Experimental study of the development of longitudinal vortex pairs embedded in a turbulent boundary layer

AIAA Journal ◽  
1988 ◽  
Vol 26 (7) ◽  
pp. 816-823 ◽  
Author(s):  
Wayne R. Pauley ◽  
John K. Eaton
Keyword(s):  
Boundary Layer ◽  
Experimental Study ◽  
Turbulent Boundary Layer ◽  
Longitudinal Vortex ◽  
Vortex Pairs

The Effect of Embedded Longitudinal Vortex Arrays on Turbulent Boundary Layer Heat Transfer

1994 ◽  
Vol 116 (4) ◽  
pp. 871-879 ◽  
Author(s):  
W. R. Pauley ◽  
J. K. Eaton
Keyword(s):  
Heat Transfer ◽  
Boundary Layer ◽  
Turbulent Boundary Layer ◽  
Secondary Flow ◽  
Layer Structure ◽  
Longitudinal Vortex ◽  
Vortex Pairs ◽  
Dimensional Boundary ◽  
Minimal Modification ◽  
Vortex Patterns

Heat transfer and fluid mechanics data were obtained for a turbulent boundary layer with arrays of embedded streamwise vortices containing both counterrotating and corotating vortex pairs. The data show that these arrays can cause both large local variations in the heat transfer rate and significant net heat transfer augmentation over large areas. Close proximity of other vortices strongly affects the development of the vortex arrays by modifying the trajectory that they follow. The vortices in turn produce strong distortion of the normal two-dimensional boundary layer structure, which is due to their secondary flow. When one vortex convects another toward the wall, a strong boundary layer distortion occurs. The heat transfer is elevated where the secondary flow is directed toward the wall and reduced where the secondary flow is directed away from the wall. When adjacent vortices lift their neighbor away from the wall, minimal modification of the heat transfer results. The primary influence of grouping multiple vortex pairs into arrays is the development of stable patterns of vortices. These stable vortex patterns produce vortices that interact with the boundary layer and strongly modify the heat transfer far downstream, even where the vortices have decayed in strength.

Heat Transfer Effects of a Longitudinal Vortex Embedded in a Turbulent Boundary Layer

1987 ◽  
Vol 109 (1) ◽  
pp. 16-24 ◽  
Author(s):  
P. A. Eibeck ◽  
J. K. Eaton
Keyword(s):  
Heat Transfer ◽  
Boundary Layer ◽  
Turbulent Boundary Layer ◽  
Delta Wing ◽  
Stanton Number ◽  
Longitudinal Vortex ◽  
Test Facility ◽  
Pressure Probe ◽  
Transfer Effects ◽  
Heat Transfer Effects

The heat transfer effects of an isolated longitudinal vortex embedded in a turbulent boundary layer were examined experimentally for vortex circulations ranging from Γ/U∞δ99 = 0.12 to 0.86. The test facility consisted of a two-dimensional boundary-layer wind tunnel, with a vortex introduced into the flow by a half-delta wing protruding from the surface. In all cases, the vortex size was of the same order as the boundary-layer thickness. Heat transfer measurements were made using a constant-heat-flux surface with 160 embedded thermocouples to provide high resolution of the surface-temperature distribution. Three-component mean-velocity measurements were made using a four-hole pressure probe. Spanwise profiles of the Stanton number showed local increases as large as 24 percent and decreases of approximately 14 percent. The perturbation to the Stanton number was persistent to the end of the test section, a length of over 100 initial boundary-layer thicknesses. The weakest vortices examined showed smaller heat transfer effects, but the Stanton number profiles were nearly identical for the three cases with circulation greater than Γ/U∞δ99 = 0.53 cm. The local increase in the Stanton number is attributed to a thinning of the boundary layer on the downwash side of the vortex.

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