Similarly, the effect of changes to operating mass flow rate (i.e., throat Reynolds number—see Table 3) is also catered for by the Stokes number (circle, plus, diamond symbols). For example, we see a large difference in capture efficiency by the midspan geometry for a particle with a Reynolds number of 75 across the three throat Reynolds numbers: 43%, 71%, and 93% for Re_{th} = 123,520, 141,426, and 176,480, respectively. The particle diameters used in each case were 7.6 *μ*m, 6.6 *μ*m, and 5.3 *μ*m, respectively. It is interesting to note that the capture efficiency is greater for the case with the lower throat Reynolds number, despite the throat velocity in this case being the smallest. Since particle Reynolds number is designed to be the same for each particle at the throat, we attribute this difference to the large difference in flow pressure in the rest of the domain (see Table 3). This would result in a larger flow density hence greater drag force at the same drag coefficient and relative velocity, which would decrease the particle response time, therefore leading to few particle-vane interactions. This highlights the importance of flow density in achieving dynamic similarity in rig scale tests and illustrates how generalized Stokes number can be used as a matching parameter to “correct” this effect.