GGU-SLUGTEST: COOPER et al. approach to the solution
For the water level in a well, COOPER et al. (1967) arrived at the following solution:

where:


and
h0 : Water level in well at time t = 0 [m]
h(t) : Water level in well at time t [m]
T : Transmissivity [m²]
S : Storage coefficient [-]
u : Integration constant [-]
f(u) :
J0,1 : Bessel functions 0th, 1st order 1st degree [-]
Y0,1 :Bessel functions 0th, 1st order 2nd degree [-]
rs : Radius of well screen [m]
rc : Radius of casing [m]
By numerical integration, COOPER et al. (1967) compiled five tables with h(t)/h0 and ß for varying