Testing the Accuracy of the Cell-Set Model Applied on Vane-Type Sub-Boundary Layer Vortex Generators

Koldo Portal-Porras,Iñigo Aramendia,Daniel Teso-Fz-Betoño,Ekaitz Zulueta,Unai Fernandez-Gamiz

doi:10.3390/pr9030503

Koldo Portal-Porras, Iñigo Aramendia + Show 3 more

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https://doi.org/10.3390/pr9030503

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Journal: Processes	Publication Date: Mar 11, 2021
Citations: 10	License type: CC BY 4.0

Affiliation: University of the Basque Country

Abstract

Vortex Generators (VGs) are applied before the expected region of separation of the boundary layer in order to delay or remove the flow separation. Although their height is usually similar to that of the boundary layer, in some applications, lower VGs are used, Sub-Boundary Layer Vortex Generators (SBVGs), since this reduces the drag coefficient. Numerical simulations of sub-boundary layer vane-type vortex generators on a flat plate in a negligible pressure gradient flow were conducted using the fully resolved mesh model and the cell-set model, with the aim on assessing the accuracy of the cell-set model with Reynolds-Averaged Navier-Stokes (RANS) and Large Eddy Simulation (LES) turbulence modelling techniques. The implementation of the cell-set model has supposed savings of the 40% in terms of computational time. The vortexes generated on the wake behind the VG; vortical structure of the primary vortex; and its path, size, strength, and produced wall shear stress have been studied. The results show good agreements between meshing models in the higher VGs, but slight discrepancies on the lower ones. These disparities are more pronounced with LES. Further study of the cell-set model is proposed, since its implementation entails great computational time and resources savings.

Highlights

Vortex Generators (VGs) are passive flow control devices, whose objective is to delay or remove the flow separation, transferring the energy generated from the outer region to the boundary layer region
The meshes generated with the fully mesh model are made of around 11.5 million cells, while the meshes generated with the cell-set model are composed of around 7.2 million cells
The vortex structure regimes on the wake behind the VG; the path, size, and strength of the primary vortex; and the wall shear stress behind it have been studied

Summary

Introduction

Vortex Generators (VGs) are passive flow control devices, whose objective is to delay or remove the flow separation, transferring the energy generated from the outer region to the boundary layer region. They are small vanes placed before the expected region of separation of the boundary layer. They are usually mounted in pairs, with an incident angle with the oncoming flow. Regarding their shape, VGs can be of various geometries, but they are mainly triangular or rectangular.

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