Transonic-Aerodynamic-Influence-Coefficient Approach for Aeroelastic and MDO Applications

Abstract

A developed transonic-aerodynamic-in uence-coef cient (TAIC) method is proposed as an ef cient tool for applications to utter, aeroservoelasticity, and multidisciplinary design/analysis optimization. Several plausible procedures for AIC generation are described. The modal-based AIC procedure is formally established as a general AIC scheme applicable to all classes of computational uid dynamics (CFD) methods. The present TAIC method integrates the previous transonic equivalent strip (TES) method with the modal AIC approach; its computer code ZTAIC has a similar input format to that of doublet lattice method (DLM) except with the additional steady pressure input. The versatility of ZTAIC is shown by two sets of cases studied: those cases with pressure input from measured data and those from CFD computation. Computed results of unsteady pressures and utter points are presented for six wing planforms. In contrast to the usual CFD practice, the effective use of the modal AIC in ZTAIC is clearly demonstrated by the utter calculations of the weakened and solid 445.6 wings, where the CPU time of a transonic utter point using warm-started AIC is less than 1 min on a SUN SPARC20 workstation. Moreover, the AIC capability allows ZTAIC to be readily integrated with structural nite element method (FEM). Hence, it is most suitable to be adopted in a multidisciplinary design (MDO) environment such as ASTROS.

Sensitivity Study of Downwash Weighting Methods for Transonic Aeroelastic Stability Analysis

“…The results presented by Chen et al [27], as shown in Fig. 9, indicate that the transonic dip phenomenon is well characterized in the solution with the ZTAIC method [29], and the computed flutter speed also presents good agreement with the experimental data.…”

“…Table 2 presents a comparison between the transonic flutter computation based on the correction using steady and unsteady nonlinear pressures and experimental results [6]. Table 3 includes comparisons with some well-known aeroelastic analysis codes [27][28][29] with unsteady downwash correction procedure results.…”

“…The ZTAIC method [27] is a modal aerodynamic influence coefficient matrix correction method, based on the transonic equivalent strip method developed by Liu et al [12] and further extended by Chen et al [27]. The CAP-TSD method is a time domain finite difference solution of the transonic small disturbance equation [29] coupled with a finite element structural-dynamic model.…”

Unified Aerodynamic-Influence-Coefficient Approach for Aeroservoelastic and Multidisciplinary Optimization Applications

“…]} (7) where U d is the control surface displacement and the last exponential term is the downwash due to a sinusoidal gust eld. The AIC matrix ordinarily relates the downwash to the aerodynamic forces on lifting surfaces.…”

An overview of recent developments in computational aeroelasticity

“…Several investigators (ref. [54][55][56][57] have calculated specific cases, but the complete trend has not been demonstrated, possibly because it is a very large computational task. It has been found that the modal data must be calculated for the wings using plate elements.…”