一种半隐式的气动弹性时域求解方法
SEMI-IMPLICIT SOLUTION OF AEROELASTIC EQUATIONS IN TIME DOMAIN
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摘要: 针对结构小幅运动、流动强非线性的气动弹性问题,基于Adams 隐式方法发展了一种半隐式的线性多步法(SILMS)。将隐式的广义气动力项采用显式插值求解,结构项仍采用隐式格式计算,该方法融合了显式方法耦合简单和隐式方法稳定性好的特点。结构运动采用模态坐标描述,流动方程应用计算流体力学(CFD)技术求解,二者采用松耦合方法进行时域推进。算例计算了一个标准气动弹性模型(Isogai wing)的颤振结果,并与几种经典的时域模拟方法进行了比较,证明该方法具有效率高、稳定性好、精度高的优点。Abstract: A semi-implicit linear multi-step scheme (SILMS) based on Adams implicit method is developed for aeroelastic analysis in time domain. The structural part is solved implicitly while the general aerodynamic part is solved explicitly, instead of calling the solvers of flow field. Its accuracy and stability are better than Adams predictor-corrector procedure. And the characteristics of Adams explicit method such as high efficiency and convenience remain well. Thus the existent solvers of flow and structure can be modularized to solve the aeroelastic problem. The transonic areoelastic response of an aeroelastic model (Isogai wing) is calculated. The structural motion is represented by the generalized coordinates and the unsteady loads are computed through computational fluid dynamics (CFD). The present method is compared with several classic time-domain simulation methods, and the results clearly validate its precision, stability and efficiency.