Evolution of core (Ω_c) and surface rotation (Ω_s) rates. Four of the models listed in Table 1 are shown here, and compared to asteroseismically obtained rotation rates. The observational data points are the core (red diamonds) and the surface (orange stars) rotation rates, taken from Mosser et al. (2012), Deheuvels et al. (2012, 2014, 2015), Ceillier et al. (2017), and the compilation of observed main-sequence stars from 12 other papers presented in Aerts et al. (2017). From these observational studies, we only select single stars in the mass range 1.4−3.0 M_⊙. Typical error bars of these observations are of the order of the symbol size used. The solid and dot-dashed show the core rotation rates of the models with and without the additional viscosity respectively. The dashed lines show the envelope rotation rates of the models. The thick line segments correspond to the core burning phases, and the thin segments to the shell burning phases. The black dots indicate the time spend in the core He burning phase by the models with ν_add ≠ 0, each spaced by 10% of the total duration starting at the 10% mark and ending with the 100% mark (the dots located on the most left and right, respectively). These dots show that these models spend most of their time during this evolutionary phase close to the observed rotation rates.