The Footprint of Laminar Separation on a Wall-Bounded Wing Section at Transitional Reynolds Numbers

Fuente: arXiv
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Main Authors: Klewicki, Charles, Klose, Bjoern F., Jacobs, Gustaaf B., Spedding, Geoffrey R.
Format: Preprint
Published: 2024
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_version_ 1866910913781563392
author Klewicki, Charles
Klose, Bjoern F.
Jacobs, Gustaaf B.
Spedding, Geoffrey R.
author_facet Klewicki, Charles
Klose, Bjoern F.
Jacobs, Gustaaf B.
Spedding, Geoffrey R.
contents When a chordwise Reynolds number (Re) falls below about $10^5$ the performance of wings and aerodynamic sections become sensitive to viscous phenomena, including boundary layer separation and possible reattachment. Here, detailed measurements of the flow inside the boundary layer on the suction surface are shown for an aspect ratio 3 wing with wall boundaries. The separation lines and recirculation zones are shown on the wing and on the wall junction as Re and angle of incidence, ($α$) are varied. There is good agreement on the lowest Re case which has also been computed in direct numerical simulation. Though the flow at midspan may sometimes be described as two-dimensional, at $α\leq 6^\circ$ it is unrepresentative of the remainder of the wing, and the influence of the wall is seen in strong spanwise flows aft of the separation line. The geometry of the NACA 65(1)-412 section, used here, promotes a substantial chord length for the development of the recirculating regions behind separation making it apt for their study. However, the phenomena themselves are likely to be found over a wide range of wings with moderate thickness at moderate $α$.
format Preprint
id arxiv_https___arxiv_org_abs_2411_05926
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle The Footprint of Laminar Separation on a Wall-Bounded Wing Section at Transitional Reynolds Numbers
Klewicki, Charles
Klose, Bjoern F.
Jacobs, Gustaaf B.
Spedding, Geoffrey R.
Fluid Dynamics
When a chordwise Reynolds number (Re) falls below about $10^5$ the performance of wings and aerodynamic sections become sensitive to viscous phenomena, including boundary layer separation and possible reattachment. Here, detailed measurements of the flow inside the boundary layer on the suction surface are shown for an aspect ratio 3 wing with wall boundaries. The separation lines and recirculation zones are shown on the wing and on the wall junction as Re and angle of incidence, ($α$) are varied. There is good agreement on the lowest Re case which has also been computed in direct numerical simulation. Though the flow at midspan may sometimes be described as two-dimensional, at $α\leq 6^\circ$ it is unrepresentative of the remainder of the wing, and the influence of the wall is seen in strong spanwise flows aft of the separation line. The geometry of the NACA 65(1)-412 section, used here, promotes a substantial chord length for the development of the recirculating regions behind separation making it apt for their study. However, the phenomena themselves are likely to be found over a wide range of wings with moderate thickness at moderate $α$.
title The Footprint of Laminar Separation on a Wall-Bounded Wing Section at Transitional Reynolds Numbers
topic Fluid Dynamics
url https://arxiv.org/abs/2411.05926