Mass-size relation of ellipsoidal clusters; the total mass inside the ellipsoidal region defined with gas kinematics overplotted with a model of the corresponding levels of turbulence with γ = 1 (upper panel) and 0.7 (lower panel). The velocity dispersion increases from the bottom to the top curve. Simulation results at time before 2 Myr are plotted with thin lines. The model is in good agreement with simulation only after the protocluster gains enough mass, possibly implying that the time dependent terms and ram pressure should not be neglected at early stage.