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Transonic aeroelasticity solutions using finite elements in an arbitrary Lagrangian-Eulerian formulation.

机译：使用任意Lagrangian-Eulerian公式中的有限元进行跨音速气动弹性求解。

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摘要

In this dissertation, a finite element technique for the solution of transonic aeroelasticity problems is presented and demonstrated using several two-dimensional configurations. The flow field behavior is represented by the unsteady Euler equations, written in an arbitrary Lagrangian-Eulerian form, while the structural motion is described using Lagrange's equations. Both the fluid and structural equations are discretized in the spatial domain using finite element methods. The solution technique uses a novel approach in which the fluid equations are solved simultaneously with the structural equations using the same Runge-Kutta time marching scheme for both.; Transonic solutions are presented for prescribed oscillatory motion of an isolated airfoil in both pitch and plunge degrees of freedom. Airfoil surface pressures computed using this technique show good agreement with published analytical results and test data. Flutter solutions are also presented for the airfoil and are compared to the results of other analytical techniques. Supercritical as well as subcritical bifurcation to a stable limit cycle was observed in the solutions. Under certain conditions the limit cycle oscillations were observed to modulate between two different amplitudes.; A detailed panel flutter study is also presented for the Mach number range from 0.8 to 2.5. The two-dimensional panel used in the study is represented by nonlinear finite elements that account for in-plane stretching induced by transverse deflections. The existence of traveling wave motion with shocks moving across the panel surface is shown. When the dynamic pressure was raised above the stability limit, divergence was observed at Mach numbers below unity, flutter and divergence were observed at Mach one, and only flutter was found in supersonic flows. Flutter was also found in very thin panels at high transonic Mach numbers. Near Mach one, flutter consists of traveling wave motion with shocks on the surface of the panel. In the Mach number range from about 1.3 to 1.5, the higher modes of the panel respond, resulting in high stresses. The aeroelastic response of these modes is shown to be effectively eliminated by the addition of damping.
机译：本文提出了一种跨声速气动弹性问题的有限元求解方法，并利用几种二维结构进行了验证。流场行为由以任意Lagrangian-Eulerian形式编写的非定常Euler方程表示，而结构运动是使用Lagrange方程描述的。使用有限元方法在空间域中将流体方程和结构方程离散化。求解技术使用一种新颖的方法，其中使用相同的Runge-Kutta时间行进方案同时求解流体方程和结构方程。提出了跨音速解决方案，用于规定俯仰和俯冲自由度下的孤立翼型的规定振荡运动。使用该技术计算的机翼表面压力与已发表的分析结果和测试数据显示出很好的一致性。还提出了针对翼型的颤振解决方案，并将其与其他分析技术的结果进行了比较。在溶液中观察到超临界和亚临界分叉达到稳定的极限循环。在某些条件下，观察到极限循环振荡在两个不同的振幅之间调节。还提出了详细的面板颤振研究，其马赫数范围为0.8到2.5。研究中使用的二维面板由非线性有限元表示，这些非线性有限元解释了由横向变形引起的面内拉伸。示出了行波运动的存在以及在面板表面上移动的冲击。当动压升高到稳定极限以上时，在马赫数小于1时观察到发散，在马赫数1处观察到颤动和发散，在超音速流中仅发现颤动。在超音速马赫数很高的超薄面板中也发现了颤振。在马赫一号附近，颤动包括行波运动和面板表面的震动。在马赫数从大约1.3到1.5的范围内，面板的较高模式会响应，从而导致较高的应力。通过增加阻尼，可以有效地消除这些模式的气动弹性响应。

著录项

  • 作者

    Davis, Gary Alan.;

  • 作者单位

    University of California, Los Angeles.;

  • 授予单位 University of California, Los Angeles.;
  • 学科 Engineering Aerospace.
  • 学位 Ph.D.
  • 年度 1994
  • 页码 318 p.
  • 总页数 318
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 航空、航天技术的研究与探索;
  • 关键词

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