Search

The extended GAO-YONG turbulence model is used to simulate the flow and heat transfer of flat-plate turbulent boundary layer, and the results indicate that GAO-YONG turbulence model may well describe boundary layer flow and heat transfer from near-wall region to far outer area, without using any empirical coefficients and near-wall treatments, such as wall-function or modified low Reynolds number model, which are used widely in all RANS turbulence models.

Using a multiscale model based on the variable interval time average method and a set of averaged equations for incompressible turbulent flows, we simulate the three-dimensional separated and reattaching flow over a swept backward-facing step. The results show that the reattachment length and vortex structure vary with the swept angles from 15° to 60° through a detailed study about velocity profile and pressure distribution. Generally the reattachment length and span wise vorticity decrease dramatically after =30°. The result fully accord with experimental data. Results show that this model is suitable for separated flows, and accurately predict the flow field, so this model should be useful in engineering application.

The upward gas-liquid cross flow around a square cylinder was simulated using two fluid model with the multi-scale turbulent model based on the variable interval time average method. The computational results show that the multi-scale turbulent model can successfully simulate lift coefficient, drag coefficient and vortex shedding characteristics of flow around a body, and can also accurately predict the void fraction distribution and flow structure. Compared with the experimental data, the results of the multi-scale model are better than that of Standard k-ε model and RNG k-ε model. Hence, the study of this paper certificates further that this model can be used in the simulation of the gas-liquid flow around bluff bodies and outher engineering application.

The unsteady flow around a triangle cylinder was simulated using the multiscale turbulence model based on the variable interval time average method. The numerical method used in this simulation is an unstructured staggered mesh scheme. The computational results show that the multiscale turbulence model can successfully simulate vortex shedding characteristics. The Strouhal number and time-averaged velocity profiles also agree better with experiments than that of the standard k-ε model.