Changes between Version 48 and Version 49 of Tutorial/AdvancedParticleImagingVelocimetry2


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Timestamp:
Jan 21, 2015, 5:01:04 PM (6 years ago)
Author:
vaillant1p
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  • Tutorial/AdvancedParticleImagingVelocimetry2

    v48 v49  
    2020Select the check box Mask and open the file 'mask_1.png' previously created.
    2121
    22 Looking at the results with uvmat, we see the global flow features. We notice however that the thin parietal plume is not properly resolved while the precision in the interior is poor because of the small displacement within the frame pair. So the next step will be to perform two PIV series optimized for each sub-region and merge them.
     22Looking at the results with '''uvmat''', we see the global flow features. We notice however that the thin parietal plume is not properly resolved while the precision in the interior is poor because of the small displacement within the frame pair. So the next step will be to perform two PIV series optimized for each sub-region and merge them.
    2323
    2424= Making two masks =
    25 The parietal jet requires a very good resolution, particularly among ''x''. To limitate PIV to this jet, let us create a specific mask. Open the previously created contour polygon ''contour_mask.xml'' in '''uvmat''' by the menu bar '''Projection object/browse...'''. Check the box '''edit''' (tag '''[!CheckEditObject]''') in the frame '''Object''' of '''uvmat''' (left hand side) to allow editing of the polygon then replace the lower ''x'' bound 0 by 52. Create the corresponding mask by '''Tools/make mask''', save it with name ''Dalsa1.mask/mask_plume.png''. Similarly create a mask for the bulk ''Dalsa1.mask/mask_bulk.png'', with bounds in ''x'' [0 55].
     25The parietal jet requires a very good resolution, particularly among ''x''. To limitate PIV to this jet, let us create a specific mask. Open the previously created contour polygon ''contour_mask.xml'' in '''uvmat''' by the menu bar '''Projection object/browse...'''. Check the box '''edit''' (tag '''[!CheckEditObject]''') in the frame '''Object''' of '''uvmat''' (left hand side) to allow editing of the polygon then replace the lower ''x'' bound 0 by 52. Select the '''[SAVE]''' button to save it as a .xml figure. Create the corresponding mask by '''Tools/make mask''', save it with name ''Dalsa1.mask/mask_plume.png''. Similarly create a mask for the bulk, saving it as a .xml figure and with '''Tools/make mask''' as ''Dalsa1.mask/mask_bulk.png'', with bounds in ''x'' [0 55].
    2626
    2727= PIV on the parietal plume =
    28 Open an image of the subfolder Dalsa1.sback (for instance Dalsa1_1_1.png) and in the GUI '''series''', change the same on the bottom '''output !SubDir''' by ''Dalsa1.sback.civ_bulk''.
     28Open an image of the subfolder Dalsa1.sback (for instance Dalsa1_1_1.png) and open the GUI '''series''' to change the name at the bottom '''output !SubDir''' by ''Dalsa1.sback.civ_bulk''.
    2929
    30 Choose the following parameters in the GUI '''civ_input''':
     30Click then on 'civ_series' in the '''Action''' list to open the GUI '''civ_input'''. Choose the following parameters:
    3131
    3232 * pair j=1-2 for Civ1 and Civ2 : it minimises the time interval which is needed to capture the large velocity in the plume.
     
    4747
    4848= Merging data using thin plate spline =
    49 The previously used linear interpolation does not provide field derivatives. For that purpose, we proceed as previouisly but use the option '''[!ProjMode]=''''interp_tps' for the projection plane in '''set_object'''. To reach this GUI using the same projection object as before just select the check box '''edit''' to open the GUI '''set_object'''. Change the option '''[!ProjMode]''' and click on '''[REFRESH]'''.
     49The previously used linear interpolation does not provide field derivatives. For that purpose, we proceed as previouisly but use the option '''[!ProjMode]=''''interp_tps' for the projection plane in '''set_object'''. To reach this GUI using the same projection object as before just select the check box '''edit''' in the GUI '''series''' to open the GUI '''set_object'''. Change the option '''[!ProjMode]''' and click on '''[REFRESH]'''.
    5050
    5151In the GUI '''series''', select simultaneously the fields 'vec(U,V)', 'curl(U,V)' and 'div(U,V)' (using the keyboard Ctrl button) to get the vorticity and divergence in addition to velocity. The calculation is significantly longer that for 'interp_lin', so in the demo we use a resolution DX=DY=0.2 cm for the projection plane (instead of 0.1 cm).