Flap upward deflection and rearward bump combination to alleviate transonic buffet of supercritical wing

2018 ◽  
Author(s):  
Gao Shiqi ◽  
Yun Tian ◽  
Peiqing Liu ◽  
Qiulin Qu
Keyword(s):  
Upward Deflection ◽  
Transonic Buffet

Spoiler Upward Deflection on Transonic Buffet Control of Supercritical Airfoil and Wing

2017 ◽  
Vol 54 (3) ◽  
pp. 1229-1233 ◽  
Author(s):  
Yun Tian ◽  
Peihua Feng ◽  
Peiqing Liu ◽  
Tianxiang Hu ◽  
Qiulin Qu
Keyword(s):  
Supercritical Airfoil ◽  
Upward Deflection ◽  
Transonic Buffet

scholarly journals Transonic buffet instability: From two-dimensional airfoils to three-dimensional swept wings

2019 ◽  
Vol 4 (10) ◽  
Author(s):  
Edorado Paladini ◽  
Samir Beneddine ◽  
Julien Dandois ◽  
Denis Sipp ◽  
Jean-Christophe Robinet
Keyword(s):  
Three Dimensional ◽  
Two Dimensional ◽  
Swept Wings ◽  
Transonic Buffet

scholarly journals Analysis of transonic buffet using dynamic mode decomposition

2021 ◽  
Vol 62 (4) ◽  
Author(s):  
Antje Feldhusen-Hoffmann ◽  
Christian Lagemann ◽  
Simon Loosen ◽  
Pascal Meysonnat ◽  
Michael Klaas ◽  
...  
Keyword(s):  
Shock Wave ◽  
Flow Field ◽  
Acoustic Waves ◽  
Feedback Loop ◽  
Measurement Data ◽  
Dynamic Mode Decomposition ◽  
Recirculation Region ◽  
Dynamic Mode ◽  
Mode Decomposition ◽  
Transonic Buffet

AbstractThe buffet flow field around supercritical airfoils is dominated by self-sustained shock wave oscillations on the suction side of the wing. Theories assume that this unsteadiness is driven by a feedback loop of disturbances in the flow field downstream of the shock wave whose upstream propagating part is generated by acoustic waves. High-speed particle-image velocimetry measurements are performed to investigate this feedback loop in transonic buffet flow over a supercritical DRA 2303 airfoil. The freestream Mach number is $$M_{\infty } = 0.73$$ M ∞ = 0.73 , the angle of attack is $$\alpha = 3.5^{\circ }$$ α = 3 . 5 ∘ , and the chord-based Reynolds number is $${\mathrm{Re}}_{c} = 1.9\times 10^6$$ Re c = 1.9 × 10 6 . The obtained velocity fields are processed by sparsity-promoting dynamic mode decomposition to identify the dominant dynamic features contributing strongest to the buffet flow field. Two pronounced dynamic modes are found which confirm the presence of two main features of the proposed feedback loop. One mode is related to the shock wave oscillation frequency and its shape includes the movement of the shock wave and the coupled pulsation of the recirculation region downstream of the shock wave. The other pronounced mode represents the disturbances which form the downstream propagating part of the proposed feedback loop. The frequency of this mode corresponds to the frequency of the acoustic waves which are generated by these downstream traveling disturbances and which form the upstream propagating part of the proposed feedback loop. In this study, the post-processing, i.e., the DMD, is highlighted to substantiate the existence of this vortex mode. It is this vortex mode that via the Lamb vector excites the shock oscillations. The measurement data based DMD results confirm numerical findings, i.e., the dominant buffet and vortex modes are in good agreement with the feedback loop suggested by Lee. Graphic abstract

Simulation of Transonic Buffet Using a Time-Spectral Method

AIAA Journal ◽  
2019 ◽  
Vol 57 (3) ◽  
pp. 1275-1287 ◽  
Author(s):  
Frédéric Plante ◽  
Éric Laurendeau
Keyword(s):  
Spectral Method ◽  
Time Spectral Method ◽  
Transonic Buffet

Upper Trailing-Edge Flap for Transonic Buffet Control

2018 ◽  
Vol 55 (1) ◽  
pp. 382-389 ◽  
Author(s):  
Y. Tian ◽  
Z. Li ◽  
P. Q. Liu
Keyword(s):  
Trailing Edge ◽  
Trailing Edge Flap ◽  
Transonic Buffet

scholarly journals Factors Controlling Rain on Small Tropical Islands: Diurnal Cycle, Large-Scale Wind Speed, and Topography

2017 ◽  
Vol 74 (11) ◽  
pp. 3515-3532 ◽  
Author(s):  
Shuguang Wang ◽  
Adam H. Sobel
Keyword(s):  
Wind Speed ◽  
Gravity Waves ◽  
Large Scale ◽  
Sea Breeze ◽  
Flow Regimes ◽  
Prevailing Wind ◽  
Tropical Islands ◽  
Wind Speeds ◽  
Upward Deflection ◽  
Quantitative Impact

Abstract A set of idealized cloud-permitting simulations is performed to explore the influence of small islands on precipitating convection as a function of large-scale wind speed. The islands are situated in a long narrow ocean domain that is in radiative–convective equilibrium (RCE) as a whole, constraining the domain-average precipitation. The island occupies a small part of the domain, so that significant precipitation variations over the island can occur, compensated by smaller variations over the larger surrounding oceanic area. While the prevailing wind speeds vary over flat islands, three distinct flow regimes occur. Rainfall is greatly enhanced, and a local symmetric circulation is formed in the time mean around the island, when the prevailing large-scale wind speed is small. The rainfall enhancement over the island is much reduced when the wind speed is increased to a moderate value. This difference is characterized by a change in the mechanisms by which convection is forced. A thermally forced sea breeze due to surface heating dominates when the large-scale wind is weak. Mechanically forced convection, on the other hand, is favored when the large-scale wind is moderately strong, and horizontal advection of temperature reduces the land–sea thermal contrast that drives the sea breeze. Further increases of the prevailing wind speed lead to strong asymmetry between the windward and leeward sides of the island, owing to gravity waves that result from the land–sea contrast in surface roughness as well as upward deflection of the horizontal flow by elevated diurnal heating. Small-amplitude topography (up to 800-m elevation is considered) has a quantitative impact but does not qualitatively alter the flow regimes or their dependence on wind speed.

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