Applied Mathematics Seminar

Date/Time/Room: Thursday (1/17/2002) at 2:00 pm in 487 Pickard Hall

Speaker: Zhaoshun Zhang, Tsinghua University, Beijing, China

``Numerical study of transition in a cylindrical pipe flow''

Abstract: The paper presents numerical study on flow transition in both smooth and rough cylindrical pipe by small suction and blowing at pipe wall at Reynolds number 3000 based on the maximum velocity of the laminar flow and radius of the pipe. The development of the PSB disturbance is simulated by means of pseudo spectrum element method. The transitional process in smooth is described in the paper that the disturbances are growing rapidly in a short part of the pipe after they develop gradually in sufficient long distance. When the rapid growth of disturbances occurs the time step of integration should be decreased and then the flow transits to turbulent. The transition in the rough pipe flow occurs in asymmetrical wall or random roughness and a equivalent relationship between the roughness and disturbance amplitude is proposed.