Peristaltic pumping
= Peristaltic pumping
<Peristaltic pumping> transports fluid by a travelling deformation or travelling external <pressure> acting on a tube. With wave coordinate $X=x-ct$, <mass conservation> makes the relative flux $Q=\alpha(u-c)$ constant. The laboratory flux is $\alpha u=c\alpha+Q$, so a negative relative flux does not rule out forward mean pumping.