Case # | Description | Provider | Image type | Number of sets | Size |
---|---|---|---|---|---|
A | Strong vortex | Kaehler | real | 1 | 1280 x 1024 |
B | Strong vortex with different seeding concentration (high, medium, low) and different particle image size (two) | Okamoto | synthetic | 6 | 512 x 512 |
C | Strong wall reflection in an impeller (background images and mask are provided) | Stanislas | real | 1 + 2 bg + 1 msk | 1K x 512 |
E | Different velocity gradients with spatially varying image quality | Okamoto | synthetic | 6 | 256 x 128 |
---------------------------------------------------------------------------- Instructions for the analysis of case A : Loss of seeding in the core of a tip vortex 26.10.2000 christian.kaehler@dlr.de Image A001_1.tif and A001_2.tif were recorded at the DNW-LLF in order to study experimentally the wake vortex formation behind a transport aircraft (DLR ALVAST half model) in landing configuration (U=60 m/s, main flow direction is perpendicular to the light-sheet plane). The measurement position was 1.64 m behind the wing tip and the field of view is 170 mm by 140 mm. The images were selected as strong gradients, loss of image density, and varying particle image sizes are common problems for many PIV applications in large wind tunnels. Camera characteristics: Type PCO SensiCam, see http://www.pco.de Sensor technology Progressive Scan Resolution 1280 pixel x1024 pixel. Pixel size 6.7 micrometer x 6.7 micrometer Dynamic range 12 bits (Peltier cooled) Quantum efficiency typ 40 % Full well capacity 25000 e Readout noise @ 12.5MHz 7 ... 8 e
Instructions for the analysis of case C : Strong wall reflection 28/10/00 contact : Pr Stanislas pivnet-sig32@univ-lille1.fr The set of images is referenced C001_1.tif and C001_2.tif. Their size is 1000 x 512 pixel. They are provided in tif format with a header of 8 pixels. These images were recorded in a centrifugal impeller with a pulsed YAG laser (about 300 mJ/pulse) and PEG smoke (about 1 micron in diameter). They are selected for the strong reflection occurring on the trailing edge of the blade. The black line going across the field from bottom right to top left is a shadow used to limit the flare on the trailing edge. The two white circles are the two edges of the fixed vaneless diffuser. Camera characteristics Type KODAK ES1.0 b & w Resolution 1008x1018 pixels. Framing rate 30 frames/s. Image capture Progressive Scan, full frame. asynchronous reset. single or double exposure. CCD size 9,072 x 9,162 mm. Pixel size 9micro-m x 9micro-m. Image coding 8 bits. Gamma 1. Exposure time In double exposure mode: 255 micro-s for image 1. 32.436 ms for image 2. Lens Nikkor 35 mm f/2. Acquisition software INSIGHT 2.10. Together with the PIV images are provided 2 background images named Cbg_1.tif and Cbg_2.tif in the same format. These images were obtained in the same experimental conditions, just by cutting of the seeding. Also provided is 1 mask named Cmask_1.tif, in the form of a binary image, corresponding to the obstacles present in the image. The measurement points inside the black mask should have a value of 0 in the velocity matrix and in the flag matrix. The reference analysis for this case is : :ev_IS_size_x = 32; :ev_IS_size_y = 32; :ev_IS_size_unit = "pixel"; :ev_IS_grid_distance_x = 16; :ev_IS_grid_distance_y = 16; :ev_IS_grid_distance_unit = "pixel"; :ev_origin_of_evaluation = 16, 16; :ev_origin_of_evaluation_units = "pixel"; :ev_IS_offset = 0, 0; :ev_IS_offset_units = "pixel"; :ev_CF_xy_distortion = 1.0 ; :ev_cf_fill_ratio = 0.6; The mandatory data to be provided are : Raw data : C001_team_ref_raw.nc - the raw velocity field corresponding to the highest correlation peak outside the mask (raw) - the corresponding histogram , - 4 samples of correlation windows at x (pixels) y (pixels) 624 256 288 352 160 160 896 432 - a matrix of correlation peak height - the type of processor used - the processing time per velocity vector Post processed data : C001_team_ref_clean.nc - the post-processed velocity fields without interpolation and/or filtering with the corresponding histogram (clean), - a flag matrix giving the location of spurious vectors and holes - a matrix of correlation peak height - the mean velocity over the map outside the mask (Umean, Vmean) - the standard deviation over the map outside the mask (u', v') - the total number of valid vectors - the type of processor used - the processing time per velocity vector. Interpolated data : Interpolated velocity map is optional for this set.
The reference analysis for this case is : :ev_IS_size_x = 16; :ev_IS_size_y = 16; :ev_IS_size_unit = "pixel"; :ev_IS_grid_distance_x = 8; :ev_IS_grid_distance_y = 8; :ev_IS_grid_distance_unit = "pixel"; :ev_origin_of_evaluation = 8, 8; :ev_origin_of_evaluation_units = "pixel"; :ev_IS_offset = 0, 0; :ev_IS_offset_units = "pixel"; :ev_cf_fill_ratio = 0.7; The mandatory data to be provided are : Raw data : E00?_team_ref_raw.nc - the raw velocity field corresponding to the highest correlation peak outside the mask (raw) - the corresponding histogram , - 3 samples of correlation windows at x(pixels) y(pixels) 32 32 32 64 32 96 - a matrix of correlation peak height - the type of processor used - the processing time per velocity vector - Velocity distribution on the following vertical line x = 64 x = 160 x = 208 x = 224 - Velocity distribution on the following horizontal line y = 64 Post processed data : B00?_team_ref_clean.nc - the post-processed velocity fields without interpolation and/or filtering with the corresponding histogram (clean), - a flag matrix giving the location of spurious vectors and holes - a matrix of correlation peak height - the mean velocity over the map (Umean, Vmean) - the standard deviation over the map (u', v') - the total number of valid vectors - the type of processor used - Velocity distribution on the following vertical line x = 64 x = 160 x = 208 x = 224 - Velocity distribution on the following horizontal line y = 64 Interpolated data : Interpolated velocity map is optional for this set.