Step 9: Postprocessing

  You will now examine the progress of the sand and water in the mixing tank after a total of 20 seconds. The mixing tank has nearly, but not quite, reached a steady flow solution.

1.   Display the velocity vectors for water (Figure  21.12).

Graphics and Animations Vectors Set Up...

  Figure  21.12 shows the water velocity vectors after 20 seconds of operation. The circulation of water is now very strong in the lower portion of the tank, though modest near the top.

Figure 21.12: Water Velocity Vectors after 20 s

2.   Display the velocity vectors for sand (Figure  21.13).

Graphics and Animations Vectors Set Up...

  Figure  21.13 shows the sand velocity vectors after 20 seconds of operation. The sand has now been suspended much higher within the mixing tank, but does not reach the upper region of the tank. The water velocity in that region is not sufficient to overcome the gravity force on the sand particles.

Figure 21.13: Sand Velocity Vectors after 20 s

3.   Display contours of sand volume fraction (Figure  21.14).

Graphics and Animations Contours Set Up...

Figure 21.14: Contours of Sand Volume Fraction after 20 s

4.   Display filled contours of static pressure for the mixture (Figure  21.15).

Graphics and Animations Contours Set Up...

(a)   Select mixture from the Phase drop-down list.

(b)   Select Pressure... and Static Pressure from the Contours of drop-down lists.

(c)   Click Display and close the Contours dialog box.

  Figure  21.15 shows the pressure distribution after 20 seconds of operation. The pressure field represents the hydrostatic pressure except for some slight deviations due to the flow of the impeller near the bottom of the tank.

Figure 21.15: Contours of Pressure after 20 s