Glass viscosity calculations debunk the myth of flow in medieval windows (2017)

Re:Glass viscosity calculations debunk the myth of flow in m... by pfdietz on Thursday October 29, 2020 @11:10PM (#24938739)

Let's look up a definition.

"Compression: decrease in volume of any object or substance resulting from applied stress."

Compression refers to a reduction in volume, not an increase in pressure. This is finite for gas crossing a shock, even as the mach number goes to infinity.

[ Parent | on HN ]

Re:Glass viscosity calculations debunk the myth of flow in m... by bernulli on Friday October 30, 2020 @06:08PM (#24947338)

Exactly. There's no mention at all about the foundation of all your arguments, namely that compression be inherently isentropic. It simply is not. You can add it as an additional constraint, if you want to.

What I say is that even when dV approaches a constant, the pressure still rises, so the product also rises.

[edit: removed snark]

[ Parent | on HN ]

Re:Glass viscosity calculations debunk the myth of flow in m... by pfdietz on Saturday October 31, 2020 @08:47AM (#24950987)

Requiring compression to be isentropic is just requiring "compression" to be a well-defined term with a specific quantitative result. Otherwise, it's a vague term that offers no quantitative prediction for how much heating it produces for a given change in density. That's not science.

[ Parent | on HN ]