An efficient adjoint method for the aero-stealth shape optimization design

Li, Ming; Chen, Jiaojiao; Feng, Xiang; Qu, Feng; Bai, Junqiang

doi:10.1016/j.ast.2021.107017

Cited by 15 publications

(10 citation statements)

References 41 publications

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“…Based on these modules, an aerodynamic shape optimization system with a highfidelity solver and a gradient-based optimizer is built. This system has been widely applied by the author's group and other teams in the field of civil aircraft aerodynamic design [17,[41][42][43][44][45]. The specific workflow of the design system is shown in Figure 1.…”

Section: Methodsmentioning

confidence: 99%

“…This paper adopts the B-spline-based Free-Form Deformation (FFD) method to parameterize the whole TBW geometry. The FFD approach has been applied widely in aerodynamic optimization designs [42][43][44][45][47][48][49]. For this method, it mainly has two advantages: firstly, it need not interpolate or fit the baseline configuration, and it only needs fewer design variables to manage the aerodynamic shape deformation.…”

Section: Geometric Parameterizationmentioning

confidence: 99%

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Effects of Static Stability Margin on Aerodynamic Design Optimization of Truss-Braced Wing Aircraft

Qiao

et al. 2023

Aerospace

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Currently, the aviation industry is facing an oil and energy crisis and is contributing much more greenhouse gas emissions to the environment. Aircraft design approaches, such as aerodynamic shape optimization, new configuration concepts, and active control technology, have been the primary and effective means of achieving goals concerning fuel burn, noise, and emissions. For now, the design problems of relaxed static stability (RSS, an active control technique) and truss-braced wing (TBW) configurations with high-fidelity aerodynamic shape optimization methods have been investigated widely to promote aerodynamic performance. Nevertheless, they are studied almost always separately, and the combination of exploration and refined design is rarely presented. Therefore, the purposes of this work are to evaluate the benefits of RSS on a full TBW wing–body–tail configuration under various flight conditions and the effects on multi-components and to further explore the potential and analyze the aerodynamic features with the combination of shape optimization and RSS. To address these issues, on the one hand, a range of seven static stability margins are adopted to evaluate its effects with a high-fidelity Reynolds-averaged Navier–Stokes solver. On the other hand, seven cases of drag minimization multipoint aerodynamic design optimization are performed, which are with 600 shape variables and 13 twist variables, subject to lift coefficient, trim, and thickness constraints. The results indicate that with RSS only, the initial configuration has a 2.39% drag reduction under cruise conditions and a 3.01% and a 5.24% drag reduction under two off-design conditions. Additionally, the effects on the multi-components are observed and analyzed. Moreover, all of the optimized configurations with RSS have 2.13%, 2.42%, and 2.12% drag reductions under cruise conditions, drag divergence conditions, and near-buffet-onset conditions, respectively. The most promising optimized configuration has a lift-to-drag ratio of 24.48 with an aerodynamic efficiency of 17.14. The evaluations with a series of off-design points also present high-level aerodynamic efficiency.

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Section: Methodsmentioning

confidence: 99%

Section: Geometric Parameterizationmentioning

confidence: 99%

Effects of Static Stability Margin on Aerodynamic Design Optimization of Truss-Braced Wing Aircraft

Qiao

et al. 2023

Aerospace

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“…Before analyzing the scattering of rudder seam, a surface scattering contribution decomposition method for aircraft scattering is introduced. 33 Generally, the radar cross section can be given by the following formula 34 :with the distance between the target and the observation point R , the electric field intensity of the scattered wave at the observation point E s , and the electric field intensity of the incident wave at the target E i . The radar cross section is a scalar, which cannot fully reflect the phase information.…”

Section: Analysis Of Scattering Characteristics Of Rudder Seammentioning

confidence: 99%

Investigations on electromagnetic scattering characteristics of aircraft rudder considering electromagnetic discontinuities

Gu,

Chen,

Gao

et al. 2023

Proceedings of the Institution of Mechanical Engineers, Part G:

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This work investigates the scattering characteristics of the rudder structure of aircraft considering electromagnetic discontinuities through multi level fast multipole algorithm (MLFMA) of the computational electromagnetics. Firstly, the scattering characteristics of the rudder seam and its influence on the omnidirectional radar cross section (RCS) are performed. Based on the traditional high-frequency analysis theory, the source and spatial contribution distribution of seam scattering are further studied. Numerical results demonstrate that the sidewall of the rudder seam is an important scattering source, and the radar absorbing material (RAM) coated on the sidewall of the seam has a good RCS reduction effect. In addition, this work presents the influence of the rudder deflection on the stealth performance, analyzes the effect of the rudder movement of the ordinary aileron and the split drag rudder on the scattering characteristics of the whole aircraft. The common aileron has little effect on the stealth performance of the aircraft, and it only causes scattering peak in the direction opposite to the control surface. However, the split drag rudder has great damage to the opposite direction stealth performance of the aircraft. When its deflection angle is 45°, the mean value of the opposite direction RCS increases by about two orders of magnitude compared with the deflection angle 0° state. The results indicate that the structure of aircraft rudder has a significant impact on the RCS characteristics of the whole aircraft.

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“…In particular, the adjoint variable method (AVM) using volume-type shape derivative, which is expressed with volume integrals over a bounded domain, has been often investigated both in frequency domain [5][6][7][8] and in time domain [9,10] mainly for 2D problems. It should be noted that the automatic differentiation (AD) is sometimes used in the context of the gradient-based SO; see [11] for the AD regarding the volume-type shape derivative in 3D frequency domain.…”

Section: Introductionmentioning

confidence: 99%

An electromagnetic shape optimisation for perfectly electric conductors by the time-domain boundary integral equations

Takahashi

2024

Engineering with Computers

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This study proposes a shape optimisation framework for unsteady electromagnetic scattering problems on the basis of the time-domain boundary integral equation method, focusing on the perfectly electric conductors (PECs). The boundary-only formulation is ideal for treating a shape optimisation problem in exterior domains. However, the electromagnetic shape optimisation in concern has been unrealised with the boundary integral approach regardless of the fact that the boundarytype shape derivative has been known in the literature. The first contribution of the present study is to derive a novel expression of the shape derivative in terms of the surface current densities of the primary and adjoint problems, by considering that the surface current density is handled by usual integral equations methods. The second contribution is to clarify the integral representations and equations of the adjoint electromagnetic fields in terms of the reversal time. These theoretical achievements possess a high affinity with the standard spatial discretising approach (i.e. RWG basis) whenever the temporal basis is sufficiently smooth. The numerical experiments confirmed the reliability of the proposed shape optimisation methodology and indicated the capability to deal with scientific and engineering applications.

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An efficient adjoint method for the aero-stealth shape optimization design

Cited by 15 publications

References 41 publications

Effects of Static Stability Margin on Aerodynamic Design Optimization of Truss-Braced Wing Aircraft

Effects of Static Stability Margin on Aerodynamic Design Optimization of Truss-Braced Wing Aircraft

Investigations on electromagnetic scattering characteristics of aircraft rudder considering electromagnetic discontinuities

An electromagnetic shape optimisation for perfectly electric conductors by the time-domain boundary integral equations

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