This image group consists of 100 pairs of PIV recordings taken in the entrance of a microchannel of 200 micrometers in width. The fluorescent polystyrene particles used for the present experiment have a peak wavelength of 542 nm for excitation and 612 nm for emission. The diameter and density of the particles are 1 micrometer and 1050 kg/m^3, respectively. The pulsed laser beam is generated by a double cavity Nd:YAG  laser, delivered into an inverted epi-fluorescent microscope through a beam expander assembly. The light is guided to the flow field of the microchannel through a set of lens inside the microscope and a 20X objective lens. The fluorescent particles suspended in the flow field absorb the illuminating light of λ=532nm (green) and emit light with a longer wavelength (λ~610nm, red), which passes through the fluorescent filter cube into a CCD camera with a digital resolution of 1024x1280 pixels. In the focal plane, the corresponding measurement area is 348.3x435.4 square micrometer. Note that the sample recording pairs are only small portions of the original recordings.

Step 1: Generate image file list

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

- Select menu “Edit \ File list” - Dialogue box “Creating file list” appears;

- Press “Input files” button - Dialogue box “Data file list” appears;

- Browse hard drives to find folder “…\ PIVsamples \ 7_MicroChannelFlow\ ”;

- Arbitrarily select one of the Windows Bitmap (BMP) files, and then press “Open” button;

- Press “Output file” button - Dialogue box “Data file list” appears again;

- Browse the hard drives to find a desired destination folder;

- Type a name for the file list in the edit box indicated by “File name”, and then click “Save” button;

- Set “Recording type” to “2”;

- Click menu “Create” to generate the image file list;

- Close the dialogue box to return to the start window.

Step 2: Open PIV image group

- Click menu “File \ Image group” - Dialogue box “Recording group” appears;

- Browse the file system to find the image file-list created in step 1;

- Click “Open” - The first image of the first pair is shown in the picture frame.

Step 3: 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 0.3483 in edit box “Reading on ruler”;

- Input 1024 in edit box “Corresponding pixels”;

- Input 500 in edit box “Time interval [mu-s]”;

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

Step 4: Setup evaluation parameters

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

- Setup parameters as follows
Method & algorithm:
Ellipse window: Selected
Recording mode:
Recording group: ensemble evaluation
Exposure type:
Flow type:
One phase
Initial window shift: (X,Y), X=9, Y=0
Interrogation grid:
Error limits:
Dx=3, Dy=1.5
Iteration number:
0 (Initial), 6 (Final) 
Window width :
64 (Initial), 32 (Final)
Window height :
64 (Initial), 32 (Final)
Search radius:

- Click menu “Image filter” to select
Digital image filter:
Filter: w=
11 , h= 11

- Close “Evaluation settings” window.

Step 5: Evaluate the PIV recording pairs

- Press button “Evaluation” in the start window - “Evaluation” window is opened, and a regular interrogation grid is ready;

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

- Answer “Yes” 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.

Step 6: Save evaluation results

- Click menu “File \ Save data” - Dialogue box “Save evaluation results” appears;

- Find a desired folder, type in a file name in the dialogue box;

- Press button “Save” to complete the saving procedure.

Step 7: Plot vector map

- Close EDPIV;

- Use TECPLOT to make plots.