Second-order velocity structure function of Oph Nl derived from Fig. 5b as a function of the spatial lag, l. The gray-shaded region is the spatial-resolution limit which corresponds to 55″. The power-law fitting result is indicated by the black dashed line. The orange, red, and blue dashed lines represent the observed relation in Musca (Hacar et al. 2016) and Rossete (Heyer et al. 2006), the classic Larson relation (γ = 0.76; Larson 1981), and the revised relation, σ ∝ R^0.5 (γ = l; Heyer et al. 2009), respectively.