Eventos Anais de eventos
COBEM 2017
24th ABCM International Congress of Mechanical Engineering
VELOCITY LEVELS ANALYSIS IN A CROSS FLOW OVER TWO SIDE-BY-SIDE CYLINDERS AND A ROW OF CYLINDERS
Submission Author:
Roberta Fatima Neumeister , DF
Co-Authors:
Sergio Viçosa Möller, Adriane Prisco Petry, Roberta Fatima Neumeister
Presenter: Roberta Fatima Neumeister
doi://10.26678/ABCM.COBEM2017.COB17-0105
Abstract
The present study shows the experimental analysis of cross flow over two cylinders in side-by-side arrangement and a row of cylinders, both cases with P/D = 1.26 and the cylinder diameter is 25mm. The experimental investigation was executed in an aerodynamic channel with Re = 2,2x104 based on the diameter and in the free stream velocity. The velocity signals were acquired with hot-wire anemometry technique and the signal analysis was executed with Fourier Transform, Continuous Wavelet applying db20 and nine levels Discrete Wavelet. The velocity data series were acquired in the gap between the cylinders and in the wakes, to investigate the relations between the signals and the indication of a possible bistable trigger generated by a self-excitation in the gap. The objective also includes investigate the behavior, without bistable flow, in the row case. The results from side-by-side configuration show that there is a level change in the gap flow in the same time that the variation on the wakes happen, but analyzing the energy levels in wavelets results and the Fourier Transform they indicate low energies and low influence in the flow. The results from the row do not present the change in the energy level, but maintain higher energy in the wakes. The non bistable behavior in a row of cylinder might be connected to the low frequencies ranges that predominate in the signals.
Keywords
Turbulent flow, experimental, two side-by-side cylinders, bistability, Row of cylinders
