Evolution from differential rotation to average uniform rotation for three different viscosity values, ν₁/(/d) = 0.028 (square), ν₂/(/d) = 0.005 (hexagon), and ν₃/(/d) = 0.0005 (triangle). Left: Azimuthally averaged angular velocity (⟨ω″⟩ at times (in days) as listed to the right of each curve and in a column corresponding to the ν value. The initial ⟨ω″⟩ profile is indicated with asterisks joined by the continuous line. The time in days for each curve is listed under its corresponding viscosity. The small “x” (top curve) corresponds to Case 1, in which the calculation was started in uniform rotation. Right: Plot showing that all models tend toward average uniform rotation on the viscous timescale, τ_vis = r²/ν. The ordinate is the ⟨ω″⟩ value of the surface layer, r = 6.6 R_⊙. The abscissa is t/τ_vis where t is the time listed next to each curve in the left hand panel of this figure. Symbols are the same as in the left panel.