Help with Transient setup

[Blackphoenixz 0]

Hello

I have a problem with understanding the exact working system of number of time steps & multiplier when you want set a setting.

for example whats different of the time you have 3 time steps and 4 multiplier instead of 1 time step and 1 multiplier?

[Michal 0]

Hi, it is actually quite simple. Each stress period is divided into one or more time steps. The time steps within a stress period does not have to be the same length, but can increase exponentialy in length in order to capture system response to change in stress more accurately. So by specifying a multiplier f, each following step is f multiple of the previous step. So if you have stress period of lets say 10 days and you want to solve it in 3 time steps with 4.0 as multiplier, modflow would calculate the following step lengths:
 {0.47619, 1.90476, 7.61905}

It is not so hard to figure the realtion as for timesteps 0 to n:
step_length_i=(perlen*f^i)/Sum[f^i, {i, 0, n - 1}]