DOI: 10.18150/litmf2
title: Data for publication: Hot-wire spatial resolution issues in adverse pressure gradient turbulent boundary layers

description: Data of the velocity profiles presented in: Hot-wire spatial resolution issues in adverse pressure gradient turbulent boundary layers.The effect of a finite length of hot-wire probe sensor length on the measured streamwise velocity fluctuations is well understood in canonical wall-bounded flow, where the small-scale energy has been found to be universal and invariant with Reynolds number. A straightforward application of that assumption to non-canonical flows such as strong adverse pressure gradient (APG) flows has, however, been hampered since the effect of Re and APG could not conclusively be studied separately due to the lack of data with a clear scale separation. The present experimental investigation at Reτ≈4000 in weak, moderate and strong APGs with different wire length shows that spatial averaging effects are not only limited to the inner layer. A note of caution is hence warranted for measurements that seemingly try to take the bias effect of spatial attenuation into account by performing measurements with albeit long but fixed viscous-scaled wire length.Files contains flow parameters and velocity statistics at the locations from the inlet to the APG section 'x'.File List: "wAPG_x=1000_036_24U.txt""wAPG_x=1000_041_24U.txt""wAPG_x=1000_043_24U.txt""mAPG_x=600_061_24U.txt""mAPG_x=600_064_24U.txt""mAPG_x=600_066_24U.txt""mAPG_x=800_060_24U.txt""mAPG_x=800_065_U24.txt""mAPG_x=800_101_U24.txt""mAPG_x=1200_050_24U.txt""mAPG_x=1200_059_24U.txt""sAPG_x=500_022_24U.txt""sAPG_x=500_029_24U.txt""sAPG_x=500_106_24U.txt""sAPG_x=700_023_24U.txt""sAPG_x=700_031_24U.txt""sAPG_x=900_024_24U.txt""sAPG_x=900_107_24U.txt"Filename description:w - weakm - moderates - strongAPG - adverse pressure gradientx - distance from the ZPG inlet in millimetres036 .. 107 data serial number24U - inlet velocity 24m/sl+ - length of the wire in viscous units is provided inside each of the file. Relationship between files, if important: The similar file names except the data serial number correspond to different wire length at the same location/flow conditions.Additional related data collected that was not included in the current data package: Dataset concerning statistics were calculated from the velocity signals collected during experiment and available on request after sending an email to artur.drozdz@pcz.pl.Remaining statistics were taken from the measurement presented in following papers:Dróżdż A, Niegodajew P, Romańczyk M, Elsner W. Effect of Reynolds number on turbulent boundary layer approaching separation. Exp Therm Fluid Sci 2021;125:110377. https://doi.org/10.1016/j.expthermflusci.2021.110377Description of methods used for collection/generation of data: procedures and experimental setup was provided in the publication Dróżdż A, Örlü R, Sokolenko V, Schlatter P, Elsner W, Niegodajew P. Hot-wire spatial resolution issues in adverse pressure gradient turbulent boundary layers. Measurement 2024;237:115229 https://doi.org/10.1016/j.measurement.2024.115229Methods for processing the data: Statistics were computed within LabView environment during measurements with the use of the standard functions 'Statistics'. Data scaling was performed using the friction velocity, ut_Correc.Clauser, estimated by the method described in the referenced literature: Niegodajew P, Dróżdż A, Elsner W. A new approach for estimation of the skin friction in turbulent boundary layer under the adverse pressure gradient conditions. Int J Heat Fluid Flow 2019;79:108456. https://doi.org/10.1016/j.ijheatfluidflow.2019.108456.Instrument- or software-specific information needed to interpret the data: NAStandards and calibration information, if appropriate: Calibration of the hot-wire was conducted during the measurements for each data series number, as outlined in the associated publication, with an uncertainty of 1%.Environmental/experimental conditions: Flow temperature and atmospheric pressure conditions measured in the laboratory at Częstochowa University of Technology.Describe any quality-assurance procedures performed on the data: The velocity profile measurements were conducted at least three times using varying wire lengths. The collected velocity signals include details on acquisition parameters and constants of the hot-wire calibration curve.