Abstract: The flow field of oscillatory wing was divided into different subdomains according to its flow characteristic using the dynamic chimra grid technique. Different flow-control equations were used in different subdonmain in order to improve computing efficiency. A smaller and denser clingy grid moving along with oscillatory wing was generated in which the Naviers-Stokes equations were used, while a bigger and sparser background grid was generated for all flow field in which the Euler equations were used. Flow information communicating between two subdomains was implemented through the dynamic chimra grid technique. A numerical example shows that, for non-steady viscous flow, the adopted method is reasonable, and is more efficient than single grid with thorough NaviersStokes equations.

Key words: dynamic chimra grid technique, Naviers-Stokes equation, unsteady flow