======Vortices in Boundary Layer======
=====Experiments by Pauley and Eaton=====

----

====Description====

Flow over an initially two-dimensional turbulent boundary layer with longitudinal
embedded vortices. 3D flow with constant temperature.

===Geometry of the Computational Domain===

At \(x = 0\), two half-delta-wing generators, 20 mm high and 50 mm long, are
mounted at an angle of attack on a flat plate called the "test wall". They are
set up symmetrically on each side of the test wall centreline so that the spacing
between the midway point of the delta wing chord of the generators is 40 mm.
The angle of attack between the chord and the tunnel centreline is 18<sup>o</sup>,
as shown in <imgref cas12-geom>.

The boundary layer is tripped 53 cm upstream of the vortex generators, and the
flat plate extends far enough downstream (to \(x=200cm\)) in order to 
accommodate the region located at \(x = 188\) cm (\(0.16 < y < 6.75\) cm and \(0 \le z \le 15\) cm) 
where the furthest downstream measurements are provided.
  
<imgcaption cas12-geom|Flow geometry>{{ figs:case012:t12.gif |Flow geometry}}</imgcaption>

===Flow Characteristics===

A pair of strong longitudinal vortices and arrays of weaker longitudinal
vortices are both embedded in an otherwise two-dimensional turbulent boundary
layer. The vortices remain close to the wall producing significant levels of
spanwise skin friction and, consequently, a greater rate of streamwise
circulation decrease.

===Flow Parameters===

Air at standard conditions.

Nominal free-stream velocity: \(U_e = 16\) m/s (at the edge of the boundary layer).

===Inflow Conditions===

In the undisturbed case, without the presence of the vortex generators, the flow is two-dimensional
and the boundary layer has the following features at \(x=0\) (the boundary layer is tripped at \(x = -53\) cm):

^ Boundary-layer thickness  |   13 mm  |
^ Momentum thickness Reynolds number  |  \(Re = 1700\)  |
^ Free-stream turbulence level  |  0.2%  |

For those performing simulations, an appropriate strategy could be to run a separate developing 
boundary layer case in order to match these conditions, and use profiles from that as
inlet conditions at a suitable distance upstream of the vortex generators.

====Experimental Details====

Velocity measurements using a miniature five-hole pressure probe whose tip is
2.7 mm in diameter with 0.4 mm pressure ports. Streamwise and spanwise components of 
the skin friction measured using a dual sublayer fence probe.

===Measurement Errors===

Mean flow measurements:

| \(\delta(\text{flow angles})\)  |  \(\pm 0.5^o\)  |
| \(\delta(\text{velocity vector magnitudes})\)  |  \(\pm 5\%\)  |

====Available Measurements====

At two \(x\) positions (\(x=97\) and \(188\) cm) the following measurements are provided:

Contour maps of:

  * First order moments: \(U/U_e\), \(V/U_e\), \(W/U_e\)
  * Second order moments: \(\overline{u^2}/U_e^2\), \(\overline{v^2}/U_e^2\), \(\overline{w^2}/U_e^2\), \(\overline{uv}/U_e^2\), \(\overline{uw}/U_e^2\), \(\overline{vw}/U_e^2\)
  * Third order moments: \(\overline{uuu}/U_e^3\), \(\overline{vvv}/U_e^3\), \(\overline{www}/U_e^3\), \(\overline{uuv}/U_e^3\), \(\overline{uuw}/U_e^3\), \(\overline{uvv}/U_e^3\), \(\overline{uww}/U_e^3\), \(\overline{vvw}/U_e^3\), \(\overline{vww}/U_e^3\), \(\overline{uvw}/U_e^3\)

Available \(x\) stations:

^   \(x\) position  ^  \(y\) range  ^  \(z\) range  ^  filenames  ^
|  \(x = 97\) cm   |  \(0.16 < y < 5.25\) cm  |  \(0 \le z \le 12\) cm  |  3#fcna.dat  |
|  \(x = 188\) cm  |  \(0.16 < y < 6.75\) cm  |  \(0 \le z \le 15\) cm  |  9#fcna.dat  |

The data can be downloaded as compressed archives from the links
below, or as individual files.

  * {{cdata:case012:blvx-allfiles.zip|blvx-allfiles.zip}}
  * {{cdata:case012:blvx-allfiles.tar.gz|blvx-allfiles.tar.gz}}

[[case012-plots|Sample plots]] of selected quantities are available.

