$(25-$points$)$ It takes a certain length of time for the liquid level in a tank of diameter $D$ to drop from position $h_1$ to position $h_2$ as the tank is being drained through an orifice of diameter $d$ at the bottom. Determine the $-$groups that apply to this problem. Assume that the liquid is non$-$viscous. Express your answer in the functional form:

$\frac{h}{d}=f({}_1,{}_2,{}_3)$