  Recently, the phenomena of streaming suppression and relocation of
inhomogeneous miscible fluids under acoustic fields were explained using the
hypothesis on mean Eulerian pressure. In this letter, we show that this
hypothesis is unsound and any assumption on mean Eulerian pressure is needless.
We present a theory of non-linear acoustics for inhomogeneous fluids from the
first principles, which explains streaming suppression and acoustic relocation
in both miscible and immiscible inhomogeneous fluids inside a microchannel.
This theory predicts the relocation of higher impedance fluids to pressure
nodes of the standing wave, which agrees with the recent experiments.
