)a cylindrical tank of radius 5 m, height of 100 m and a pressure maintained at 1 atm at the top is filled with spherical, non-porous catalyst particles of radius 3 cm stored under hexane to prevent moisture absorption before use. however, the tank recently sprung a small leak on the side near the bottom. assuming the tank is tall, the fluid height does not change significantly in the span of seconds, but the superficial fluid velocity may be high. using this information, it is desired to calculate the superficial fluid velocity to determine the rate that the tank is leaking, assuming the tank behaves like a packed bed.