Título: Approximate analytical methodology for calculating friction factors in flow through polygonal cross section ductsAutor: Leandro Alcoforado SphaierLeonardo Santos de Brito AlvesAno: 2018DOI: 10.1007/s40430-018-1019-6Revista: Journal of the Brazilian Society of Mechanical Sciences and EngineeringISSN: 16785878Idioma: Inglês