Changes between Version 12 and Version 13 of Tutorial/ComparaisonNumSolution

Timestamp:

Mar 17, 2015, 4:22:36 PM (10 years ago)

Author:

vaillant1p

Comment:

--

Tutorial/ComparaisonNumSolution

@@ -13 +13 @@
 Then '''[Open]''' one of the vector files (.civ) created. We need to substract the numerical solution to this image in order to keep only the errors between our calculation and the theorical one. Select the mall red square'''[!SubField]''' under the '''[Input]''' table to open a second file in '''uvmat'''. Open the netcdf file of the synthetic solution 'a3b_sol_num.nc'. The GUI '''get_field''' pops up, select 'vectors' in the '''[!FieldOptions]''' table and 'U' and 'V' in the right and left tables under '''[Ordinate]'''. The '''[Coordinates]''' should still remain as 'X' and 'Y'. Click on '''[OK]'''. An 'ERROR' window pops up, select '''[OK]''' and close the GUI '''set_object]''' which automatically popped up.
 
-On the left hand side of '''uvmat''' select the '''[Tranform]''' function 'diff_vel'. If this one does not appear on the list, click on 'more...' and select 'diff_vel.m' from the folder 'UVMAT/transform_field'. The difference between the two vectors should run automatically and the result appears in '''uvmat'''. Selecting '''[<-]''' and '''[+>]''' we can go through all the series observing the difference result on screen. A single file will be easier to observe the errors between the analytic and synthetic solutions. As we do not want to focus on the borders of the images we are going to create a '''[Projection object/rectangle]''' of '''[Max]''' (100, 100) with a center at x=128 and y=128. You can change this parameters once you drew the rectangle in '''set_object'''.
+On the left hand side of '''uvmat''' select the '''[Tranform]''' function 'diff_vel'. If this one does not appear on the list, click on 'more...' and select 'diff_vel.m' from the folder 'UVMAT/transform_field'. A window will pop up asking about a scale factor for the second field, keep the default factor '1' and select '''[OK]'''. The difference between the two vectors should run automatically and the result appears in '''uvmat'''. Selecting '''[<-]''' and '''[+>]''' we can go through all the series observing the difference result on screen. A single file will be easier to observe the errors between the analytic and synthetic solutions. As we do not want to focus on the borders of the images we are going to create a '''[Projection object/rectangle]''' of '''[Max]''' (100, 100) with a center at x=128 and y=128. You can change these parameters once you drew the rectangle in '''set_object'''.
 
 Then in order to obtain a single result file, go to '''series''' ('''[RUN/field series]'''). The two files should appear in the '''[Input Files]''' table. Select the '''[Action]''' function 'aver_stat'. A 'WARNING' window pops up ask you if you want to use a projection object, select '''[OK]''', the rectangle newly created should appear on the left hand corner under '''[Projection Object]'''. Another 'INPUT_TXT' window pops up to set the bin size for the histograms, enter '0.005' instead of 'auto' and select '''[OK]'''. Make sure that the i indices go from 1 to 41, that the '''[Field Transform]''' on the left hand side is 'diff_vel' and that the '''[!VelType]''' in '''[Fields]''' (right hand side) is 'civ1' instead of '*'. It is possible to change the name of the file under '''[output !SubDir]''', otherwise '''[RUN]''' the calculation.
@@ -44 +44 @@
 
 
+== Adding an increment 'dt' in the PIV ==
+In the folder '!AnalyticFlows', select one of the images from the 'a6b' series. It shows a vortex flow. In this part we are going to using the '''deformation''' CIV2 function and observe its effect on the calculations. To beginning with '''[RUN]''' a PIV on the images series only using '''[CIV2]''', '''[FIX2]''' and '''[PATCH2]''' with the default parameters.
+Then '''[Open]''' one of the vector files (.civ) created and substract it with the synthetic solution 'a6b_sol_num.nc' as in the first part of this tutorial. 
 
+Create a '''[Projection object/ellipse]''' of radius (50, 50) with a center at x=128 and y=128. You can change these parameters in '''set_object'''.
+
+Finally '''[RUN/field series]''' with the '''aver_stat [Action]''' function and the '''[Projection Object]''' as before.
+
+Now, '''[RUN]''' again the exact same PIV and select the '''deformation''' checkbox in '''[CIV2]'''. The calculation should take more time. Create the '''aver_stat''' field as well using the same projection object.
+
+You now have the fields of the image series with and without '''deformation''' for dt = 1 (default parameter).
+Do the same calculations by selecting different values of '''[Di___:dt___]''' in '''[Pair Indices]''' on the top part of '''civ_series'''.
+
+You will then be able to use the '.stat' fields to compare the effect of the '''deformation''' function in CIV2. The figure below shows the RMS, !FirstCentile, !FirstDecile, !LastDecile and !LastCentile of PIV calculations with different values of '''[Di___:dt___]''', with and without (=sans) '''deformation'''.
+
+