  Inviscid hydrodynamics mediates forces through pressure and other, typically
irrotational, external forces. Acoustically induced forces must be consistent
with arising from such a pressure field. The use of "acoustic stress" is shown
to have inconsistencies with such an analysis and generally arise from
mathematical expediency but poor overall conceptualization of such systems.
This contention is further supported by the poor agreement of experiment in
many such approaches. The notion of momentum as being an intrinsic property of
sound waves is similarly found to be paradoxical. Through an analysis that
includes viscosity and attenuation, we conclude that all acoustic streaming
must arise from vorticity introduced by viscous forces at the driver or other
solid boundaries and that calculations with acoustic stress should be replaced
with ones using a nonlinear correction to the overall pressure field.
