Abstract: A modified penalty scheme is discussed for solving the Stokes problem with the Crouzeix-Raviart type nonconforming linear triangular finite element. By the L2 projection method, the superconvergence results for the velocity and pressure are obtained with a penalty parameter larger than that of the classical penalty scheme. The numerical experiments are carried out to confirm the theoretical results.

Key words: stage-structured, impulsive stocking, continuous harvesting, global attractivity, permanence, L² projection method, Crouzeix-Raviart type nonconforming finite element, penalty scheme, superconvergence