===== 3D backward-facing step flow at $Re_H= 6000$ ===== **Author** : Y. Fraigneau, LISN, UMR CNRS 9015 (yann.fraigneau@lisn.fr) \\ **Date** : August 2018\\ **Simulation type** : DNS (code Sunfluidh [[https://sunfluidh.lisn.upsaclay.fr|Sunfluidh code]]) \\ **Location** : DATABASE_BACKWARDFACINGSTEPFLOW_RE6000_DNS \\ ** Status ** : Restricted access \\ **Data size** : ~ 4.4 Tb \\ {{:datasetmeca:bfs_snap3000_isoq_ux.png?1000|}} \\ [[https://sunfluidh.lisn.upsaclay.fr/doku.php?id=sunfluidh:sunfluidh_gallery| A video is available here ]] \\ [[:start|Come back to first page]] ----- ==== Simulation settings ==== ---- === 2D sketch === {{ :datasetmeca:bfs_sketch.jpg?800 |}} === Referential : cartesian geometry === - axes : * x(i) : downstream direction * y(j) : normal direction * z(k) : spanwise direction - origin : * $x_0= 0$ : the step * $y_0= 0$ : the bottom wall of the domain * $z_0= 0$ : the left side of the computational domain === Reference scales === * Density : mass density of the fluid ($\rho_0$) * Length : step height ($H$) * Velocity : inlet bulk velocity ($U_i$) * Dynamic viscosity : dynamic viscosity of the fluid ($\mu_0$) * Reynolds number : $Re_H= \frac{\rho_0.U_i.H}{\mu_0}= 6000$ === Non-dimensionalised data === * velocity : $U^*=\frac{U}{U_i}$ * density : $\rho^*= \rho/\rho_0= 1$ * coordinates : $x*=\frac{x}{H}$, $y^*=\frac{y}{H}$ , $z^*=\frac{z}{H}$ === Computational domain === - **Domain scope** * Downstream direction(x) : $L^*= 36.0$ * Normal direction (y) : $H_t^*= 2.0$ * Spanwise direction (z) : $l^*= 2\pi$ * Step position : $L_s^*= 12.0$ * Step height : $H^*= 1$ - **Boundary conditions** * Inlet : Uniform profile at $X_{in}^*= -12.0$ * Outlet : Orlansky's type at $X_{out}^*= 24.0$ * Wall conditions : Top and low walls of the domain * Periodicity : lateral ends of the domain - **Domain decomposition (160 MPI subdomains)** * Along the downstream direction : * 12 (between the inlet and the outlet, above the step) * 8 (between the step and the outlet) * Along the normal direction : 4 * Along the spanwise direction : 4 * 2D sketch of domain decomposition in a plan {xy} (MPI process distribution (1)) \\ 1 1 1 1 1 1 1 1 1 1 1 1 \\ 1 1 1 1 1 1 1 1 1 1 1 1 \\ 0 0 0 0 1 1 1 1 1 1 1 1 \\ 0 0 0 0 1 1 1 1 1 1 1 1 \\ - **Spatial resolution** : * Grid : $128 \times 64 \times 64$ per subdomain (83.886.080 cells over the domain) * About cell-size * $\Delta x_{min}^*= 1.0 \, 10^{-3} \quad \Delta x_{max}^*= 2.456 \,10^{-2}$ (downstream direction) * $\Delta y_{min}^*= 1.1 \, 10^{-3} \quad \Delta y_{max}^*= 1.653 \,10^{-2}$ (normal direction) * $\Delta z_{min}^*=\Delta z_{max}^*= 2.4543 \, 10^{-3}$ (spanwise direction) [[:start|Come back to first page]] ---- ==== Data features ==== ---- * **Time series from probes** * Physical quantities : velocity components along x, y and z directions (u,v,w) and pressure (p) * 11 probes * Time step= 0.01 time unit * Time range : 200.0 to 513.3 time units * Locations (In vertical plan at $z=3.14$) * Xi=-4.00 , Xj= 1.50 , Xk= 3.14 - MPI Subdomain ID : 17 * Xi=-2.00 , Xj= 1.50 , Xk= 3.14 - MPI Subdomain ID : 25 * Xi= 