH TRIPWIRE
Submission Author:
Ana Ost , RS , Brazil
Co-Authors:
Ana Ost, Roberta Fatima Neumeister, Sergio Viçosa Möller
Presenter: Ana Ost
doi://10.26678/ABCM.COBEM2019.COB2019-0713
Abstract
This study provides an evaluation of the performance of Hilbert-Huang Transform as a tool of analysis for turbulent flows. The method was applied in the analysis of the turbulent wake flow past a single circular cylinder with and without trip wire. The study was conducted in an aerodynamic channel with a 25 mm cylinder located in the test section and Reynolds number of 2.7x104, based on the diameter and free stream velocity of the undisturbed flow. The trip wires present 2.3 mm diameter, representing 9% of cylinder diameter, and were positioned at ±45° from the stagnation point. The velocity was obtained with constant temperature anemometer. A deterministic periodic function, of constant amplitude and frequency was added in the velocity signal with the purpose evaluate the flow scale separation of the short period oscillations, and prevent mixing mode from happening. HHT was assisted by Fourier Transform and Wavelet Transform. Results showed that HHT satisfactory separated the short period perturbation and that the addition of the perturbation contributed to avoid mode mixing in the small flow scales.
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