Solution (source code)

= Solution

The unstressed shape has equal radii at $x=\pm L$, so its contributions cancel when subtracting the elastic end pressures. The <pressure> difference is therefore
$$
\boxed{\Delta p=\alpha\frac{2Q}{U}\,[H(-\widetilde L)-H(\widetilde L)]}.
$$
The multiplier is a <pressure> scale: $\alpha$ has dimensions <pressure> per length and $2Q/U$ is a length.