STEP-BY-STEP INSTRUCTION FOR EXAMPLE 4

 

The sample PIV recording pair was taken in a water/solid two-phase flow experiment. The image size is 450x450 pixels. The corresponding measurement area in the laser light sheet is 82-mm x 82-mm. The time interval is 20 ms.

Step 1: Load digital PIV recording pair and phase masks

- Execute file “Edpiv.exe” - The start window is shown on the screen;

- Select menu “File \ Open recording 1” to open “…\ PIVsamples \ 4_SolidParticleWaterFlow \ 33519x.bmp”;

- Select menu “File \ Open recording 2” to open “…\ PIVsamples \ 4_SolidParticleWaterFlow \ 33520x.bmp”.

- Select menu “File \ Import mask 1” to open “…\ PIVsamples \ 4_SolidParticleWaterFlow \ mask1.bmp”;

- Select menu “File \ Import mask 2” to open “…\ PIVsamples \ 4_SolidParticleWaterFlow \  mask2.bmp”;

Step 2: Determine imaging scale and time interval

- Click menu “Edit / Scale & time” in the start window to open dialogue box “Imaging scale / time interval”;

- Select radio button mm;

- Input 82 in edit box “Reading on ruler”;

- Input 450 in edit box “Corresponding pixels”;

- Input 20000 in edit box “Time interval [mu-s]”;

- Press “OK” button to return to start window.

Step 3: Setup evaluation parameters for continuous phase

- Click menu “Edit / Evaluation settings” in the start window to open the “Evaluation settings” window;

- Setup parameters as follows
Method & algorithm:
PIV
Ellipse window: Selected
Recording type:
Single recording (pair)
Exposure type:
Single
Flow type:
Two phase
Phase type:
Continuous.
Initial window shift:
(X,Y), x=0, y=0
Interrogation grid:
8x8
Error limits:
Dx=2.0, Dy=3.0
Iteration number:
0 (Initial), 6(Final) 
Window width :
32 (Initial), 32 (Final)
Window height :
32 (Initial), 32 (Final)
Search radius:
6

- Close “Evaluation settings” window.

Step 4: Evaluate PIV recording pair for continuous phase

- Press button “Evaluation” in the start window;

- Click menu “Edit \ Grid structure \ Regular” - Window “Regular evaluation grid” appears;

- Push button “Reset grid” and then press button “OK”;

- Click menu “Start” in “Evaluation” window;

- Answer “Yes” to question “Do you want to start an evaluation?”;

- Wait until the evaluation is completed;

- Press button “OK” to close the dialogue box that notices the end of the evaluation;

- Click menu “Edit \ Save vectors into \ M1” to store the vectors in memory 1.

- Close “Evaluation” window.

Step 5: Identify solid particle positions

- Press button “Show image” to display the first recording in the pair in the picture frame;

- Press button “Processing” - “Image processing” window appears;

- Click menu “Edit \ Particle processing \ Position search #1 - Dialogue box “Particle image identification” appears;

- Setup parameters as
Minimal diameter:
10
Maximal diameter:
60
Gray value threshold:
127

- Press “OK” button to complete the particle image identification;

- Click menu “File \ Close” - Back to the start window;

Step 6: Setup evaluation parameters for the dispersed phase

- Click menu “Edit / Evaluation settings” in the start window to open the “Evaluation settings” window;

- Setup parameters as follows
Method & algorithm:
PIV
Ellipse window: Selected
Recording type:
Single recording (pair)
Exposure type:
Single
Flow type:
Two phase
Phase type:
Dispersed
Initial window shift:
(X,Y), x=0, y=0
Interrogation grid:
Ignored
Error limits:
Ignored
Iteration number:
0 (Initial), 6 (Final) 
Window width :
32 (Initial), 32 (Final)
Window height :
32 (Initial), 32 (Final)
Search radius:
12

- Close “Evaluation settings” window.

Step 7: Evaluate PIV recording pair for dispersed phase

- Press button “Evaluation” in the start window - “Evaluation” window is opened, and evaluation points are automatically selected;

- Click menu “Start” in “Evaluation” window;

- Answer “Yes” to question “Do you want to start an evaluation?”;

- Press “OK” button to close the dialogue box that notices the end of the evaluation;

Step 8: Display evaluation results on the screen

- Increase the window size to clearly see the vectors;

- Click button “P” to hide the small red crosses;

- Select menu “View \ Vectors” - Dialogue box “Display vectors” appears;

- Select M0 and M1 in the dialogue box and then close the dialogue box;

- Push down button “c” to center vectors at evaluation points;

- Press “-” and “+” buttons to adjust length of the displayed vectors.

Step 9: Save evaluation results

- Click menu “File \ Save data” to save the vector map of the dispersed phase;

- Select menu “Edit \ Load vectors from \ M1” to load vectors saved in M1;

- Click menu “File \ Save data” to save the vector map of the continues phase.

Step 10: Plot vector map

- Close EDPIV;

- Use TECPLOT to make plots.