READ ME File For 'Dataset for Effects Of Heterogeneous Surface Geometry On Secondary Flows In Turbulent Boundary Layers' Dataset DOI: 10.5258/SOTON/D1155 Date of data collection: 1/6/2016 - 31/7/2017 Licence: CC BY Related projects: EP/L006383/1, EP/P021476/1 This dataset presents the experimental data described in "Medjnoun et al., Effects of heterogeneous surface geometry on secondary flows in turbulent boundary layers, JFM, 2020”. DOI: 10.1017/jfm.2019.1014. PLEASE FOLLOW THE DOI FOR THE PAPER TO CITE WHEN REFERRING TO THE DATA. The data is presented for each figure containing important data in the paper (filenames are given accordingly). Using the data provided and normalization parameters (where applicable), the plots in the paper could be reproduced. The quantities are saved in .mat files whose labels are explained below. Further Information regarding the data files: 1. Data for figure 3 is given in Figure_3.mat. The file contains: - Cf_star: A 6x4 matrix that contains the different skin friction coefficients data for each surface (1 to 6 for HS1 to HS6) at different Reynolds numbers (1 to 4 for 10, 15, 20 and 25 m/s) - Rex: Reynolds number based on the fetch in a 6x4 cell in the same order as Cf_star - Cf_smooth: Smooth wall skin friction coefficient taken from a previous study at relatively matched Rex - Rex_smooth: Reynolds numbers at which the smooth wall skin friction coefficients were determined 2. Data for figure 4, 5, 6 and 8 are given in Figure_4_5_6_8.mat. The file contains: - Delta: A 1x6 cell array from HS1 to HS6, containing the span-averaged boundary layer thickiness (m) - Uinf: // // // // //, containing the free-stream speeds (m/s) - X_profile: // // // // //, containing the spanwise coodrinates (m) - Y_profile: // // // // //, containing the wall-normal coodrinates (m) - U, V, W: // // // // //, containing the mean streamwise, wall-normal and spanwise velocity maps (m) - Ss: // // // // // //, containing the vorticity signed swirling strength maps (1/s) - Ruv,Duv,TOTuv: // // // // //, containing the Reynods, dispersive and total shear stress maps (m^2/s^2) 3. Data for figure 9 are given in Figure_9.mat. The file contains: - Delta: A 1x6 cell array from HS1 to HS6, containing the span-averaged boundary layer thickiness (m) - Y_profile: // // // //, containing the wall-normal coodrinates (m) - U_span_av: // // // //, containing the span_averaged mean streamwise velocity profile (m/s) - Ruu_span_av: // // // //, containing the span_averaged mean streamwise variance profile (m^2/s^2) - Rvv_span_av: // // // //, containing the span_averaged mean wall-normal variance profile (m^2/s^2) - Rww_span_av: // // // //, containing the span_averaged mean spanwise variance profile (m^2/s^2) - Ruv_span_av: // // // //, containing the span_averaged mean Reynolds shear stress profile (m^2/s^2) - Duv_span_av: // // // //, containing the span_averaged mean dispersive shear stress profile (m^2/s^2) - Tuv: // // // // //, containing the span_averaged mean total shear stress profile (m^2/s^2) 4. Data for figure 10 are given in Figure_10.mat. The file contains: - Delta: A 1x6 cell array from HS1 to HS6, containing the span-averaged boundary layer thickiness (m) - Y_profile: // // // //, containing the wall-normal coodrinates (m) - U_span_av: // // // //, containing the span_averaged mean streamwise velocity profile (m/s) - Uinf: // // // // //, containing the free-stream speeds (m/s) - Udefect: // // // //, containing the span_averaged mean streamwise velocity profile in defect form (m/s) - u_span_av: // // // //, containing the span_averaged mean streamwise turbulence profile (m/s) 5. Data for the subfigures 11 are given in Figure_11_a,b,c,d,e,f,g,h,i,j,k,l.mat. The files contain: - X: A MxN matrix, containing the spanwise coordinates in the form of a meshgrid (m) - Y: // // //, containing the wall-normal coordinates in the form of a meshgrid (m) - Ruu: // // //, containing the the autocorrelation coefficient of the streamwise velocity fluctuations 6. Data for figure 12 is given in Figure_12.mat. The file contains: - Lxx: A 1x6 cell array from HS1 to HS6, containing the autocorrelation length scale (m) - Theta: // // // //, containing the coherent structure inclination (degree) - z_S: // // // //, containing the normalised spanwise coordinates 7. Data for figure 13 is given in Figure_13.mat. The file contains: - Kth: A 1x6 cell array from HS1 to HS6, containing the kinetic energy threshold - Kin: // // // //, containing the freestream kinetic energy level - Tortuosity: // // // //, containing TNTI tortuosity within one wavelength 8. Data for figure 14 is given in Figure_14_a.mat, Figure_14_b.mat, Figure_14_c.mat and Figure_14_d.mat. The files contain: - y_dx: A 1xN array, containing the wall-normal coordinates normalised with the spanwise averaged boundary layer thickness - z_Sx: A Mx1 array, containing the spanwise coordinates normalised with the spanwise spacing - U_Uix: A MxN matrix, containing an instantaneous velocity maps - Yix: A MxN matrix, containing the ensemble average occurence of the TNTI x in the above quantities represents each subfigure a,b,c and d 9. Data for figure 15a and b is given in Figure_15_a.mat and Figure_15_b.mat. The files contain: - y_dl_peak: A 1xN array, containing the wall-normal coordinates normalised with the local boundary layer thickness at the peak - y_dl_mid: A 1xN array, containing the wall-normal coordinates normalised with the local boundary layer thickness at the mid-peak-valley - y_dl_val: A 1xN array, containing the wall-normal coordinates normalised with the local boundary layer thickness at the valley - gamma_peak: A 1xN array, containing the local intermittency at the peak - gamma_mid: A 1xN array, containing the local intermittency at the mid-peak-valley - gamma_val: A 1xN array, containing the local intermittency at the valley 10. Data for figure 15c is given in Figure_15_c.mat. The file contains: - y_dl_peak: A 1xN array, containing the wall-normal coordinates normalised with the local boundary layer thickness at the peak - y_dl_mid: A 1xN array, containing the wall-normal coordinates normalised with the local boundary layer thickness at the mid-peak-valley - y_dl_val: A 1xN array, containing the wall-normal coordinates normalised with the local boundary layer thickness at the valley - pdf_peak: A 1xN array, containing the pdf of the local intermittency at the peak - pdf_mid: A 1xN array, containing the pdf of the local intermittency at the mid-peak-valley - pdf_val: A 1xN array, containing the pdf of the local intermittency at the valley 11. Data for figure 15d is given in Figure_15_d.mat. The file contains: - y_d: A 1x6 cell array for each case from HS1 to HS6, containing the wall-normal coordinates normalised with the span averaged boundary layer thickness - pdf: A 1x6 cell array for each case from HS1 to HS6, containing the global probability density function of the TNTI locations