Aerospace Science and Technology最新文献_第3页

Experimental and numerical investigations into cold flow characteristics of multiple micro-mixing jets for hydrogen-rich gas turbines 富氢燃气轮机多重微混合喷流冷流特性的实验和数值研究

IF 5 1区工程技术 Q1 ENGINEERING, AEROSPACE

Aerospace Science and Technology

Pub Date : 2024-10-31 DOI: 10.1016/j.ast.2024.109702

Xuanren Chen , Hui Wang , Xiangyu Wang , Ning Wang , Xiang Liu , Dehuang Huang

To explore the flow field of micro-mixing jets, cold flow characteristics of a model Micromix burner were investigated by particle image velocimetry (PIV) system and Large-eddy simulation (LES) model. Results show that LES results are in good agreement with experimental results. In the flow field of multiple micro-mixing jets, the jet velocities of nozzles farther away from the burner center have a high increase and decay rate. When the outlet Reynolds number increases, the Reynolds stress increases first and then decreases in the merging region indicating that the velocity fluctuation disappears in the second jet half, but it has little effect on the flow field structure. Comparing the flow fields of round multiple micro-mixing jets, the merging point and combined point in the elliptical jets flow field move backward. Moreover, the maximum velocity for elliptical jets is also faster than the round jets, which is caused by the high turbulent kinetic energy in the elliptical jet flow field. When the tube spacing increases from 2 to 3 times the tube diameter, positions of the two feature points change linearly. Further, the surrounding jets can decrease the velocity attenuation of the center nozzle and elongate the axial length of the two feature regions.

为了探索微混合射流的流场，我们利用粒子图像测速仪（PIV）系统和大涡流模拟（LES）模型研究了模型 Micromix 燃烧器的冷流特性。结果表明，LES 结果与实验结果非常吻合。在多个微混合射流的流场中，距离燃烧器中心较远的喷嘴的射流速度具有较高的上升率和衰减率。当出口雷诺数增大时，雷诺应力在合并区域先增大后减小，表明速度波动在后半段射流中消失，但对流场结构影响不大。比较圆形多重微混合射流的流场，椭圆形射流流场中的合并点和结合点向后移动。此外，椭圆形射流的最大速度也比圆形射流快，这是因为椭圆形射流流场中的湍流动能较高。当管道间距从管道直径的 2 倍增加到 3 倍时，两个特征点的位置呈线性变化。此外，周围的射流可降低中心喷嘴的速度衰减，并拉长两个特征区域的轴向长度。

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引用次数: 0

Prediction of pressure distribution and aerodynamic coefficients for a variable-sweep wing 预测变掠翼的压力分布和空气动力系数

IF 5 1区工程技术 Q1 ENGINEERING, AEROSPACE

Aerospace Science and Technology

Pub Date : 2024-10-31 DOI: 10.1016/j.ast.2024.109706

Yuqi Lei , Xiaomin An , Yihua Pan , Yue Zhou , Qi Chen

To satisfy the performance requirements across multiple speed ranges, a variable-sweep wing (sweep angle range from 25° to 40°) is derived from the BQM-34 “Firebee” drone model. However, predicting aerodynamic characteristics across various flight conditions and sweep angles is a challenging task. Traditional methods like CFD and wind tunnel testing are both time consuming and expensive. In order to efficiently predict the pressure distributions and aerodynamic coefficients, a novel network that combines a Radial Basis Function Network (RBFN) and a Convolutional Auto-Encoder (CAE) is proposed. Two distinct loss function methods, the standard Pressure-Targeted Method (PTM) and the newly developed Comprehensive Evaluation Method (CEM), are employed to optimize the network's predictive performance. These methods are evaluated on datasets with both trained and untrained sweep angles. The results show that while both PTM and CEM accurately predict pressure distributions, the enhanced CEM provides more uniform and reliable predictions. Moreover, the CEM method significantly outperforms PTM in predicting aerodynamic coefficients, reducing errors by over 50%. The proposed RBFN-CAE network with the CEM loss function offers an effective way to predict the aerodynamic characteristics of a variable-sweep wing, improving predictive models in aerodynamic applications.

