In this paper, a new concept of an electronic device cooling method is proposed. In this method, extremely thin fins are used for swinging back and forth in a flowing fluid. The boundary layers attaching on the fins are then contracted and disturbed, and the heat transfer rate of the fins can be enhanced remarkably. The dynamic behavior between the fins and fluid is classified into a class of the moving boundary problems. A Galerkin finite element formulation with an arbitrary Lagrangian-Eulerian kinematic description method is adopted to solve this problem. The parameters of velocities of the fluid and the swinging speed of the fins are employed to investigate the variations of the flow and thermal fields. The results show that the velocity and thermal boundary layers may be contracted and disturbed, which results in a significant heat transfer enhancement, being attained.