Source number counts of submillimeter galaxies in the FLAMINGO (solid blue), TNG300 (dashed orange), TNG100 (dash-dotted green), and EAGLE (dotted pink) simulations. Shaded regions show 1σ errors for 100 realizations of the modeled submillimeter galaxy population, as discussed in Section 3.2.1. The top panel shows predictions using the L21 relation while the bottom panel uses the H13 relation. For comparison, we have overlaid observed source number counts in gray color, which are grouped as JCMT (Casey et al. 2013; Geach et al. 2017; Zavala et al. 2017; Simpson et al. 2019; Shim et al. 2020; Garratt et al. 2023; Hyun et al. 2023; Zeng et al. 2024) and ALMA (Hatsukade et al. 2013; Karim et al. 2013; Simpson et al. 2015, 2020; Fujimoto et al. 2016; Hatsukade et al. 2018; Stach et al. 2018) according to the observing facility used. We have scaled all the flux densities of ALMA bands to the S₈₅₀ band assuming a modified black body. The FLAMINGO predicts the observed number counts quite well for the H13 relation. (See Section 4.2 for more detail).