为了满足多种速度范围内的性能要求，从 BQM-34 "火蜂 "无人机模型中衍生出一种可变后掠角机翼（后掠角范围从 25° 到 40°）。然而，预测各种飞行条件和扫掠角下的气动特性是一项具有挑战性的任务。CFD 和风洞试验等传统方法既耗时又昂贵。为了有效预测压力分布和空气动力系数，我们提出了一种结合径向基函数网络（RBFN）和卷积自动编码器（CAE）的新型网络。为了优化网络的预测性能，采用了两种不同的损失函数方法，即标准的压力目标法（PTM）和新开发的综合评估法（CEM）。这些方法在经过训练和未经训练的扫描角度数据集上进行了评估。结果表明，虽然 PTM 和 CEM 都能准确预测压力分布，但增强型 CEM 能提供更均匀、更可靠的预测。此外，CEM 方法在预测空气动力系数方面明显优于 PTM，误差减少了 50%以上。所提出的带有 CEM 损失函数的 RBFN-CAE 网络为预测变掠翼的气动特性提供了一种有效的方法，从而改进了气动应用中的预测模型。

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引用次数: 0

Experimental study on loss and flow mechanism of variable stator vanes in high-pressure compressor with bleed 带排气的高压压缩机中可变定子叶片的损耗和流动机理的实验研究

IF 5 1区工程技术 Q1 ENGINEERING, AEROSPACE

Aerospace Science and Technology

Pub Date : 2024-10-31 DOI: 10.1016/j.ast.2024.109686

Chen Xu, Shaowen Chen, Zehao Li

In modern compressors, variable stator vanes are increasingly utilized. These vanes require a specific gap between their leading and trailing edges and the casing/hub to prevent contact during rotation. For multi-stage axial compressors employing variable stator vanes, understanding the impact of clearance variations on compressor performance is crucial during design. This study focuses on experimental research conducted on a high-pressure compressor equipped with variable stator vanes and bleed, using a real engine structure. The investigation delves into the loss characteristics and flow mechanisms within the variable mechanism's flow field. Results show that, with the identical penny diameter, increasing radial clearance initially decreases flow field loss, but then loss rises, reaching a minimum with a 2 mm (1.25% blade height) clearance. Conversely, with the same radial clearance, increasing penny diameter initially increases loss, which then decreases, with larger penny diameters resulting in smaller losses. Based on these findings, it can be inferred that a clearance of around 2 mm substantially reduces losses within the vane. Losses within 0–10% of the blade height from the endwall mainly stem from penny leakage vortex and their interaction with passage vortex, while losses within 10–20% of the blade height primarily arise from passage vortex, thus mitigating overall losses. The study demonstrates that, compared to zero-clearance vanes, variable stator vanes with a partial gap resulted in lower total pressure losses and better flow field control.

在现代压缩机中，越来越多地使用可变定子叶片。这些叶片的前缘和后缘与机壳/轮毂之间需要一定的间隙，以防止在旋转过程中发生接触。对于采用可变定子叶片的多级轴向压缩机，了解间隙变化对压缩机性能的影响在设计过程中至关重要。本研究的重点是利用真实的发动机结构，对配备了可变定子叶片和排气装置的高压压缩机进行实验研究。研究深入探讨了可变机构流场内的损耗特性和流动机制。结果表明，在雷尼直径相同的情况下，增加径向间隙最初会降低流场损耗，但随后损耗会上升，在间隙为 2 毫米（叶片高度的 1.25%）时达到最小值。相反，在径向间隙相同的情况下，增大分币直径最初会增加损耗，然后减小，分币直径越大，损耗越小。根据这些发现，可以推断出 2 毫米左右的间隙可大大减少叶片内的损耗。叶片高度距内壁 0-10% 范围内的损耗主要来自笔形漏涡及其与通道涡的相互作用，而叶片高度 10-20% 范围内的损耗主要来自通道涡，从而降低了总体损耗。研究表明，与零间隙叶片相比，带有部分间隙的可变定子叶片可降低总压力损失，并实现更好的流场控制。

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引用次数: 0

Fast aerodynamic analysis method for three-dimensional morphing wings based on deep learning 基于深度学习的三维变形机翼快速气动分析方法