^  \(x=97\) cm  ^^  ^  \(x=188\) cm  ^^
^ \(z\) [cm] ^ File ^  ^  \(z\) [cm] ^ File ^
| 0.0   |  {{cdata:case012:3afcna.dat|3afcna.dat}}  | | 0.0   |  {{cdata:case012:9afcna.dat|9afcna.dat}} |
| 0.5   |  {{cdata:case012:3bfcna.dat|3bfcna.dat}}  | | 1.0   |  {{cdata:case012:9bfcna.dat|9bfcna.dat}} |
| 1.0   |  {{cdata:case012:3cfcna.dat|3cfcna.dat}}  | | 2.0   |  {{cdata:case012:9cfcna.dat|9cfcna.dat}} |
| 1.5   |  {{cdata:case012:3dfcna.dat|3dfcna.dat}}  | | 3.0   |  {{cdata:case012:9dfcna.dat|9dfcna.dat}} |
| 2.0   |  {{cdata:case012:3efcna.dat|3efcna.dat}}  | | 4.0   |  {{cdata:case012:9efcna.dat|9efcna.dat}} |
| 2.5   |  {{cdata:case012:3ffcna.dat|3ffcna.dat}}  | | 5.0   |  {{cdata:case012:9ffcna.dat|9ffcna.dat}} |
| 3.0   |  {{cdata:case012:3gfcna.dat|3gfcna.dat}}  | | 5.5   |  {{cdata:case012:9gfcna.dat|9gfcna.dat}} |
| 3.5   |  {{cdata:case012:3hfcna.dat|3hfcna.dat}}  | | 6.0   |  {{cdata:case012:9hfcna.dat|9hfcna.dat}} |
| 4.0   |  {{cdata:case012:3ifcna.dat|3ifcna.dat}}  | | 6.5   |  {{cdata:case012:9ifcna.dat|9ifcna.dat}} |
| 4.5   |  {{cdata:case012:3jfcna.dat|3jfcna.dat}}  | | 7.0   |  {{cdata:case012:9jfcna.dat|9jfcna.dat}} |
| 5.0   |  {{cdata:case012:3kfcna.dat|3kfcna.dat}}  | | 7.5   |  {{cdata:case012:9kfcna.dat|9kfcna.dat}} |
| 5.5   |  {{cdata:case012:3lfcna.dat|3lfcna.dat}}  | | 8.0   |  {{cdata:case012:9lfcna.dat|9lfcna.dat}} |
| 5.0   |  {{cdata:case012:3mfcna.dat|3mfcna.dat}}  | | 8.5   |  {{cdata:case012:9mfcna.dat|9mfcna.dat}} |
| 6.5   |  {{cdata:case012:3nfcna.dat|3nfcna.dat}}  | | 9.0   |  {{cdata:case012:9nfcna.dat|9nfcna.dat}} |
| 7.0   |  {{cdata:case012:3ofcna.dat|3ofcna.dat}}  | | 9.5   |  {{cdata:case012:9ofcna.dat|9ofcna.dat}} |
| 7.5   |  {{cdata:case012:3pfcna.dat|3pfcna.dat}}  | | 10.0  |  {{cdata:case012:9pfcna.dat|9pfcna.dat}} |
| 8.0   |  {{cdata:case012:3qfcna.dat|3qfcna.dat}}  | | 10.5  |  {{cdata:case012:9qfcna.dat|9qfcna.dat}} |
| 8.5   |  {{cdata:case012:3rfcna.dat|3rfcna.dat}}  | | 11.0  |  {{cdata:case012:9rfcna.dat|9rfcna.dat}} |
| 9.0   |  {{cdata:case012:3sfcna.dat|3sfcna.dat}}  | | 11.5  |  {{cdata:case012:9sfcna.dat|9sfcna.dat}} |
| 9.5   |  {{cdata:case012:3tfcna.dat|3tfcna.dat}}  | | 12.0  |  {{cdata:case012:9tfcna.dat|9tfcna.dat}} |
| 10.0  |  {{cdata:case012:3ufcna.dat|3ufcna.dat}}  | | 13.0  |  {{cdata:case012:9ufcna.dat|9ufcna.dat}} |
| 10.5  |  {{cdata:case012:3vfcna.dat|3vfcna.dat}}  | | 14.0  |  {{cdata:case012:9vfcna.dat|9vfcna.dat}} |
| 11.0  |  {{cdata:case012:3wfcna.dat|3wfcna.dat}}  | | 15.0  |  {{cdata:case012:9wfcna.dat|9wfcna.dat}} |
| 11.5  |  {{cdata:case012:3xfcna.dat|3xfcna.dat}}  | |  |   | 
| 12.0  |  {{cdata:case012:3yfcna.dat|3yfcna.dat}}  | |  |   |


====Main References====

  - Pauley, W.R., Eaton, J.K. (1988). [[https://doi.org/10.2514/3.9974|Experimental study of the development of longitudinal vortex pairs embedded in a turbulent boundary layer]]. //AIAA J.//, Vol. 26, p. 816.
  - Pauley, W.R., Eaton, J.K. (1989). Boundary layer turbulence structure in the presence of embedded streamwise vortex pairs. //Proc. 7th Int. Symp. on Turbulent Shear Flows//, Stanford Univ.

----

Indexed data:
<data dbcase semi_confined_flow>
case       : 012
title      : Vortices in Boundary Layer
author*    : Pauley, Eaton
year       : 1987
type       : EXP
flow_tag*  : 3d, 3dbl
</data>