longitudinal charge conductivity can be measured in experiments with surface acoustic waves (SAWs) [@Ingebrigtsen1969; @Simon1996; @Efros1990; @Wixforth1989; @Rotter1998; @Govorov2000]. The transverse conductivity determines the skin effect, which is however not a feasible measurement for a two-dimensional graphene sheet. In section \[sec:Surface-acoustic-waves\] we consider a simple device consisting of a graphene sheet laid on top of a piezoelectric crystal. We calculate the velocity shift and damping of SAWs induced by the graphene sheet and find that, while damping effects are small, a substantial velocity shift can be expected. The damping and the velocity shift measured as functions of temperature can give important insights into the nature interaction effects in a Dirac fluid.

Non-local transport coefficients also determine in confined geometries. The latter case is illustrated in Sec. \[sec:Poiseuille-profiles\] for the electric conductivity, using the Poiseuille geometry as an example. The constitutive relation linking the electric current to the electric field along the channel is interpreted as a differential equation (Eq. (\[eq:pois\_el\_diff\])) and solved with the appropriate boundary conditions (Eq. (\[eq:boundary\_condition\_nl\])). We find, that the flow profiles strongly depend on the channel width $w$ as compared to the electron-electron scattering lengths in the $m=1$ and $m=2$ channels: $l_{c,1}=v\tau_{c,1}$, $l_{c,2}=v\tau_{c,2}$. While $l_{c,1}$ governs 