IF 5 1区工程技术 Q1 ENGINEERING, AEROSPACE

Aerospace Science and Technology

Pub Date : 2024-10-29 DOI: 10.1016/j.ast.2024.109690

Ruolong Xie , Zhiqiang Wan , De Yan , Wenwei Qiu

Morphing wings have garnered widespread attention due to their superior aerodynamic efficiency. However, in the design process, accurately and efficiently obtaining the three-dimensional flow field of morphing wings remains a challenging issue. This paper proposes a Deep Learning-based method for predicting the flow field of a Biomimetic Morphing Wings to address this problem. Firstly, a Coordinate Transformation Mechanism is established for the studied Biomimetic Morphing Wing to ensure the consistency of grid point coordinates between different wing shapes. Secondly, a two-level Flow Field Prediction Model is constructed, consisting of grid point prediction level and physical quantity continuity adjustment level. Using this method, the flow field of the Biomimetic Morphing Wing was predicted, and the predication result were similar to those of numerical simulations. This indicates that the proposed method maintains high prediction accuracy while reducing computation time, thereby enhancing the analysis efficiency of the morphing wing's flow field.

变形机翼因其卓越的气动效率而受到广泛关注。然而，在设计过程中，准确有效地获取变形翼的三维流场仍然是一个具有挑战性的问题。本文针对这一问题，提出了一种基于深度学习的仿生变形翼流场预测方法。首先，针对所研究的仿生变形翼建立了坐标变换机制，以确保不同翼型之间网格点坐标的一致性。其次，构建了两级流场预测模型，包括网格点预测级和物理量连续性调整级。利用该方法对仿生变形翼的流场进行了预测，预测结果与数值模拟结果相似。这表明所提出的方法在减少计算时间的同时保持了较高的预测精度，从而提高了变形翼流场的分析效率。

引用次数: 0

Closed-loop AI-aided image-based GNC for autonomous inspection of uncooperative space objects 基于图像的闭环人工智能辅助 GNC，用于自主检测不合作的空间物体

IF 5 1区工程技术 Q1 ENGINEERING, AEROSPACE

Aerospace Science and Technology

Pub Date : 2024-10-29 DOI: 10.1016/j.ast.2024.109700

Andrea Brandonisio , Michele Bechini , Gaia Letizia Civardi, Lorenzo Capra, Michèle Lavagna

Autonomy is increasingly crucial in space missions due to several factors driving the exploration and utilization of space. In the meanwhile, Artificial Intelligence methods begin to play a crucial role in addressing the challenges associated with and enhancing autonomy in space missions. The proposed work develops a closed-loop simulator for proximity operations scenarios, particularly for the inspection of an unknown and uncooperative target object, with a fully AI-based image processing and GNC chain. This tool is based on four main blocks: image generation, image processing, navigation filter, and guidance and control blocks. All of them have been separately tested and tuned to ensure the correct interface and compatibility in the close-loop architecture. Afterwards, the overall architecture is deployed in an extensive Montecarlo testing campaign to verify and validate the performance of the proposed IP-GNC loop.

由于空间探索和利用的若干驱动因素，自主性在空间飞行任务中越来越重要。与此同时，人工智能方法开始在应对与空间任务相关的挑战和增强自主性方面发挥关键作用。拟议的工作开发了一个闭环模拟器，用于近距离操作场景，特别是对未知和不合作目标物体的检查，该模拟器具有完全基于人工智能的图像处理和 GNC 链。该工具基于四个主要模块：图像生成、图像处理、导航过滤器以及制导和控制模块。所有这些模块都经过单独测试和调整，以确保闭环架构中的正确接口和兼容性。随后，在广泛的蒙特卡洛测试活动中部署了整体架构，以验证和确认所建议的 IP-GNC 环路的性能。

引用次数: 0

Numerical study of aluminum combustion with agglomerate size distribution in solid rocket motor 固体火箭发动机中带有结块粒度分布的铝燃烧数值研究

IF 5 1区工程技术 Q1 ENGINEERING, AEROSPACE

Aerospace Science and Technology

Pub Date : 2024-10-28 DOI: 10.1016/j.ast.2024.109696

He Chen , Wenjing Yang , Qingyun Sheng , Huangpeng Wang , Yan Ba , Peijin Liu , Wen Ao

The aluminum agglomerate size distribution plays an important role in influencing the particle distributed combustion in motor, which subsequently affects the performance of solid rocket motor significantly. In this work, a three-phase model to describe distributed combustion of aluminum agglomerates is established based on the Eulerian-Lagrangian method. Then, the agglomerate size, including mono size and distributed size, is studied to reveal its effect on aluminum combustion and motor flow field. The simulated results indicate that the increasing agglomerate mono size observes the obvious decrease of the average temperature inside the motor combustion chamber, implying the low combustion efficiency of large agglomerate size. When considering the agglomerate size distribution, the size distribution mode and the mean size D₄₃ determine the combustion efficiency together. In particular, even the mean size is similar, with different distribution mode, like skewed distribution, bimodal or trimodal distribution, the combustion efficiency and flow field parameters are nonnegligible different. However, when the size distribution mode is the same and the peak range is similar, the mean size D₄₃ becomes the only and predominant factor as the mono size.

