A biological fluid transport device comprises a cutwater at the junction of at least two blood flow paths. The cutwater is substantially straight, substantially vertical, or both. At least one of the fluid paths may be tubular, and in some embodiments all of the fluid paths are tubular. The shear sensitive fluid may be, without limitation, blood, blood-based combinations, cell culture media, cell suspensions, proteins, and microcapsule suspensions. The device may be part of an extracorporeal circuit (e.g., blood during heart-lung bypass procedures or blood processing), but it need not be. Preferred embodiments of the device include, without limitation, kinetic pumps, mass transfer devices, filters, reservoirs, and heat exchangers.