The discussion revolves around the state postulate for incompressible substances, particularly focusing on liquids like water and solids. Participants explore the requirements for defining the thermodynamic state of these substances and question the significance of the state postulate in various contexts.
Participants express differing views on the compressibility of liquids and the relevance of the state postulate for incompressible substances. There is no consensus on the importance of the state postulate for incompressible systems or the specific properties required to define their state.
Some participants highlight that while water is often treated as incompressible in fluid mechanics, it is fundamentally compressible, which complicates the discussion of the state postulate. The applicability of concepts like the Poynting Correction to incompressible substances remains unresolved.
Please identify what you consider an incompressible system.Signature said:State postulate for a simple compressible system is completely specified by two independent intensive properties.
But what about state postulate for a incompressible system.
Why it is not so important?
just considering only liquids specifically waterChestermiller said:Please identify what you consider an incompressible system.
Liquid water is compressible, so it still takes specification of two intensive properties to define its thermodynamic equilibrium state. See the phase diagram for water.Signature said:just considering only liquids specifically water
Chestermiller said:Liquid water is compressible, so it still takes specification of two intensive properties to define its thermodynamic equilibrium state. See the phase diagram for water.
It's certainly mentioned in thermodynamics books. Look up Poynting Correction.Signature said:Let it be, but, in most cases especially fluid mechanics we treat water as an incompressible liquid. Anyway if there is an incompressible substance, what are the basic properties which are required to completely specify its state. Why no textbooks did mention about the state postulate of incompressible substances?
I'm sure you are aware that there is no such thing as a completely incompressible liquid.Signature said:But Poynting correction is for real gases. But I want to know about incompressible substance.
Ok sir. Then what about the state postulate for solidsChestermiller said:It's certainly mentioned in thermodynamics books. Look up Poynting Correction.
Chet
How can we define the state of solidsSignature said:Ok sir. Then what about the state postulate for solids