In order to research the influence of curvature on flow stability in circular pipe

two circular pipe models of axial flow of spanwise curvature and circumferential flow of axial curvature were studied. For two models

the stabilities and disturbance evolutions of difference curvatures were calculated by the linear stability theory. And the results were compared with channel flow. Then the influences of curvature on basic flow

eigenvalue and eigenfunction were obtained. Result showed that

along with the greater curvature

the basic flow would deflect inside

the axial wavenumber of disturbance wave became greater

the growth rate changed smaller

the unstable region of neutral curve diminished and symmetry of eigenfunction got worse. So curvature has a stabilizing influence on disturbances in boundary layers and the stability will be better when the curvature increases gradually in certain rang.