Global Instability Analysis of Unswept- and Swept-Wing Transonic Buffet Onset

2018 ◽  
Author(s):  
Jeffrey D. Crouch ◽  
Andrey Garbaruk ◽  
Michael Strelets
Keyword(s):  
Swept Wing ◽  
Global Instability ◽  
Instability Analysis ◽  
Transonic Buffet

Modal Decomposition Analysis of Three-Dimensional Transonic Buffet Phenomenon on a Swept Wing

AIAA Journal ◽  
2018 ◽  
Vol 56 (10) ◽  
pp. 3938-3950 ◽  
Author(s):  
Yuya Ohmichi ◽  
Takashi Ishida ◽  
Atsushi Hashimoto
Keyword(s):  
Three Dimensional ◽  
Decomposition Analysis ◽  
Swept Wing ◽  
Modal Decomposition ◽  
Transonic Buffet

Experimental analysis of transonic buffet on a 3D swept wing using fast-response pressure-sensitive paint

2018 ◽  
Vol 59 (6) ◽  
Author(s):  
Yosuke Sugioka ◽  
Shunsuke Koike ◽  
Kazuyuki Nakakita ◽  
Daiju Numata ◽  
Taku Nonomura ◽  
...  
Keyword(s):  
Experimental Analysis ◽  
Fast Response ◽  
Pressure Sensitive Paint ◽  
Swept Wing ◽  
Pressure Sensitive ◽  
Response Pressure ◽  
Transonic Buffet

Mechanisms of flow tripping by discrete roughness elements in a swept-wing boundary layer

2016 ◽  
Vol 796 ◽  
pp. 158-194 ◽  
Author(s):  
Holger B. E. Kurz ◽  
Markus J. Kloker
Keyword(s):  
Boundary Layer ◽  
Roughness Element ◽  
Three Dimensional ◽  
Finite Size ◽  
Roughness Height ◽  
Swept Wing ◽  
Global Instability ◽  
Critical Height ◽  
Roughness Elements ◽  
Dimensional Boundary

The effects of a spanwise row of finite-size cylindrical roughness elements in a laminar, compressible, three-dimensional boundary layer on a wing profile are investigated by direct numerical simulations (DNS). Large elements are capable of immediately tripping turbulent flow by either a strong, purely convective or an absolute/global instability in the near wake. First we focus on an understanding of the steady near-field past a finite-size roughness element in the swept-wing flow, comparing it to a respective case in unswept flow. Then, the mechanisms leading to immediate turbulence tripping are elaborated by gradually increasing the roughness height and varying the disturbance background level. The quasi-critical roughness Reynolds number above which turbulence sets in rapidly is found to be $Re_{kk,qcrit}\approx 560$ and global instability is found only for values well above 600 using nonlinear DNS; therefore the values do not differ significantly from two-dimensional boundary layers if the full velocity vector at the roughness height is taken to build $Re_{kk}$. A detailed simulation study of elements in the critical range indicates a changeover from a purely convective to a global instability near the critical height. Finally, we perform a three-dimensional global stability analysis of the flow field to gain insight into the early stages of the temporal disturbance growth in the quasi-critical and over-critical cases, starting from a steady state enforced by damping of unsteady disturbances.

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