scholarly journals Experimental study on supersonic plate boundary layer transition under pulsed arc plasma excitation control

2020 ◽  
Vol 69 (15) ◽  
pp. 155201
Author(s):  
Bing-Liang Tang ◽  
Shan-Guang Guo ◽  
Guo-Zheng Song ◽  
Yan-Hao Luo
Keyword(s):  
Boundary Layer ◽  
Experimental Study ◽  
Plate Boundary ◽  
Boundary Layer Transition ◽  
Excitation Control ◽  
Arc Plasma ◽  
Layer Transition ◽  
Plasma Excitation ◽  
Pulsed Arc

Evolution of Lagrangian coherent structures in a cylinder-wake disturbed flat plate boundary layer

2016 ◽  
Vol 792 ◽  
pp. 274-306 ◽  
Author(s):  
Guo-Sheng He ◽  
Chong Pan ◽  
Li-Hao Feng ◽  
Qi Gao ◽  
Jin-Jun Wang
Keyword(s):  
Boundary Layer ◽  
Turbulent Boundary Layer ◽  
Coherent Structures ◽  
Plate Boundary ◽  
Boundary Layer Transition ◽  
Lagrangian Coherent Structures ◽  
Hydrogen Bubble ◽  
Layer Transition ◽  
Low Speed Streaks ◽  
Flat Plate Boundary Layer

Evolution of Lagrangian coherent structures (LCS) in a flat plate boundary layer transition induced by the wake of a circular cylinder is investigated. Both hydrogen bubble visualization and particle image velocimetry (PIV) techniques are used. It is found that downstream of the cylinder, the disturbance in the boundary layer experiences a fast growth followed by a slow decay in the transition. Lagrangian coherent structures are revealed by qualitative hydrogen bubble visualizations and quantitative finite-time Lyapunov exponents (FTLE) fields derived from the PIV data. The evolution of the LCS is considered from the very beginning of the transition up to when the boundary layer becomes fully developed turbulent flow. The mean convection velocity and average inclination angle of the LCS are first extracted from the FTLE fields. The streamwise length of the low-speed streaks seems to increase, while their spanwise distance decreases in the boundary layer transition. Proper orthogonal decomposition (POD) of the PIV data shows that low-speed streaks associated with the hairpin vortices and hairpin packets are the dominant coherent structures close to the wall in the transitional and turbulent boundary layer. The POD modes also reveal a variety of scales in the turbulent boundary layer. Moreover, it is found that large-scale coherent structures can modulate the amplitude of the small-scale ones.

Sign in / Sign up

Export Citation Format

Share Document