A cylindrical tank of water rotates about its vertical axis (Fig. P4‒78). A PIV system is used to measure the vorticity field of the flow. The measured value of vorticity in the z-direction is ‒45.4 rad/s and is constant to within ±0.5 percent everywhere that it is measured. Calculate the angular speed of rotation of the tank in rpm. Is the tank rotating clockwise or counterclockwise about the vertical axis?

Solution

Step 1 of 4

The given water tank is rotating about its vertical axis with the given vorticity along z- direction (vertical axis), here we need to calculate the angular speed of the tank in rpm using the given vorticity.