Presentation is loading. Please wait.

Presentation is loading. Please wait.

Dispersion within Emergent Vegetation Using PIV and Concentration Measurements Uri Shavit Technion, Haifa, Israel.

Similar presentations


Presentation on theme: "Dispersion within Emergent Vegetation Using PIV and Concentration Measurements Uri Shavit Technion, Haifa, Israel."— Presentation transcript:

1 Dispersion within Emergent Vegetation Using PIV and Concentration Measurements Uri Shavit Technion, Haifa, Israel

2 The advective dispersive equation The local (micro-scale) transport equation - Flow rate - Cross – section area

3 1.Fickian dispersion (Concentration only) 2.Decomposition and averaging (Euler) ( Simultaneous concentration & velocity) 3.Ensemble of path-lines (Lagrange) (Velocity only) We examine the PIV ability to measure dispersion, applying the following three methods:

4 The Experimental Setup

5 The experimental setup:

6 Visualization The experimental challenge is to measure simultaneously concentration & velocity.

7 Image Pair (1) (Visualization and conc. measurements)

8 Image Pair (2) (Velocimetry)

9 Experimental Conditions

10 whereis the injection discharge 1. Fickian Dispersion

11 Time-averaged normalized concentration (following an intensive calibration). Q/A=4.58cm/s, d= 3.5%. Fickian Dispersion D [cm 2 /s]

12 2. Decomposition and double averaging of the convective equation (Eulerian) Requires simultaneous measurements of velocity and concentration

13 Decomposition x y Flow Considering the commutativity rules:

14 The averaging end result: 0 The dispersion term

15 Q=66 min -1, Array Density = 3.5% 50mm Lens Y(cm) X(cm)

16 200mm Lens Y(cm) X(cm)

17

18

19 Spatial variations LongitudinalLateral Temporal fluctuations The calculated dispersion coefficient x y Flow

20

21

22 3. An Ensemble of Path-lines (a Lagrangian approach)

23 The location of a particle released at (x 0, y 0 ) at time t 0 is, Kundu, 1990, p. 324 or Williamson (1996) The Strouhal number:

24 Lateral dispersion is then calculated using the mean square of the lateral variations, Where Y is:

25 Q=66 min -1, Array Density = 3.5%50mm Lens, Y(cm) X(cm) The Evolution of Pathlines

26 The Results of the Lagrangian Approach:

27 The dispersion coefficient d = 3.5%

28

29 4 cm A Moving Frame of Reference: Q = 23 min -1, Array Density = 3.5%

30 Acknowledgments: The Israel Science Foundation (ISF) Grand Water Research Institute Joseph & Edith Fischer Career Development Chair Tuval Brandon Mordechai Amir Ravid Rosenzweig


Download ppt "Dispersion within Emergent Vegetation Using PIV and Concentration Measurements Uri Shavit Technion, Haifa, Israel."

Similar presentations


Ads by Google