why is it that for ideal fluids deformations are permanent? is this the idea of fluids filling any container i.e cannot take any shape it wants?
ncastaneda02
@ShaamerKumar pretty much! More formally, an ideal fluid has no resistance to flow. So, when you apply a stress to it, it deforms perfectly linearly with respect to the stress applied. However, unlike a perfect solid, when the stress stops, fluid cannot, on its own, revert back to its original state (like a foam cube could). Thus, the deformation is permanent. You can read more about the math here: https://geo.libretexts.org/Courses/University_of_California_Davis/GEL_056%3A_Introduction_to_Geophysics/Geophysics_is_everywhere_in_geology.../01%3A_Rheology_of_Rocks/1.05%3A_Viscous_Deformation
modatberkeley
How do we take into account surface tension? Would I be correct to assume liquids are non-ideal, since they have some viscoelasticity due to surface tension?
why is it that for ideal fluids deformations are permanent? is this the idea of fluids filling any container i.e cannot take any shape it wants?
@ShaamerKumar pretty much! More formally, an ideal fluid has no resistance to flow. So, when you apply a stress to it, it deforms perfectly linearly with respect to the stress applied. However, unlike a perfect solid, when the stress stops, fluid cannot, on its own, revert back to its original state (like a foam cube could). Thus, the deformation is permanent. You can read more about the math here: https://geo.libretexts.org/Courses/University_of_California_Davis/GEL_056%3A_Introduction_to_Geophysics/Geophysics_is_everywhere_in_geology.../01%3A_Rheology_of_Rocks/1.05%3A_Viscous_Deformation
How do we take into account surface tension? Would I be correct to assume liquids are non-ideal, since they have some viscoelasticity due to surface tension?