This paper is a survey article on some recent results obtained by the authors in the field of gas flows through porous media described by the Darcy law and flows of inviscid gases described by Euler equations. We explicitly formulate thermodynamics in terms of contact and symplectic geometry and show the link between thermodynamics and measurement theory. The methods provided by the geometrical reformulation of thermodynamics are applied to analysis of various models of real gases, special attention is paid to phase transitions. We provide explicit methods of finding solutions for the Dirichlet filtration problem and Euler flows and show how thermodynamics of gases under consideration emerges along the gas flow. In particular, we find the locations for different phases of the medium.