a: density distribution of the Ulrich (1976) model of the envelope. The black lines are the streamlines, b: same as the first panel but for the constant-J case (Sect. 4.2.1). c: streamline for θ₀ = 0 in the constant-J case. Note that ρ depends only on r in the colored region, d: streamlines altered by disk-like inner envelope. The green area represents the disk-like envelope supported by thermal pressure and confined by shocks at the surface (Sect. 4.2.2). The orange area shows the schematic diagram of a Keplerian disk within the centrifugal barrier at R_C, with a flare index of 1.3 (e.g., Chiang & Goldreich 1997). The vertical orange-red bar shows the head-on strong shocks at the centrifugal barrier (redder color means stronger shocks). The horizontal blue bar roughly represents the shocked surface of the envelope due to oblique flows, e: streamlines in the envelope viewed from the pole. The gray and yellow regions represent the outer and inner envelopes, respectively. The solid blue line depicts the free-fall parabolic trajectory in the midplane. The dotted and dashed lines are the pressure-modified trajectories in the midplane and on the surface of the inner envelope, respectively, f: schematic map in edge-on view. The gray, green, and orange regions are the outer envelope, disk-like envelope, and the disk, respectively. The black strips are the near-middle-plane (lower left) and off-midplane (upper right) streamers. The arrows indicate the outflows. The red dots highlight the shocked surfaces of the disk-like envelopes.