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The Resolution and Structure of High Reynolds Number Turbulent Boundary Layers Over Rough and Smooth Walls in Pressure Gradient

Version 2 2023-03-20, 19:36
Version 1 2023-03-13, 11:22
dataset
posted on 2023-03-20, 19:36 authored by Vidya VishwanathanVidya Vishwanathan, Daniel J. Fritsch, K. Todd Lowe, William J. Devenport

This dataset contains mean profiles for velocity, Reynolds stress, coefficients of pressure (Cp), and mean boundary layer parameters for a systematic varying family of high Reynolds number (11,000 < Re_theta < 83,000), low Mach number (0.08 < M < 0.20), turbulent boundary layer flows over smooth and very rough (300 < k+ < 900) surfaces in continually varying mild adverse and favorable pressure gradients (-0.91 < beta < 0.71). 

The mean velocity and turbulence stress profiles were measured using particle image velocimetry (PIV), which were acquired at a sampling rate of 1 kHz and were ensemble averaged from 24,839 realizations. The PIV data were measured using two lens magnifications (a baseline and 2x magnified) and the provided data are produced by concatenating the profiles from the two resolutions. The pressure gradient (PG) family was generated on a wind tunnel test section wall by a 0.914-m chord NACA 0012 airfoil. The PG family for each wall-normal profile is denoted by the airfoil angle of attack and the streamwise location (in meters), which are both specified in the title of each file. All provided mean velocity and turbulence data were measured at a Reynolds number per meter of 2.18 million, based on freestream edge velocity, at three pressure gradient cases where the airfoil was at -10, 0, and +12 degrees, at three streamwise positions measured from the coordinate origin at x ~= 2.74 m, x~= 3.31 m, and x ~= 3.94 m, and for two surface conditions, rough and smooth. Provided for each condition are, the streamwise station of measurement (x), skin friction (Cf), boundary layer thickness (delta), displacement thickness (deltaS), momentum thickness (theta), local edge velocity (Ue), streamwise mean velocity profiles, and wall-normal, streamwise, and shear component Reynolds stress profiles in inner and outer coordinates, and uncertainty estimates (averaging and PIV bias) for the mean velocity and stress profiles also in inner and outer coordinates. The velocity components in the streamwise and wall-normal directions are denoted as u and v respectively. The spatial components in the streamwise, wall-normal, and spanwise directions are denoted as x, y, and z respectively. Inner coordinate normalizations of the mean profiles are done based on the shear velocity (ut) and the kinematic viscosity (nu). Outer coordinate normalizations of the the mean profiles are done based on the boundary layer thickness (delta) and the freestream edge velocity (Ue).

Also included in this database are the streamwise varying mean Cp distributions at two Reynolds numbers per meter of 2.18 million and 3.83 million, for twelve pressure gradient distributions generated by the airfoil at angles of attack varying between -10 to +12 degrees in increments of 2 degrees. These mean pressures were measured using both DTC Initium and Esterline 9818/98RK pressure scanners, with varying ranges, and static pressure taps that were installed on the research test wall and connected.

Further information regarding the acquisition parameters and instrumentation used to measure the mean turbulence statistics and pressure distributions can be found in the dissertation titled “The Resolution and Structure of High Reynolds Number Turbulent Boundary Layers Over Rough and Smooth Surfaces in Pressure Gradient.” The mathematical and physical definitions for these variables are also provided in the dissertation. These data are presented in two papers submitted for peer-review and are available as pre-prints (at the time of this data release). The papers are entitled “Spatial Resolution Limitations of Particle Image Velocimetry in High Reynolds Number Turbulent Boundary Layers,” and “History Effects and Wall-Similarity of Non-Equilibrium Turbulent Boundary Layers in Varying Pressure Gradient Over Rough and Smooth Surfaces”. The present data are also companion to the fluctuating pressure and other mean velocity characteristics released in the data repository as part of the dissertation entitled, “Surface Pressure Spectra Beneath High Reynolds Number Smooth and Rough Wall Boundary Layers in Pressure Gradient.”


