超临界翼型跨声速抖振CFD计算和POD分析

CFD computation and POD analysis for transonic buffet on a supercritical airfoil

使用二阶迎风Roe格式、隐式时间推进和S-A(Spalart-Allmaras)一方程湍流模型,通过求解基于格心格式有限体积法的RANS方程模拟了OAT15A超临界翼型的跨声速抖振流场。在模拟出激波/附面层相互干扰诱发的抖振现象的基础上,对翼面激波运动过程中的气流分离泡变化规律开展研究,揭示出激波变化相位略微超前于升力系数相位的非定常现象。为剖析跨声速抖振的物理成因,将抖振计算的非定常解作为快照,应用本征正交分解POD(Proper Orthogonal Composition)方法提取POD模态,从流场相干结构的角度对跨声速抖振现象进行了分析。

The transonic buffet flow on the OAT15A supercritical airfoil is simulated by the solution of the cell-centered finite-volume method （FVM） based RANS （Reynolds-averaged Navier-Stokes） equations with the S-A （Spalart-Allmaras） one-equation turbulence model, as well as the implicit time-stepping scheme and the Roe scheme. On the basis of successful simula- tion of transonic buffet phenomenon caused by the shock-boundary layer interaction, studying the evolution of flow separation and it reveals a hysteresis phenomenon that the phase of shock move- ment is slightly ahead of the phase of lift fluctuation. To view the physical nature of transonic buffet, apply POD （Proper Orthogonal Composition） method to extract POD modes with the transient results as snapshots. An POD analysis from the perspective of coherent structure has been implemented.