Comparison of the triple-deck theory, interactive boundary layer method, and Navier-Stokes computation for marginal separation

The steady two-dimensional separation of an incompressible boundary layer flow within a channel was solved independently by three different methods: the triple-deck method of marginal separation, the interactive boundary layer method, and the full Navier-Stokes computation. From comparison of the results between these three methods, the accuracy and appropriateness of each method was determined. The critical condition beyond which the steady marginal separation solution of triple-deck method does not exist was related to a physical phenomenon in which the separation bubble becomes unsteady. Factors such as Reynolds number and pressure gradient distribution which might influence the accuracy of the marginal separation solution were also investigated.