deletions | additions       diff --git a/Payam & DNA.tex b/Payam & DNA.tex  index 12173b2..ec6e363 100644  --- a/Payam & DNA.tex  +++ b/Payam & DNA.tex 
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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 in  the form of momentum flux tensor. Time doesn't enter into  the stress tensor: no time component. analysis; nor does Navier-Stokes.  \item {\it Does Payam assume incompressible flow?} 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. \item {\it Should I re-visit the derivation with sound included?}  Method 1: I would have to derive the formulae for the submerged jet in a compressible fluid, and perhaps solve the time-dependent Navier-Stokes equation.\\