READ ME File For 'dataset_effect_of_serrated_trailing_edges_on_aerofoil_tonal_noise.zip'

Dataset DOI: 10.5258/SOTON/D1520

Author: Matthieu Bernard Roger Gelot, University of Southampton

This dataset supports the publication:
AUTHORS: Matthieu B. R. Gelot and Jae Wook Kim
TITLE: Effect of serrated trailing edges on aerofoil tonal noise
JOURNAL: Journal of Fluid Mechanics
PAPER DOI IF KNOWN:

This dataset contains:

The present dataset contains all processed and raw data needed to generate the figures in the associated paper.
It features .dat ASCII files, .plt and .szplt binary files which need to be open using Tecplot 360 software.
Each file contained in the dataset is titled with the corresponding figure number followed by a short description of the content.

The figures are as follows:

Fig. 1 A bird's eye view of the surface mesh for the BTE and STE2 aerofoils (20% of total cells shown) on the left and a cross-sectional view of the interior mesh of the BTE case (25% of total cells shown) on the right.
Fig. 2 Wall-unit grid spacings used in the BTE case where \Delta s+ is the streamwise curvilinear spacing, \Delta z+ is the spanwise spacing and \Delta n+ is the wall-normal spacing.
Fig. 3 Time-averaged profiles of the pressure coefficient Cp and skin friction coefficient Cf. The BTE profile is spanwise-averaged whereas the STE profiles are extracted from the mid-span cross-section. The laminar separation bubble (LSB) range is also depicted.
Fig. 4 (a) Contour maps of the PSD of wall pressure fluctuations (WPF) on the suction side of the BTE case in log scale at five different frequencies, where the black dashed line indicates the transition location; and, (b) spanwise-averaged PSDs of WPF on the suction side extracted at four different streamwise locations: x1/Lc = 0.72, x2/Lc = 0.80, x3/Lc = 0.90 and x4/Lc = 0.99.
Fig. 5 A wavenumber-frequency spectrum of the streamwise velocity fluctuation (the magnitude of the Fourier transform) extracted on a mid-span plane along a path-line displaced from the wall by about 20% of the boundary layer thickness at the TE in the BTE case. Least square best fit line with a slope of 0.223 is also displayed.
Fig. 6 Visualised acoustic feedback loop in a mid-span plane showing flood of filtered vertical cross-stream velocity time derivative fluctuation dv/dt at fL_c/a_{\infty} = 3.9, contour lines of acoustic wave front (solid grey), extrapolated acoustic wave front in the near field (dashed grey) and the laminar separation bubble canopy (solid pink) in the BTE case.
Fig. 7 Close-up on the velocity vector field near the LSB detachment in the BTE case. Snapshots are synchronised with the ones in figure 6.
Fig. 8 Time evolution of the laminar separation bubble over a period (t8-t1)a_{\infty}/Lc = 0.28 in the BTE case. Frames are extracted with a time step of (\Delta t)a1/Lc = 0.04. The white dashed lines depict the periodic detachment of the secondary LSB.
Fig. 9 Contour map of the divergence of velocity \partial(uj/a_{\infty})/\partial(xj/Lc) on a mid-span plane comparing the BTE, STE1 and STE2 cases.
Fig. 10 Power spectral density of far field sound pressure fluctuations (loading noise from (2.4)) over a narrow circular arc 80^\circ < \theta < 100^\circ of a radius of r/Lc = 10 centered at the TE of the baseline aerofoil (x/Lc; y/Lc; z/Lc) = (1; 0; 0): (a) the individual PSDs and (b) the relative difference of the STE cases to the baseline in decibels.
Fig. 11 One-third-octave band power spectral density of far field sound pressure fluctuations (loading noise from (2.4)) over a narrow circular arc 80^\circ < \theta < 100^\circ of a radius of r/Lc = 10 centered at the TE of the baseline aerofoil (x/Lc; y/Lc; z/Lc) = (1; 0; 0): (a) the individual PSDs and (b) the relative difference of the STE cases to the baseline in decibels.
Fig. 12 Surface contour maps of the Fourier transform of the wall pressure jump at the tonal frequency fLc/a_{\infty} = 3.9: (a) the magnitude in log scale and (b) the phase distribution. The reference phase is the spanwise averaged value at the transition location (x/Lc = 0.72).
Fig. 13 Time evolution of the laminar separation bubble over a period (t8 - t1)a_{\infty}/Lc = 0.28 in the STE2 case. Frames are extracted with a time step of (\Delta t)a_{\infty}/Lc = 0.04.
Fig. 14 Spanwise variation of the phase of the wall pressure fluctuations taken at the tonal frequency fLc/a_{\infty} = 3.9: (a) at the transition location and (b) along the TE.
Fig. 15 Time-averaged profiles of the pressure coefficient Cp and skin friction coefficient Cf. The BTE profiles are spanwise-averaged.
Fig. 16 Time-averaged profiles of the pressure coefficient Cp and skin friction coefficient Cf. The STE profiles are extracted at the tip of the serrations.
Fig. 17 Power spectral density of far field sound pressure fluctuations (loading noise from (2.4)) over a narrow circular arc 80^\circ < \theta < 100^\circ of a radius of r/Lc = 10 centered at the TE of the baseline aerofoil (x/Lc; y/Lc; z/Lc) = (1; 0; 0) comparing two span lengths: (a) the individual PSDs and (b) the relative difference of the STE2 cases to the baseline in decibels.
Fig. 18 One-third-octave band power spectral density of far field sound pressure fluctuations (loading noise from (2.4)) over a narrow circular arc 80^\circ < \theta < 100^\circ of a radius of r/Lc = 10 centered at the TE of the baseline aerofoil (x/Lc; y/Lc; z/Lc) = (1; 0; 0) comparing two span lengths: (a) the individual PSDs and (b) the relative difference of the STE2 cases to the baseline in decibels.
Fig. 19 Comparison of 5% span (top) and 10% span (bottom) for STE2 case with surface contour maps of the Fourier transform of the wall pressure jump at the tonal frequency fLc/a_{\infty} = 3.9: (a) the magnitude in log scale and (b) the phase distribution.
Fig. 20 Comparison of the spanwise variation of the phase of the wall pressure fluctuations taken at the tonal frequency fLc/a_{\infty} = 3.9 along the TE between STE2 and STE2-ext.. Lz = 0.1Lc and the distribution for STE2 is repeated two times.

Date of data collection: January - May 2020

Information about geographic location of data collection: Southampton, UK

Licence: CC BY

Related projects: None

Date that the file was created: August, 2020