The following is a readme file describing the tabulated data for flow approaching a 45 degree,

forward facing, swept step.  The experiment was performed in a low speed recirculating water

channel in the thermosciences laboratory at Stanford University by Karen A. Flack and James P.

Johnston.  The step is 0.051 m high and 0.102 m wide.  The side walls of the channel are vertical,

approximately 0.25 m apart, and the depth from the bottom to the free surface is 1.05 m. The data

was obtained at four measurement stations on a line 0.60 m above, and parallel to the channel

floor. The measurement stations are referenced upstream of the step and locations are given as

distances on a line perpendicular to the step: 0.305m, 0.146m, 0.114m, and 0.076m.  The final

station is just downstream of the three-dimensional detachment line which occurs at 0.089m (or

approximately 1.5 step heights) upstream of the step.  Details of the experiment can be found in:



Flack, K.A. and Johnston, J.P., (1993) "Near-wall investigation of three-dimensional turbulent

boundary layers," Thermosciences Division,  Stanford University, Stanford CA, Report MD-63.



Copies of the report may be obtained from the first author.

Professor Karen A. Flack

Department of Mechanical Engineering

United States Naval Academy

Annapolis, MD 21402-5042

(410)293-6500

flack@usna.navy.mil



Professor James P. Johnston

Department of Mechanical Engineering

Stanford University

Stanford, CA 94305-3030

(415)723-4024

johnston@stokes.standford.edu



Tabulated data from the experiment is given in five text files.  The first file, step.txt, lists the flow

conditions and parameters for the four measurement locations. The data is given in standard SI

units (m, m/s, C) and all angles are given in degrees. The columns for the flow conditions and

flow parameters (step.txt) are:

file name, location, water temperature, freestream velocity, delta99, momentum thickness

Reynolds number, wall shear stress, shear velocity,  and skin friction coefficient.



All data is referenced to a right hand coordinate system based on the upstream tunnel coordinates,

where x (u) is the streamwise direction, y (v) is the wall normal direction and z (w) is the

spanwise direction.  The values for the spanwise component of velocity (w) are negative since the

flow is turned by the step in the negative z direction.  Mean velocities are denoted by U, V, and

W, and fluctuating velocities are denoted by u', v', and w'. The columns for the tabulated data

(step1.txt - step4.txt) are as follows:

y, U, V, W, u', v', w', u'v', u'w', v'w', u'u'u', v'v'v', w'w'w', u'u'v', u'u'w', v'v'u', v'v'w',

w'w'u', w'w'v', u'v'w', u'u'u'u', v'v'v'v', w'w'w'w'.