Cato edited Payam and DNA.tex  almost 11 years ago

Commit id: f30018d2fb207ef2c2bf92ab5e891c9330bb3ec9

deletions | additions      

       

I want to think about {\it which time scale is more appropriate in this context and why?}  \item So, {\it what should the time-scale be from }physical {\it reasoning: what is the physics behind establishing the flow profile $\vec{v}(\vec{x})$ in the fluid around the DNA/jet?}\\  \citet{1959flme.book.....L} argue $\vec{v}(\vec{x})$ purely from momentum conservation / Gauss' Law, and symmetries of the momentum flux tensor. Time plays no role. role because the source of the momentum is static with respect to the (``Eulerian'') fluid. Can we do the same analysis with a {\it moving} submerged jet?  \item {\it Does Payam assume incompressible fluid?} Yes -- he follows \citet{1959flme.book.....L} pp. 86-88 in setting up the submerged jet; they assume zero divergence in the velocity field \& use stress tensor for incompressible flow. (The derivation in \citet{Broman_Rudenko_2010} also assumes incompressibility.) This means that the sound speed in his model will be infinite, and sonic information transfer will be irrelevant.