Abstract: A bulkhead structure for separating two compartments in an aircraft engine inlet cowl or the like and for promoting fluid flow between the compartments is described which comprises a first flanged member having a first flange attached to the periphery of the bulkhead and a second flange having in a surface thereof a plurality of corrugations extending across the width of the second flange, and a second flanged member having a first flange presenting a first surface for attachment to the walls defining the compartments separated by the bulkhead and presenting a second surface attached to the second flange of the first flanged member for defining with the corrugations a corresponding plurality of passageways past the bulkhead at the periphery thereof.