README file for experimental data and two-phase flow numerical simulation of intense sediment transport / sheet flow All the data present in this archive can also be retrieved from the LEGI dap server at: http://servdap.legi.grenoble-inp.fr/meige/15SHEET_FLOW ----------------- Experimental Data ----------------- A. Experiments: The netCDF files "data_expe_mb1.nc" and "data_expe_mb2.nc" that can be found in the repository "data_expe" contain the experimental results of intense sediment transport experiments (sheet flow) carried out in the LEGI tilting flume. Synchronised and colocated concentration and veclocity (wall-normal and streamwise components) measurements have been obtained by using the Acoustic Concentration and Velocity Profiler (ACVP - Hurther et al., 2011). Details about the experimental protocol can be found in Revil-Baudard et al. (2015) and Revil-Baudard et al. (2016). As there is no sediment recirculation in the flume, the same run has been repeated several times to perform ensemble averages. As an illustration of the experiments, a movie file 'SheetFlowHiSpeedCam.mp4' can be found in the root directory of the repository. B. Data reading and display: The dataset can be read and displayed by running the python script "plot_expe.py" (requires python-2.7.9 or higher, matplotlib-2.0.0 or higher, netCDF4-1.1.7 or higher). C. Data organisation: The suffix in each netCDF file corresponds to different experimental conditions mbx, mb standing for mobile bed and "x" standing for 1 or 2 as described in Revil-Baudard et al. (2016). D. Parameters: -Vertical position vector : Z -ACVP sampling frequency : Sampl_frequ -Turbulent friction velocity : U_star -Dimensionless solid load : SolidLoad_Adim -Water flow rate : Qf -Flume slope : S0 -Particle diameter : dp -Particle density : rho_p -Number of runs : N E. Superficial average DATA: The following profiles have been averaged over the N runs and over a time window of 6s, chosen based on a flow uniformity criteria. -Streamwise velocity (superficial) : U_mean -Wall-normal velocity (superficial) : W_mean -Sediment volumetric concentration (superficial): Phi_mean -Volumetric sediment flux (superficial): FluxReal_mean -Reynolds shear stress (superficial): Shear_mean -Wall-normal turbulent intensity (superficial) : Wrms_mean -Streamwise turbulent intensity (superficial) : Urms_mean F. Intermittency function: The intermittency function corresponds to the time fraction for which the velocity is zero at a given elevation. It has been averaged over the N runs and over the same time window of 6s as the superficial DATA. -Intermittency function : Int_Func G. Averaged intrinsic DATA: The intrinsic profiles corresponds to the ensemble and temporal averaged performed by removing the zero velocity values from the original DATA. -Streamwise velocity (intrinsic) : U_mean_Int -Wall-normal velocity (intrinsic) : W_mean_Int -Reynolds shear stress (intrinsic): Shear_mean_Int -Wall-normal turbulent intensity (intrinsic) : Wrms_mean_Int -Streamwise turbulent intensity (intrinsic) : Urms_mean_Int H. References: Hurther, D., Thorne, P. D., Bricault, M., Lemmin, U., & Barnoud, J. - M. (2011) 'A multi-frequency Acoustic Concentration and Velocity Profiler (ACVP) for boundary layer measurements of fine-scale flow and sediment transport processes'. Coastal Engineering, 58, 594–605. doi: 10.1016/j.coastaleng.2011.01.006 Revil-Baudard, T., Chauchat, J., Hurther, D. and Barraud, P.-A. (2015) 'Investigation of sheet-flow processes based on novel acoustic high-resolution velocity and concentration measurements', Journal of Fluid Mechanics, 767, pp. 1–30. doi: 10.1017/jfm.2015.23 Revil-Baudard, T., Chauchat, J., Hurther, D. and Eiff, O. (2016) 'Turbulence modifications induced by the bed mobility in intense sediment-laden flows', Journal of Fluid Mechanics, 808, pp. 469–484. doi: 10.1017/jfm.2016.671 -------------- Numerical data -------------- A. Numerical simulations: The results of two-phase flow numerical simulations performed using SedFOAM-2.0 are disseminated in two formats (i) the complete openFOAM case directories can be found in the repository "data_num" (ii) NetCDF files containing the concentration, velocity, shear stress and Turbulent Kinetic Energy profiles. The repository contains different combination of intergranular stress and turbulence models: the mu(I) rheology or the kinetic theory of granular flows and mixing length or k-epsilon turbulence models. All the details concerning the numerical results and the configurations can be found in Chauchat et al. (2017a) The SedFOAM-2.0 source code is distributed under a GNU General Public License v2.0 (GNU GPL v2.0) and is available at https://github.com/SedFoam/sedfoam/releases/tag/v2.0 or on Zenodo at https://zenodo.org/record/836643#.Wc47Yoo690s with the following DOI https://doi.org/10.5281/zenodo.836643 (Chauchat et al.,2017b). B. Data reading and display: The dataset can be read, displayed and compared with experimental data by running the Python script "plot_num.py" (this script is reading the NetCDF files). A second python script is available "plot_numOF.py' that allows to plot the numerical solutions in the openFOAM format (requires the fluidfoam package freely available at http://bitbucket.org/sedfoam/fluidfoam). This option is useful if one wants to further evaluate other combinations of intergranular stress and turbulence models or test different parameter values in the model. C. Data organisation: The first suffix of the cases names describes the solid phase stress model used in the numerical simulation (MuI: the Mu(I)dense granular-flow rheology, KT: Kinetic Theory of granular flows). The second suffix describes the turbulence model used for the simulation (ML: Mixing Length, kEps: two-phase k-Epsilon model). For simulations with k-epsilon turbulence model and dense granular-flow rheology, the value of the turbulence model parameter "B" used for the calculation is also specified. This parameter is related to the drag induced turbulence dissipation in the k-epsilon model for which uncertainties remain concerning it's dependency to physical parameters such as Stokes or particulate Reynolds numbers for example. D. Numerical data: -Vertical position vector: ccy -Fluid velocity: Ub -Sediment volumetric concentration: alpha -Fluid shear-stress: Tauf (needs to be multiplied by the fluid density and the fluid volumetric concentration) -Turbulent Kinetic Energy (TKE): k H. References: Chauchat, J., Cheng, Z., Nagel, T., Bonamy, C., Hsu, T.-J. (2017a). 'Sedfoam-2.0: a 3d two-phase flow numerical model for sediment transport. Geosci. Model Dev., 10, 4367-4392, doi: 10.5194/gmd-10-4367-2017 Chauchat, J., Cheng, Z., Bonamy, C., Nagel, T., Hsu, T.-J. (2017b). SedFoam/sedfoam: Release 2.0 (Version 2.0). Zenodo. doi: 10.5281/zenodo.836643