scholarly journals Separated Flow Response to Rapid Flap Deflection

AIAA Journal ◽  
2020 ◽  
Vol 58 (4) ◽  
pp. 1446-1457
Author(s):  
Albert Medina ◽  
Maziar S. Hemati ◽  
Matthew Rockwood
Keyword(s):  
Separated Flow ◽  
Flow Response ◽  
Flap Deflection

scholarly journals Numerical analysis of high-lift configurations with oscillating flaps

2021 ◽  
Author(s):  
Johannes Ruhland ◽  
Christian Breitsamter
Keyword(s):  
Reynolds Number ◽  
Flow Separation ◽  
Separated Flow ◽  
Navier Stokes ◽  
Rotational Axis ◽  
High Lift ◽  
Hinge Point ◽  
Reduced Frequency ◽  
Flap Deflection ◽  
The Impact

AbstractThis study presents two-dimensional aerodynamic investigations of various high-lift configuration settings concerning the deflection angles of droop nose, spoiler and flap in the context of enhancing the high-lift performance by dynamic flap movement. The investigations highlight the impact of a periodically oscillating trailing edge flap on lift, drag and flow separation of the high-lift configuration by numerical simulations. The computations are conducted with regard to the variation of the parameters reduced frequency and the position of the rotational axis. The numerical flow simulations are conducted on a block-structured grid using Reynolds Averaged Navier Stokes simulations employing the shear stress transport $$k-\omega $$ k - ω turbulence model. The feature Dynamic Mesh Motion implements the motion of the oscillating flap. Regarding low-speed wind tunnel testing for a Reynolds number of $$0.5 \times 10^{6}$$ 0.5 × 10 6 the flap movement around a dropped hinge point, which is located outside the flap, offers benefits with regard to additional lift and delayed flow separation at the flap compared to a flap movement around a hinge point, which is located at 15 % of the flap chord length. Flow separation can be suppressed beyond the maximum static flap deflection angle. By means of an oscillating flap around the dropped hinge point, it is possible to reattach a separated flow at the flap and to keep it attached further on. For a Reynolds number of $$20 \times 10^6$$ 20 × 10 6 , reflecting full scale flight conditions, additional lift is generated for both rotational axis positions.

An Investigation of Flow Fields Over Multi-Element Aerofoils

2001 ◽  
Vol 124 (1) ◽  
pp. 154-165 ◽  
Author(s):  
S. R. Maddah ◽  
H. H. Bruun
Keyword(s):  
Flow Field ◽  
Computational Study ◽  
Separated Flow ◽  
Mean Flow ◽  
Model Configuration ◽  
Attached Flow ◽  
The Mean ◽  
Flap Deflection ◽  
Comparative Results ◽  
Lift And Drag

This paper presents results obtained from a combined experimental and computational study of the flow field over a multi-element aerofoil with and without an advanced slat. Detailed measurements of the mean flow and turbulent quantities over a multi-element aerofoil model in a wind tunnel have been carried out using stationary and flying hot-wire (FHW) probes. The model configuration which spans the test section 600mm×600mm, is made of three parts: 1) an advanced (heel-less) slat, 2) a NACA 4412 main aerofoil and 3) a NACA 4415 flap. The chord lengths of the elements were 38, 250 and 83 mm, respectively. The results were obtained at a chord Reynolds number of 3×105 and a free Mach number of less than 0.1. The variations in the flow field are explained with reference to three distinct flow field regimes: attached flow, intermittent separated flow, and separated flow. Initial comparative results are presented for the single main aerofoil and the main aerofoil with a nondeflected flap at angles of attacks of 5, 10, and 15 deg. This is followed by the results for the three-element aerofoil with emphasis on the slat performance at angles of attack α=10, 15, 20, and 25 deg. Results are discussed both for a nondeflected flap δf=0deg and a deflected flap δf=25deg. The measurements presented are combined with other related aerofoil measurements to explain the main interaction of the slat/main aerofoil and main aerofoil/flap both for nondeflected and deflected flap conditions. These results are linked to numerically calculated variations in lift and drag coefficients with angle of attack and flap deflection angle.

Some Aspects of the Aerodynamics of Gurney Flaps on a Double-Element Wing

2000 ◽  
Vol 123 (1) ◽  
pp. 99-104 ◽  
Author(s):  
David Jeffrey ◽  
Xin Zhang ◽  
David W. Hurst
Keyword(s):  
Laser Doppler Anemometry ◽  
Separated Flow ◽  
Surface Flow ◽  
Wake Flow ◽  
Single Element ◽  
Suction Surface ◽  
Gurney Flaps ◽  
Gurney Flap ◽  
Flow Features ◽  
Flap Deflection

Gurney flaps of different heights have been fitted to a generic double-element wing, and the effects at two typical flap angles have been observed using force and pressure measurements, and by performing flow surveys using Laser Doppler Anemometry. At a low flap setting angle of 20 deg the suction-surface flow remains attached to the trailing edge of the flap, and vortex flow features and perturbation velocities are all similar to those observed when Gurney flaps are fitted to single element wings. At a high flap deflection of 50 deg there is an extensive region of separated flow over the flap, yet the Gurney flap still alters the flow structure. The measurements suggest that the wake flow behind the Gurney flap consists of a von Karman vortex street of alternately shed vortices. The effects of the Gurney flap on the lift, zero-lift drag, and pressure distributions are reported, and the differences between the trends observed for single-element wings are discussed.

Separated Flow Response to Single Pulse Actuation

AIAA Journal ◽  
2015 ◽  
Vol 53 (1) ◽  
pp. 190-199 ◽  
Author(s):  
Thomas Albrecht ◽  
Tom Weier ◽  
G. Gerbeth ◽  
Bruno Monnier ◽  
David R. Williams
Keyword(s):  
Separated Flow ◽  
Single Pulse ◽  
Flow Response

Comparison of a Separated Flow Response to Localized and Global-type Disturbances

2015 ◽  
Author(s):  
Bruno Monnier ◽  
David R. Williams ◽  
Tom Weier ◽  
Thomas Albrecht
Keyword(s):  
Separated Flow ◽  
Flow Response ◽  
Global Type

Comparison of a separated flow response to localized and global-type disturbances

2016 ◽  
Vol 57 (7) ◽  
Author(s):  
Bruno Monnier ◽  
David R. Williams ◽  
Tom Weier ◽  
Thomas Albrecht
Keyword(s):  
Separated Flow ◽  
Flow Response ◽  
Global Type
Sign in / Sign up

Export Citation Format

Share Document