deletions | additions       diff --git a/Payam.tex b/Payam.tex  index 11023e7..4c26745 100644  --- a/Payam.tex  +++ b/Payam.tex 
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\item {\it Does Payam assume incompressible flow?} 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?}\\ included?}  I would have to re-derive the formulae for the submerged jet, and perhaps solve the time-dependent Navier-Stokes equation.\\  However, it would (arguably) be a better model (see references below), and may be more illuminating as to how the velocity profile is set up, and the nature of interactions between neighbouring DNA molecules.