THERMAL SCIENCE

International Scientific Journal

Lovrenc Novak

,

Tom Bajcar

,

Brane Širok

,

Alen Orbanić

,

Benjamin Bizjan

INVESTIGATION OF VORTEX SHEDDING FROM AN AIRFOIL BY COMPUTATIONAL FLUID DYNAMICS SIMULATION AND COMPUTER-AIDED FLOW VISUALIZATION

ABSTRACT
The article presents an experimental and numerical study of vortex generation and shedding from a NACA 4421 airfoil at low Reynolds number. The experiment was conducted in a low speed wind tunnel by flow visualization. A high speed camera was used to record flow structures at the airfoil trailing edge. The recorded images were processed with an in-house developed software based on the advection-diffusion equation to compute instantaneous 2-D velocity fields. These results were compared with results of the CFD simulation which employed the scale-adaptive simulation (SAS) turbulence modelling. The SST-SAS model produced finer and less stable turbulent structures compared to an URANS simulation with the shear stress transport model. Time averaged velocities and frequency spectra for the both models are in good agreement, but variability of flow in both time and frequency domain is higher in case of the SST-SAS model. Velocity fields computed on the basis of visualization show generally acceptable agreement with the CFD results. Higher errors occur in areas of unperturbed smoke trails and areas of high velocity gradients, however, the vortex shedding frequency is captured with excellent agreement to the experiment.
KEYWORDS
CFD, flow visualization, Airfoil aerodynamics, Vortex street, Scale adaptive simulation
PAPER SUBMITTED: 2017-11-14
PAPER REVISED: 2017-11-25
PAPER ACCEPTED: 2017-11-26
PUBLISHED ONLINE: 2018-02-18
DOI REFERENCE: https://doi.org/10.2298/TSCI170615002N
CITATION EXPORT: view in browser or download as text file
THERMAL SCIENCE YEAR 2018, VOLUME 22, ISSUE Issue 6, PAGES [3023 - 3033]
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Investigation of vortex shedding from an airfoil by computational fluid dynamics simulation and computer-aided flow visualization

© 2024 Society of Thermal Engineers of Serbia. Published by the Vinča Institute of Nuclear Sciences, National Institute of the Republic of Serbia, Belgrade, Serbia. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International licence