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Experimental study of distributed receptivity coefficients at excitation of Goertler modes by free-stream vortices

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The paper is devoted to an experimental quantitative study of distributed excitation of unsteady Görtler-instability modes in a boundary layer over a concave wall by free-stream vortices (receptivity problem). Experiments are carried out in a low-turbulent wind tunnel under completely controlled disturbance conditions. Investigated receptivity mechanism is found to be rather efficient. It is able to change significantly the growth rates of Görtler vortices (in comparison with the linear-instability growth rates). Extremely difficult task of identification of distributed receptivity coefficients was solved successfully. It was found that the amplitudes of the coefficients reach their maximum values for those Görtler vortices which dimensionless spanwise scales are between 250 and 500. The receptivity coefficients turned out to decrease rather quickly with the streamwise coordinate.

Author(s):

Adnrey Ivanov    
Khristianovich Institute of Theoretical and Applied Mechanics SB RAS
Russian Federation

Yury Kachanov    
Khristianovich Institute of Theoretical and Applied Mechanics SB RAS
Russian Federation

Dmitry Mischenko    
Khristianovich Institute of Theoretical and Applied Mechanics SB RAS
Russian Federation