Two　geometrical　parameters,　amplitude　and　wavelength,　of　the　structure　of　the　wavy-flow　field　in　a　proton　exchange　membrane　fuel　cell　(PEMFC)　were　investigated　on　their　impacts　on　cell　performances　via　a　three-dimensional,　multiphase,　and　non-isothermal　model.　Amplitude　and　wavelength　significantly　influence　oxygen　transport,　friction　resistance,　and　current　densities　in　PEMFC　operations.　The　enhancement　of　current　density　peaks　at　an　amplitude　of　0.4　mm　and　a　wavelength　of　2　mm,　increased　by　10.40%　compared　to　the　non-wavy　design.　The　wavy　channels　would　increase　the　oxygen　concentration　gradient　and　the　viscous　friction,　increasing　entropy　generation.　The　entropy　generation　rates　increase　more　significantly　at　small　wavelengths　and　large　amplitudes.　The　entropy　generation　ratio　(EGR)　evaluates　the　performances　of　different　wavy　channels　based　on　the　accurate　description　of　oxygen　transport　in　PEMFC　without　calculating　the　associated　pumping　power　consumption　rates.　The　EGR　decreases　with　decreasing　wavelength　or　increasing　amplitude.　©　2022　Hydrogen　Energy　Publications　LLC