# The physics of shaking off the water

1. Oct 21, 2009

### dymitrruta

Hi all, I just noticed that by shaking the water off my hands 3 times after using the toilet I can reduce the hand-drying time from 30 to about 20s and hence am looking for help in a proper evaluation of the following energy saving problem related to drying.

So lets stick to the same simple scenario of shaking the water off your hands after using the toilet. I am trying to evaluate how much of water excess can be shaken off by a sequence of repetitive identical shakes (same force(time) profile) to build a graph of the water mass excess as a function of the number of shakes and eventually the amount of energy required to dry as a function of the number of shakes. I understand it very much depends on the type of material and how much water penetrated inside which cannot be shaken off. Any generic ideas welcome and much appreciated.

To start with did you come across of any general equations describing dynamics of the drying process so I can figure out how the drying time depends on the initial mass of water excess?

Many thanks for any help