A nonlinearmathematicalmodelfororbitalmotionoftherotorundertheinfluenceofleakageflowthrougha labyrinth ealwasestablishedinthepresentstudy.Aninterlockingsealwaschosenforstudy.Therotor–sealsystemwas modeled asaJeffcotrotorsubjecttoaerodynamicforcinginducedbytheleakageflow.Particularattentionwasplaced on theserpentineflowpathbyspatiallyseparatingtheaerodynamicforceontherotorsurfaceintotwoparts,e.g.,the seal clearanceandthecavityvolume.Spatio-temporalvariationoftheaerodynamicforceontherotorsurfaceinthe coverage ofthesealclearanceandthecavityvolumewasdelineatedbyusingtheMuzynskamodelandperturbation analysis, respectively.Thegoverningequationofrotordynamics,whichwasincorporatedwiththeaerodynamicforce integrated zverallsealclearancesandcavityvolumes,wassolvedbyusingthefourth-orderRunge–Kuttamethodto obtain theorbitofthewhirlingrotor.StabilityoftherotatingrotorwasinspectedusingtheLiapunovfirstmethod. The resultsconvincinglydemonstratethatthedestabilizationspeedoftherotorwasreducedduetotheaerodynamic force inducedbytheleakageflowthroughtheinterlockingseal.Thenonlinearanalysismethodproposedinthepresent study isreadilyappliedtodynamicsofvariousrotor–sealsystemswithlabyrinthseals.