Data and results of air trapping simulations

This technical report provides data and results in support of Lokhandwala et al. (2025), which uses the US Environmental Protection Agency Storm Water Management Model (EPA SWMM) to evaluate the initiation of air trapping between two manholes. Presented herein are data graphics of the simulation set for the entrapped air volume, $V_e^*$, against inflow bias, $\Delta Q^*$, along with metrics of $V_e^*$ against both the relative inflow, $Q_T^*$, and the entrapping flow, $Q_e^*$. Comparisons of envelope centroid metric $(\Delta Q_c^*$) of the trapped volume envelope ($V_e^*:\Delta Q^*$) show that the centroid metric is a minor contributor to trapping. Effects of manhole diameter, which are neglected in Lokhandwala et al. (2025) are explored and shown to be irrelevant for typical scales of manhole diameter to conduit diameter. Also, effects of gradual rise in inflows at both junctions are studied and the choice of using sharp inflows in the analysis of Lokhandwala et al. (2025) is justified. Note that the full test set included 15 different bottom slopes over the range $S_0 \in \left\{0.05\%, 0.10\%, 0.15\%... 0.75\% \right\}$, but reported results are limited to the set $S_0 \in \left\{ 0.10\%, 0.35\%, 0.75\% \right\}$ as the other slope cases do not provide any significant insights into behaviors.