超声速来流横向狭缝喷流标量输运的混合RANS/LES模拟

采用基于时均湍流模型的混合RANS/LES模拟方法对超声速来流狭缝横向喷流标量输运过程进行大涡模拟,控制方程对流项采用五阶精度的WENO格式求解,过滤后的组分方程中的亚格子组分对流通量采用梯度扩散模化.模拟得到了超声速来流狭缝横向喷流大尺度涡和组分的演化过程,研究表明喷流具有明显的非定常周期性特点,并且组分随时间的空间分布特征决定于流动的大尺度结构.模拟得到的压力的统计时均结果和实验结果定性一致,但喷流前后的分离区较实验值过大,这表明混合RANS/LES需要进一步改进.

Hybrid RANS/LES Simulation for Scalar Transport of Slot Injection into a Supersonic Stream

Hybrid RANS/LES simulation was conducted to investigate the scalar transport of slot injection into a supersonic stream.The governing equations of large scale eddies were solved with fifth-order WENO scheme and the effect of small scale eddies was simulated by using one equation subgrid scale model.The subgrid convective species flux in the filtering species equation was modeled by using gradient diffusion assumption.The results reveal the behavior of large structures and instantaneous distribution of species.Simulations show that the coherent structures evolve in a periodic mechanism and the large eddy structures dominate the transport of species.Time averaged wall pressure distribution is qualitatively consistent with the experimental measurements.The separate regions in front of and behind the jet are both over predicted which indicts the hybrid model need further modification.