Background　and　objectives:　The　bicuspid　aortic　valve　(BAV)　is　a　major　risk　factor　for　the　progression　of　aortic　dilation　(AD)　because　of　the　induced　abnormal　blood　flow　environment　in　aorta.　The　differences　in　the　development　of　AD　induced　by　BAV　phenotypes　remains　unclear.　Therefore,　the　objective　of　this　study　was　to　assess　the　potential　locations　of　AD　induced　by　different　phenotypes　of　BAV.　The　different　effects　of　opening　orifice　area　and　leaflet　orientation　on　ascending　aortic　hemodynamics　in　Type-1　BAV　was　investigated　by　means　of　numerical　simulation.Methods:　Finite　element　dynamic　analysis　was　performed　on　tricuspid　aortic　valve　(TAV)　and　BAV　models　to　simulate　the　motion　of　the　leaflets　and　obtain　the　geometrical　characteristics　of　AV　at　peak　systole　as　a　reference,　which　were　used　for　aortic　models.　Then,　four　sets　of　aortic　fluid　models　were　designed　according　to　the　leaflet　fusion　types　[TAV;　BAV　(left-right-coronary　cusp　fusion,　LR;　right-non-coronary　cusp　fusion,　RN;　left-non-coronary　cusp　fusion,　LN)],　and　the　computational　fluid　dynamics　method　was　applied　to　compare　the　hemodynamic　differences　within　the　aorta　at　peak　systole.　Results:　The　maximum　opening　area　of　BAV　was　significantly　reduced,　resulting　in　alterations　in　aortic　hemodynamics　compared　with　TAV.　The　velocity　streamlines　were　essentially　parallel　to　the　aortic　wall　in　TAV.　The　average　pressure　and　wall　shear　stress　in　aorta　tend　to　be　stable.　In　contrary,　the　eccentricity　of　BAV　orifice　jet　resulted　in　high-velocity　flow　directed　toward　the　ascending　aorta　(AA)　wall　and　aortic　arch　for　LR　and　LN;　RN　features　an　asymmetrical　velocity　distribution　toward　the　outer　bend　of　the　middle　AA,　and　eccentric　flow　tends　to　impact　the　distal　AA.　As　the　flow　angle　is　associated　with　distinct　flow　impingement　locations,　different　degrees　of　WSS　and　pressure　concentration　occur　along　the　aortic　wall　from　the　AA　to　the　aortic　arch　in　three　BAV　types.Conclusions:　The　BAV　morphotype　affects　the　aortic　hemodynamics,　and　the　abnormal　blood　flow　associated　with　BAV　may　play　a　role　in　AD.　The　different　BAV　phenotypes　determine　the　direction　of　blood　flow　jet　and　change　the　expression　of　dilation.　LR　is　likely　to　cause　dilation　of　the　tubular　AA;　RN　results　in　dilation　of　the　middle　AA　to　proximal　aortic　arch;　and　LN　causes　an　increased　incidence　of　the　tubular　AA　and　the　proximal　aortic　arch.(c)　2022　Elsevier　B.V.　All　rights　reserved.