Measured SFR surface density Σ _SFR as a function of (a) Σ/ t _{ff, 0} and (b) Σ/ t _ver for all numerical models, where t _{ff, 0} = (3π/(32 Gρ ₀)) ^1/2 and t _ver = H _diff/ v _{z, diff} are computed using time-averaged values of the variables. The points and error bars give the mean and standard deviations over t/ t _orb = 2–3. The dotted lines in (a) and (b) show our best fits for imposed unity slopes, Σ _SFR = 0.008(Σ/ t _{ff, 0}) and Σ _SFR = 0.0025(Σ/ t _ver), respectively.