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Prediction of pitch-damping aerodynamic derivatives using Navier-Stokes computational techniques.

机译：使用Navier-Stokes计算技术预测阻尼阻尼的空气动力学导数。

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摘要

A computationally based, multi-disciplinary approach for predicting the pitch-damping aerodynamic derivatives for symmetric flight bodies has been developed and validated for flight velocities from high subsonic/low transonic through high supersonic velocities. Although the pitch-damping aerodynamic derivatives are normally associated with unsteady or time-dependent motions, the approach presented here utilizes steady motions that result in steady flow fields to produce the aerodynamic forces and moments of interest. These motions include coning motion, looping motion and two forms of helical motion. The four motions allow the pitch-damping coefficient sum and its individual components to be determined.;The technique has been extensively validated with experimental data and comparisons with simpler theories show significant improvements in the prediction accuracy. The versatility of the technique has been demonstrated by application to a wide variety of flight body geometries over a range of flight velocities including high subsonic, transonic and supersonic velocities.;To predict the aerodynamic forces and moments of interest, a sophisticated computational capability based on the thin-layer Navier-Stokes equations has been developed. The technique allows the three-dimensional turbulent viscous flow field acting on the body in response to the applied motions to be determined. The aero-dynamic forces and moments can then be computed from the integrated effects of the pressure and viscous stresses acting on the body. A key feature of the technique is the use of a body-fixed rotating coordinate frame that allows the flow field to be viewed from a steady frame. Because this is a non-inertial coordinate frame, the governing equations have been modified to include the centrifugal and Coriolis body forces due to the coordinate system rotation. Two computational techniques have been implemented to cover the envelope of flight velocities. For high subsonic, transonic or low supersonic flows, a time-marching thin-layer Navier-Stokes technique is utilized to obtain the solution in a time-iterative manner. At supersonic velocities, a space-marching parabolized Navier-Stokes technique is applied to determine the flow field from a single pass through the computational grid.
机译：已经开发了一种基于计算的，多学科的方法来预测对称飞行器的俯仰阻尼空气动力学导数，并验证了从高亚音速/低跨音速到高超音速的飞行速度。尽管阻尼阻尼空气动力学导数通常与不定常或随时间变化的运动有关，但此处介绍的方法利用了导致运动稳定的流场来产生感兴趣的空气动力和力矩的稳定运动。这些运动包括圆锥运动，循环运动和两种形式的螺旋运动。这四个运动可以确定俯仰阻尼系数的总和及其各个分量。该技术已通过实验数据进行了广泛验证，与较简单理论的比较表明，该方法的预测精度有了显着提高。该技术的多功能性已通过在各种飞行速度（包括高亚音速，跨音速和超音速）上应用于多种飞行器几何结构得到了证明；要预测空气动力和感兴趣的力矩，基于已经开发出了薄层的Navier-Stokes方程。该技术允许确定响应于所施加的运动而作用在身体上的三维湍流粘性流场。然后可以从作用在人体上的压力和粘性应力的综合效应中计算出空气动力和力矩。该技术的关键特征是使用了固定在身体上的旋转坐标框架，该框架允许从稳定的框架查看流场。由于这是一个非惯性坐标系，因此对控制方程进行了修改，以包括由于坐标系旋转而产生的离心力和科里奥利力。已经实现了两种计算技术来覆盖飞行速度的范围。对于高亚音速，跨音速或低超音速流，可以使用时间行进的薄层Navier-Stokes技术以时间迭代的方式获得解。在超音速下，应用空间行进抛物线式Navier-Stokes技术从单次通过计算网格确定流场。

著录项

  • 作者

    Weinacht, Paul.;

  • 作者单位

    University of Delaware.;

  • 授予单位 University of Delaware.;
  • 学科 Aerospace engineering.
  • 学位 Ph.D.
  • 年度 1996
  • 页码 234 p.
  • 总页数 234
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

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