Related resource -

Title: The Resolution and Structure of High Reynolds Number Turbulent Boundary Layers Over Rough and Smooth Walls in Pressure Gradient

URI: http://hdl.handle.net/10919/113290


 

Group: Center for Research and Engineering in Aero/hydrodynamic Technologies (CREATe), Kevin T. Crofton Department of Aerospace and Ocean Engineering


 

Other References: 

Vishwanathan, V. "The Resolution and Structure of High Reynolds Number Turbulent Boundary Layers Over Rough and Smooth Walls in Pressure Gradient." Virginia Tech, 2023.

Vishwanathan, V., Fritsch, D. J., Lowe, K. T., and Devenport, W. J. "Spatial Resolution Limitations of Particle Image Velocimetry in High Reynolds Number Turbulent Boundary Layers." Experiments in Fluids. In-Review

Vishwanathan, V., Fritsch, D. J., Lowe, K. T., and Devenport, W. J. "History effects and wall similarity of non-equilibrium turbulent boundary layers in varying pressure gradient over rough and smooth surfaces," 12th International symposium on turbulence and shear flow phenomena (TSFP12), Osaka, Japan (19-22 July, 2022). 2022.

Vishwanathan, V., Fritsch, D. J., Lowe, K. T., and Devenport, W. J. “History Effects and Wall-Similarity of Non-Equilibrium Turbulent Boundary Layers in Varying Pressure Gradient Over Rough and Smooth Surfaces.” International Journal of Heat and Fluid Flow. In-Review

Funding

Office of Naval Research N00014-18-1-2455, N00014-19-1-2109, N00014-20-2821

History

Publisher

University Libraries, Virginia Tech

Location

Virginia Tech Stability Wind Tunnel

Corresponding Author Name

Vidya Vishwanathan

Corresponding Author E-mail Address

vidya418@vt.edu

Files/Folders in Dataset and Description

[Smooth.zip] - Folder containing data for the smooth wall case at a reference chord Reynolds number per meter of 2.18e6 for mean velocity and turbulence stress profiles and for both a Reynolds number per meter of 2.18e6 and 3.83e6 for the streamwise coefficients of mean pressure. [#deg_x#p##_MeanVel_MeanReStress.dat] Name nomenclature is as follows; #deg indicates airfoil angle of attack (neg10, 0, or pos12); x#p## indicates streamwise station where “p” is read as “point.” Each data file contains mean velocity profiles, mean Reynolds wall-normal, streamwise, and shear stress profiles, profile uncertainty estimates, and boundary layer characteristic parameters. Velocity and turbulence profiles (in component directions u and v) are normalized on outer coordinates by the boundary layer thickness (delta) and the local edge velocity (Ue). Profiles in inner coordinates are normalized on the local shear velocity (ut) and kinematic viscosity (nu). Data are defined as follows: x[m] = Streamwise measurement station z[m] = Spanwise measurement station Cf[1e3] = Skin friction (multiplied by a factor of 1e3) delta[m] = Boundary layer thickness in meters deltaS[m] = Displacement thickness in meters theta[m] = Momentum thickness in meters Ue[m/s] = Freestream edge velocity in meters/second Tinf[K] = Ambient temperature in Kelvin pin[Pa] = Ambient pressure in Pascals All of the following variables are provided as nondimensional profiles normalized on inner (ut, nu) or outer coordinate (delta, Ue) variables. y = wall-normal position U = Streamwise mean velocity u2 = Streamwise Reynolds normal stress v2 = Wall-normal Reynolds normal stress uv = Reynolds Shear stress d#_Low = Lower bound of uncertainty of the same variable replaced by “#” d#_Up = Upper bound of uncertainty of the same variable replaced by “#” [Cp_vs_x_#M_Rough.dat] - #M indicates the Reynolds number per meter (either 2.18M or 3p83M) where “p” is read as “point.” Each data file contains coefficients of static pressure along the midspan of the measurement test wall when induced to twelve pressure gradient distributions. The streamwise station (x) is provided in the first column in meters. The subsequent twelve columns provide the corresponding coefficient of pressure at a specified airfoil angle of attack which is denoted in the variable header of each column. [Rough.zip] - Folder containing data for the smooth wall case at a reference chord Reynolds number of 2.0e6 Same file specifications as provided for the folder [Smooth.zip]. Only additional provided variables are: ksp^+ = Effective sandgrain roughness normalized on inner coordinates DeltaU^+ = Roughness parameter for mean velocity shift normalized on inner coordinates