Experiments in Fluids

, Volume 37, Issue 3, pp 323–330 | Cite as

Pulsed-wire measurements in the near-wall layer in a reattaching separated flow

  • P. E. HancockEmail author


Pulsed-wire velocity measurements have been made in the near-wall layer, including the viscous sublayer, beneath a separated flow. A method for correcting the error caused by fluctuations in velocity gradient is given, extending the work of Schober et al. (1998). The measurements show that the r.m.s. of the streamwise velocity fluctuations scale closely in accordance with an inner-layer scaling, where the velocity scale, \({u}\ifmmode{'}\else$'$\fi_{\tau } \), is based on the r.m.s. of the wall shear stress fluctuations (measured by means of a pulsed-wire shear stress probe), rather than the mean wall shear stress. The effects of velocity gradient are only significant beneath \({{u}\ifmmode{'}\else$'$\fi_{\tau } y} \mathord{\left/ {\vphantom {{{u}\ifmmode{'}\else$'$\fi_{\tau } y} \nu }} \right. \kern-\nulldelimiterspace} \nu \) of 10 or less.


Wall Shear Stress Velocity Gradient Laminar Boundary Layer Viscous Sublayer Splitter Plate 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

List of symbols


Calibration constant


Function representing mean velocity


Height of fence above splitter plate surface


Length scale of outer-layer structures


Distance between pulsed and sensor wires


r.m.s. of U

\({u}\ifmmode{'}\else$'$\fi_{\tau } \)

Velocity scale based on r.m.s of wall shear stress fluctuation


Instantaneous velocity in x-direction


Instantaneous measured velocity in x-direction


Free-stream reference velocity


Streamwise direction from separation point


Distance from splitter plate surface, in normal direction


Length of separation bubble


Thickness scale in oscillating layer


Blasius laminar boundary layer parameter




Wall shear stress


r.m.s. of wall shear stress fluctuation


Frequency of oscillating layer


Kinematic viscosity

\({} \)

Overbar denotes time average


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Copyright information

© Springer-Verlag 2004

Authors and Affiliations

  1. 1.School of Engineering, Fluids Research CentreUniversity of SurreyGuildfordUK

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