Effect of Inflow Turbulence on an Airfoil Flow with Laminar Separation Bubble: An LES Study
Publication date
2018
Document type
Research article
Author
Organisational unit
Series or journal
Flow, turbulence and combustion : an international journal published in association with ERCOFTAC
Periodical volume
101
Periodical issue
2
First page
433
Last page
456
Peer-reviewed
✅
Part of the university bibliography
✅
Keyword
Aerodynamic Drag
Atmospheric Boundary Layer
Large eddy simulation (LES)
Abstract
The present paper is concerned with numerical investigations on the effect of inflow turbulence on the flow around a SD7003 airfoil. At a Reynolds number Rec = 60,000, an angle of attack α = 4∘ and a low or zero turbulence intensity of the oncoming flow, the flow past the airfoil is known to be dominated by early separation, subsequent transition and reattachment leading to a laminar separation bubble with a distinctive pressure plateau. The objective of the study is to investigate the effect of inflow turbulence on the flow behavior. For this purpose, a numerical methodology relying on a wall-resolved large-eddy simulation, a synthetic turbulence inflow generator and a specific source term concept for introducing the turbulence fluctuations within the computational domain is used. The numerical technique applied allows the variation of the free-stream turbulence intensity (TI) in a wide range. In order to analyze the influence of TI on the arising instantaneous and time-averaged flow field past the airfoil, the present study evaluates the range 0% ≤ TI ≤ 11.2%, which covers typical values found in atmospheric boundary layers. In accordance with experimental studies it is shown that the laminar separation bubble first shrinks and finally completely vanishes for increasing inflow turbulence. Consequently, the aerodynamic performance in terms of the lift-to-drag ratio increases. Furthermore, the effect of the time and length scales of the isotropic inflow turbulence on the development of the flow field around the airfoil is analyzed and a perceptible influence is found. Within the range of inflow scales studied decreasing scales augment the receptivity of the boundary layer promoting an earlier transition. © 2018, Springer Science+Business Media B.V., part of Springer Nature.
Cite as
In: Flow, turbulence and combustion. - Dordrecht [u.a.] : Springer Science + Business Media B.V., 1947. - Online-Ressource . - Bd. 101.2018, 2, Seite 433-456
Version
Not applicable (or unknown)
Access right on openHSU
Metadata only access