A fluid distributor includes a distributor body defining a plurality of fluid distributor passages therethrough. Each of the fluid distributor passages winds in swirl direction about a swirl axis. The swirl direction defines a swirl angle of at least 60 degrees relative to the swirl axis. Each of the fluid distributor passages defines a floor and opposed ceiling, and an opposed pair of sidewalls. At least one of the floor and/or the ceiling is vaulted to define a surface that is angled less than 60 degrees relative to the swirl axis.