Database: Hot-wire data from Influence of Reynolds Number on the Pressure Gradient of Turbulent Channel Flow with Heterogeneous Roughness

This data set contains the measurement data from hot wire measurements presented in the paper "Influence of Reynolds number on the Pressure Gradient of Turbulent Channel Flow with Heterogeneous Roughness" by C. Schmidt, P. Sujar-Garrido, U. Schmitgen and B. Frohnapfel published in the Journal of Fluid Mechanics in 2026.
A complementing dataset contains the presented data from pressure measurements.

The dataset contains three folders, one with the data from the wall-normal measurements for the strip-type surfaces, the other for the checkerboard pattern. The checkerboard pattern folder is further divided into two folders containing the results from the two measurement positions (see Fig. 3).
The third folder contains the data from the measurements of the centreline velocity, this folder is split into two subfolders. One is containing the data from the centreline measurement along the surface with the perpendicular strips, the other from the checkerboard pattern.

Each data file name is a combination of the surface's label (see Tab. 2) and the Reynolds number at which the hot wire measurement is taken. In case of the checkerboard data, also the position of the measurement is included.

Meaning of the columns for the wall-normal measurements:
s/delta - ratio of strip width or checkerboard square side length s to channel half-height delta
W - channel width in mm
delta_avg - measured mean channel half-height in mm
z - measurement position in spanwise direction in mm
y - measurement position in wall-normal direction in mm
z/delta - spanwise measurement position normalised by delta
y/delta - wall-normal measurement position normalised by delta
T_samp - sampling time per data point in s
f_samp - sampling frequency in Hz
Re_b - channel bulk Reynolds number
nu - kinematic viscosity in m^2/s
U_b - channel bulk velocity in m/s
U - mean velocity in m/s
u_rms - rms of the velocity in m/s
u_skw - skewness of the velocity
u_flat - flatness of the velocity

Meaning of the columns for the centreline measurements:
x - measurement position in streamwise direction in mm
x/delta - streamwise measurement position normalised by delta
U_CL-<U_CL>_x/U_b - difference of the centreline velocity to the streamwise ensemble average normalised with the bulk velocity