Use the 2nd Law of Thermo to prove that the flow must go from high pressure to low pressure.?

but if you take into account that the second law of thermodynamics states that a system left alone will always experience an increase of disorder, then it does apply. a high pressure environment is a very high order one, because the particles inside are more restricted. a low pressure environment is a has a high DISorder, which follows the law of thermo.