Numerical and experimental investigation of a beveled trailing-edge flow field and noise emission

2016 ◽  
Vol 384 ◽  
pp. 113-129 ◽  
Author(s):  
W.C.P. van der Velden ◽  
S. Pröbsting ◽  
A.H. van Zuijlen ◽  
A.T. de Jong ◽  
Y. Guan ◽  
...  
Author(s):  
Wouter C. van der Velden ◽  
Stefan Pröbsting ◽  
Arjen de Jong ◽  
Alexander van Zuijlen ◽  
Yaoyi Guan ◽  
...  

2016 ◽  
Vol 139 (2) ◽  
Author(s):  
David Demel ◽  
Mohsen Ferchichi ◽  
William D. E. Allan ◽  
Marouen Dghim

This work details an experimental investigation on the effects of the variation of flap gap and overlap sizes on the flow field in the wake of a wing-section equipped with a trailing edge Fowler flap. The airfoil was based on the NACA 0014-1.10 40/1.051 profile, and the flap was deployed with 40 deg deflection angle. Two-dimensional (2D) particle image velocimetry (PIV) measurements of the flow field in the vicinity of the main wing trailing edge and the flap region were performed for the optimal flap gap and overlap, as well as for flap gap and overlap increases of 2% and 4% chord beyond optimal, at angles of attack of 0 deg, 10 deg, and 12 deg. For all the configurations investigated, the flow over the flap was found to be fully stalled. At zero angle of attack, increasing the flap gap size was found to have minor effects on the flow field but increased flap overlap resulted in misalignment between the main wing boundary layer (BL) flow and the slot flow that forced the flow in the trailing edge region of the main wing to separate. When the angle of attack was increased to near stall conditions (at angle of attack of 12 deg), increasing the flap gap was found to energize and improve the flow in the trailing edge region of the main wing, whereas increased flap overlap further promoted flow separation on the main wing suction surface possibly steering the wing into stall.


2006 ◽  
Vol 27 (4) ◽  
pp. 730-736 ◽  
Author(s):  
Daniel W. Shannon ◽  
Scott C. Morris ◽  
Thomas J. Mueller

1997 ◽  
Author(s):  
Charles Knight ◽  
Leonard Peltier ◽  
Charles Knight ◽  
Leonard Peltier

Author(s):  
Dian Li ◽  
Xiaomin Liu ◽  
Lei Wang ◽  
Fujia Hu ◽  
Guang Xi

Previous publications have summarized that three special morphological structures of owl wing could reduce aerodynamic noise under low Reynolds number flows effectively. However, the coupling noise-reduction mechanism of bionic airfoil with trailing-edge serrations is poorly understood. Furthermore, while the bionic airfoil extracted from natural owl wing shows remarkable noise-reduction characteristics, the shape of the owl-based airfoils reconstructed by different researchers has some differences, which leads to diversity in the potential noise-reduction mechanisms. In this article, three kinds of owl-based airfoils with trailing-edge serrations are investigated to reveal the potential noise-reduction mechanisms, and a clean airfoil based on barn owl is utilized as a reference to make a comparison. The instantaneous flow field and sound field around the three-dimensional serrated airfoils are simulated by using incompressible large eddy simulation coupled with the FW-H equation. The results of unsteady flow field show that the flow field of Owl B exhibits stronger and wider-scale turbulent velocity fluctuation than that of other airfoils, which may be the potential reason for the greater noise generation of Owl B. The scale and magnitude of alternating mean convective velocity distribution dominates the noise-reduction effect of trailing-edge serrations. The noise-reduction characteristic of Owl C outperforms that of Barn owl, which suggests that the trailing-edge serrations can suppress vortex shedding noise of flow field effectively. The trailing-edge serrations mainly suppress the low-frequency noise of the airfoil. The trailing-edge serration can suppress turbulent noise by weakening pressure fluctuation.


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