Velocity statistics for rough-wall turbulent boundary layer flow over LEGO roughness elements in different layouts

This dataset presents 2D PIV experimental data collected over a range of twelve urban roughnesses with different frontal and plan solidities. These are described in:

[1] Placidi, M., Ganapathisubramani, B. (2015). Effects of frontal and plan solidities on aerodynamic parameters and the roughness sublayer in turbulent boundary layers. Journal of Fluid Mechanics, 782, 541–566. http://doi.org/10.1017/jfm.2015.552

[2] Placidi, M., Ganapathisubramani, B. (2018). Turbulent Flow Over Large Roughness Elements: Effect of Frontal and Plan Solidity on Turbulence Statistics and Structure. Boundary-Layer Meteorology, 167, 99–121. http://doi.org/10.1007/s10546-017-0317-3

PLEASE CITE THESE PAPERS AND THIS DATASET DOI WHEN USING THE DATA.

Please contact Dr Marco Placidi ([e-mail]) or Prof Bharathram Ganapathisubramani ([e-mail]) for any queries on the dataset.
$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$

Format of the dataset:

d = Virtual origin [mm]
delta = Boundary layer thickness (delta99 [mm])
deltas = Displacement thickness [mm]
dyn_visc_air = Air dynamic viscosity [Kg/(m s)]
h = Height of the roughness [mm]
K = Acceleration parameter as in [1]
rho_air = Air density [kq/m^3]
run = Case ID as in [1] and [2]
theta = Momentum thickness [mm]
U = Mean streamwise velocity [m/s]
U_edge = Mean streamwise velocity at the edge of the boundary layer [m/s]
utau = Skin friction velocity [m/s] based on drag measurements
uu = Streamwise velocity fluctuations
uv = Reynolds shear stresses
V = Mean wall-normal velocity [m/s]
vv = Wall-normal velocity fluctuations
X = Streamwise coordinate [mm]
Y = Wall-normal coordinate [mm]
y0 = Roughness length [mm]

Additional notes on the dataset:

- The 2D PIV dataset has been averaged across the Field of View in the streamwise direction to obtain 1D profiles.

- utau is measured directly by means of a floating-element drag balance as described in [1].

- y0,d, are obtained via best fitting the velocity profiles as in [1].

- The entire dataset has been filtered to match the local resolution for all cases, as discussed in [1].

- The acceleration parameter is defined in [1], and it is calculated from 2D PIV data across the size of the drag balance sensing element (i.e. 200 mm x200 mm). As such, it is affected by a significant experimental uncertainty. Additional verification of ZPG conditions were obtained via Pitot tube measurements between the inlet and outlet of the tunnel test section. The pressure gradient was considered negligible.