Is Brenner's Modification to the Classical Navier--Stokes Equations Able to Describe Sound Propagation in Gases?

We analyse the problem concerning the propagation of sound waves in gases by using the modified hydrodynamic theory proposed recently by Brenner for
single-component fluids. The modifications introduced by Brenner are based on his proposal that the translational momentum in fluid motion is not given by the mass flux. Comparison of the sound propagation results derived from Brenner's theory with available experimental data for monatomic gases shows that this modified continuum theory is unable to describe the acoustic measurements not even in the low-frequency limit, a result that from our point of view makes Brenner's proposal questionable.