微射流作动器外流场紊流数值分析

Turbulent Numerical Study on the External Flowfield of Micro-jet Actuator

采用隐式高阶紧致差分格式、Beam-Warming近似因式分解法结合低雷诺数k-ε模型求解Faver平均N-S方程,对二维、粘性、非定常、可压微作动器外流场进行数值模拟。内置似牛顿子迭代用来消除因近似因式分解、线性化、显式使用边界条件及隐式一边采用低阶空间离散近似所带来的误差,以提高精度。隐式高阶紧致差分格式具有高的精度和强的稳定性。与其它人工粘性方法相比,隐式高阶数值过滤方法对许多情况,特别是对于低马赫数的流场计算有明显优越性。计算结果和实验现象相当吻合。

The Faver-average N-S equations are solved by using Beam-warning approximate factorization method combined with k-ε model and a high-order compact-difference scheme for the micro-jet actuator external flowfield,, at the same time, numerical simulation is performed to the compressible, two dimensional, time-dependent and viscous flowfield. Newton-like subiterations within each physical time step are employed to achieve temporal accuracy, remove factorization errors and reduce errors caused by linearization and the low spatial order of accuracy of the implicit operator. The implicit high-order compact-difference has high accuracy and good robustness. The algorithm demonstrates high accuracy compared to both second-order and upwind-biased methods. For several cases, particularly very low-Mach number flows, filtering is a superior alternative to damping. The calculating results tally with the experimental results.