INFLUENCE OF THE ANGLE OF ATTACK OF A PLATE LOCATED IN THE TURBULENT BOUNDARY LAYER ON SKIN FRICTION

The author has presented results of numerical modeling of the infl uence of the angle of attack of a thin width-limited plate with a short chord on the velocity fi eld of the internal region of a turbulent boundary layer (TBL) and skin friction. The computations were performed by the large eddy simulation (LES) method at the Reynolds number Reθ = 540 calculated from the velocity on the channel axis and the momentum thickness. Changes in the average and pulsation characteristics of the three-dimensional velocity fi eld under the impact of the wake of the plate and of tip vortices as functions of the angle of attack of the plate in the range ±1^o have been analyzed. It has been shown that a determining infl uence on the formation of the velocity fi eld is exerted by the tip vortices whose vorticity is opposite with the positive and negative angles of attack. The mean value of the skin-friction coeffi cient decreases by 6% at the positive angle of attack and by 14% at the negative angle with respect to the value of this coeffi cient in an unperturbed TBL.
The author has presented results of numerical modeling of the infl uence of the angle of attack of a thin width-limited plate with a short chord on the velocity fi eld of the internal region of a turbulent boundary layer (TBL) and skin friction. The computations were performed by the large eddy simulation (LES) method at the Reynolds number Reθ = 540 calculated from the velocity on the channel axis and the momentum thickness. Changes in the average and pulsation characteristics of the three-dimensional velocity fi eld under the impact of the wake of the plate and of tip vortices as functions of the angle of attack of the plate in the range ±1^o have been analyzed. It has been shown that a determining infl uence on the formation of the velocity fi eld is exerted by the tip vortices whose vorticity is opposite with the positive and negative angles of attack. The mean value of the skin-friction coeffi cient decreases by 6% at the positive angle of attack and by 14% at the negative angle with respect to the value of this coeffi cient in an unperturbed TBL.
Author:  V. L. Zhdanov
Keywords:  turbulent boundary layer, velocity field, skin friction, vortex generator, wake, tip vortices, LES
Page:  1012 - 1026