Determination of epsilon for Omega vortex identification method

In the present paper, epsilon (epsilon) in the Omega vortex identification criterion (Omega method) is defined as an explicit function in order to apply the Omega method to different cases and even different time steps for the unsteady cases. In our method, epsilon is defined as a function relating with the flow without any subjective adjustment on its coefficient. The newly proposed criteria for the determination of epsilon is tested in several typical flow cases and is proved to be effective in the current work. The test cases given in the present paper include boundary layer transition, shock wave and boundary layer interaction, and channel flow with different Reynolds numbers.