A combustor liner (130; 430) for a gas turbine engine, the combustor liner (130; 140) comprising: a heat shield including: a shield hot side (174; 474); and a shield cold side (172; 472); a shell (142; 442) attached to the heat shield, the shell (142; 442) including: a shell hot side (166; 466) facing the shield cold side (172; 472); a shell cold side (164; 464) facing away from the shield cold side (172; 472); and a row of cooling holes (168; 468) in the shell (142; 442); a series of trip strips (184; 484) projecting from the shield cold side (172; 472), the trip strips (184; 484) running parallel to each other and all projecting from the shield cold side (164; 464) the same distance; and a series of projecting walls (186a, 186b, 186c, 186d; 486a, 486b, 486c, 486d), each projecting wall (186a, 186b, 186c, 186d; 486a, 486b, 486c, 486d) running parallel to, and opposite of, a corresponding trip strip (184; 484) and projecting from the shell hot side (166; 466) such that a distance to which each projecting wall (186a, 186b, 186c, 186d; 486a, 486b, 486c, 486d) projects from the shell hot side (166; 466) is greater for projecting walls (186a, 186b, 186c, 186d; 486a, 486b, 486c, 486d) farther from the row of cooling holes (168; 468) to create successive gaps between projecting walls (186a, 186b, 186c, 186d; 486a, 486b, 486c, 486d) and corresponding trip strips (184; 484) that decrease from the row of cooling holes (168; 468) to create a convergent channel (182; 482). a heat shield including: a shield hot side (174; 474); and a shield cold side (172; 472); a shield hot side (174; 474); and a shield cold side (172; 472); a shell (142; 442) attached to the heat shield, the shell (142; 442) including: a shell hot side (166; 466) facing the shield cold side (172; 472); a shell cold side (164; 464) facing away from the shield cold side (172; 472); and a row of cooling holes (168; 468) in the shell (142; 442); a series of trip strips (184; 484) projecting from the shield cold side (172; 472), the trip strips (184; 484) running parallel to each other and all projecting from the shield cold side (164; 464) the same distance; and a shell hot side (166; 466) facing the shield cold side (172; 472); a shell cold side (164; 464) facing away from the shield cold side (172; 472); and a row of cooling holes (168; 468) in the shell (142; 442); a series of trip strips (184; 484) projecting from the shield cold side (172; 472), the trip strips (184; 484) running parallel to each other and all projecting from the shield cold side (164; 464) the same distance; and a series of projecting walls (186a, 186b, 186c, 186d; 486a, 486b, 486c, 486d), each projecting wall (186a, 186b, 186c, 186d; 486a, 486b, 486c, 486d) running parallel to, and opposite of, a corresponding trip strip (184; 484) and projecting from the shell hot side (166; 466) such that a distance to which each projecting wall (186a, 186b, 186c, 186d; 486a, 486b, 486c, 486d) projects from the shell hot side (166; 466) is greater for projecting walls (186a, 186b, 186c, 186d; 486a, 486b, 486c, 486d) farther from the row of cooling holes (168; 468) to create successive gaps between projecting walls (186a, 186b, 186c, 186d; 486a, 486b, 486c, 486d) and corresponding trip strips (184; 484) that decrease from the row of cooling holes (168; 468) to create a convergent channel (182; 482).