0.10 , Xj= 1.00 , Xk= 3.14 - MPI Subdomain ID : 37 * Xi= 4.00 , Xj= 1.00 , Xk= 3.14 - MPI Subdomain ID : 53 * Xi= 4.00 , Xj= 0.01 , Xk= 3.14 - MPI Subdomain ID : 49 * Xi= 6.00 , Xj= 1.00 , Xk= 3.14 - MPI Subdomain ID : 69 * Xi= 6.00 , Xj= 0.01 , Xk= 3.14 - MPI Subdomain ID : 65 * Xi= 8.00 , Xj= 1.00 , Xk= 3.14 - MPI Subdomain ID : 69 * Xi= 8.00 , Xj= 0.01 , Xk= 3.14 - MPI Subdomain ID : 65 * Xi=16.0 , Xj= 1.00 , Xk= 3.14 - MPI Subdomain ID : 117 * Xi=16.0 , Xj= 0.01 , Xk= 3.14 - MPI Subdomain ID : 113 * File name (per physical quantity) : x_ins_yyyyy.d with x= u,v,w,p and 'yyyyy' the MPI subdomain ID * **3D snapshots** * Instantaneous fields : velocity components in x, y and z directions (U,V,W) and pressure (P) * Recording rate : 0.1 time unit * Time range from from 185.3 to 513.3 time units * File name : res_xxxxx_yyyyyyy.d (xxxxx : MPI subdomain ID, yyyyyyy : Time ID) * MPI subdomain ID: from 0 to 159 * Time ID : from 186 to 3465 * **Statistics** * fields : (i,j : indexes of direction x, y or z) * Mean fields of velocity components () and pressure (

) * Mean fields of quadratic quantities (, ) * Time and space average computation (along the spanwise direction) * Time startup = 180.0 time units * Time range per file = 10.0 time units * Total time range from 180.0 to 510.0 time units * file name : rst_xxxxx_yyyyyyy.d (xxxxx : MPI subdomain ID, yyyyyyy : Time ID) * MPI subdomain ID : from 0 to 39 (MPI process rank where results about space average computation are stored) * Time ID : from 1 to 33 [[:start|Come back to first page]] ---- ==== Database organisation ==== ---- **Data size** : ~ 4.4 Tb \\ **Main directory** : /vol/DATABASE_MECA/RESTRICTED_ACCESS/DATABASE_BACKFACINGSTEPFLOW_RE6000_DNS \\ For more details about files, see the [[https://sunfluidh.limsi.fr| wiki doc of Sunfluidh]] === Directories & files === /GRID : contains all ASCII files about grid setup input data file : data_meshgen.d report on grid features : report_meshgen.d grid files for sunfluidh: maillx.d, mailly.d, maillz.d check files (ASCII) : check_mesh_I.d,check_mesh_J.d,check_mesh_K.d (3 columns : indices, cell-face coordinates, cell size) /DATASETUP : ASCII files input data file for sunfluidh : input3d.dat data file for MPI subdomain distribution (MPI graphical topology): data_mpi_subdomain_layout.dat /TIMESERIES : contains time series recorded over the time range [200,513.3] ASCII files : x_ins_yyyyy.d with x= u,v,w,p time series files are sliced in directories CAS-MPI160-n (n from 121 to 330) WARNING : possible underlying of time series for these data couples : n = (243,244) n = (246,247) n = (259,260) n = (260-261) The directory CAS-MPI160-260 contains 2 groups of consecutive timeseries files placed in directories DIR-A and DIR-B /SNAPSHOTS : snapshots binary files res_xxxxx_yyyyyyy.d files stored in archive files : res_yyyyyyy.tar for each time ID /STATISTICS : statistics binary files files rst_xxxxx_yyyyyyy.d files stored in archive files : rst_z.tar , z is an ID number /RESTART_AR : backup/restart archive save.tar at 513.27 time units [[:start|Come back to first page]]