STREAMLINE ADAPTIVE GRID METHOD FOR COMPLEX FLOW COMPUTATION

A concept of generating and adapting grids according to flow streamlines is employed in the prediction of complex fluid flows. In general, this method retains the merits of body-fitted coordinates in the near-wall regions. Moreover, this approach generates new coordinate lines according to the streamline patterns of the preceding solution based on either Cartesian or curvilinear grid systems and adapts sufficient grids in regions where high resolutions are needed so that the difficulty of numerical diffusion is significantly reduced. To give systematic coordinate transformations, conservation equations applicable in the general nonorthogonal curvilinear coordinate system are derived by the method of generalized tensors. A treatment of near-wall turbulence suitable in the general curvilinear coordinate system is also presented. The superiorities of the present approach are demonstrated by studying the laminar/turbulent flow over a backward facing step and the flow induced by a two-dimensional turbulent jet injected into cross flow. The results show remarkable successes for the case of laminar flow over a backward facing step in the whole domain and the case of a turbulent jet into cross flow in the prediction of detailed flow structures.