铝团粒的粒度分布对发动机中的颗粒分布式燃烧有重要影响，进而对固体火箭发动机的性能产生重大影响。本研究基于欧拉-拉格朗日方法，建立了描述铝团粒分布式燃烧的三相模型。然后，研究了团聚体的粒度，包括单粒度和分布粒度，以揭示其对铝燃烧和发动机流场的影响。模拟结果表明，随着结块单粒径的增大，电机燃烧室内的平均温度明显下降，这意味着大粒径结块的燃烧效率较低。在考虑团聚体粒度分布时，粒度分布模式和平均粒度 D43 共同决定了燃烧效率。特别是，即使平均粒度相似，在不同的分布模式下，如偏斜分布、双峰或三峰分布，燃烧效率和流场参数都有不可忽略的差异。然而，当粒度分布模式相同且峰值范围相似时，平均粒度 D43 就会成为唯一且主要的单粒度因素。

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引用次数: 0

Experimental and numerical study on the mechanism of leakage flow influence on the performance of high-speed diffuser cascade 泄漏流对高速扩散器级联性能影响机理的实验和数值研究

IF 5 1区工程技术 Q1 ENGINEERING, AEROSPACE

Aerospace Science and Technology

Pub Date : 2024-10-28 DOI: 10.1016/j.ast.2024.109698

Tianshuo Huang , Xiaozhi Kong , Huawei Lu , Zhengyang Dong , Pengwei Fan

For the purpose of further enhancing the performance of the cascade, this study takes the high-load diffuser cascade as the research object. By simplifying the design of the cascade with leakage flow in experiments, tests and numerical simulation were conducted at design incidence angle of 0° and the minimum loss incidence angle of -4° for different leakage flow rates and leakage inflow angles. The results show that changes in leakage flow rates and inflow angles will lead to variations in the momentum thickness of the boundary layer at the leading edge of the cascade, thereby affecting the cascade performance. Increasing the leakage flow rate results in an increase in the spanwise and tangential momentum of the leakage flow, a thickening in the axial momentum thickness of the boundary layer at the cascade leading edge, a reduction in the static pressure on the endwall within the cascade passage, a decrease in the expansion capability, and a raising in losses. Increasing the leakage inflow angle results in no change in the spanwise momentum of the leakage flow, an increase in the tangential momentum, a thickening in the tangential momentum thickness of the boundary layer at the cascade leading edge, a gradual increase in the static pressure at the leading edge, but a decrease in the static pressure within the cascade passage, leading to a decrease in the expansion capability. Changes in the tangential momentum of the leakage flow mainly affect the passage vortex, the trailing shedding vortex and the concentrated shedding vortex within the cascade passage.

为了进一步提高级联的性能，本研究以高负载扩散器级联为研究对象。通过简化试验中带有泄漏流的级联设计，在设计入射角为 0° 和最小损耗入射角为 -4° 时，针对不同的泄漏流量和泄漏流入角进行了试验和数值模拟。结果表明，泄漏流量和流入角的变化会导致级联前缘边界层动量厚度的变化，从而影响级联性能。增加泄漏流速会导致泄漏流的跨向动量和切向动量增加，级联前缘边界层的轴向动量厚度增厚，级联通道内端壁上的静压降低，膨胀能力下降，损耗增加。增大泄漏流入角会导致泄漏流的跨向动量不变、切向动量增大、级联前缘边界层的切向动量厚度增厚、前缘静压逐渐增大，但级联通道内的静压减小，从而导致膨胀能力减小。泄漏流切向动量的变化主要影响级联通道内的通道漩涡、尾部脱落漩涡和集中脱落漩涡。

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引用次数: 0

Numerical study on the combustion characteristics and performances of single and multi-injectors in a scramjet combustor 关于争气式喷气燃烧器中单喷射器和多喷射器的燃烧特性和性能的数值研究

IF 5 1区工程技术 Q1 ENGINEERING, AEROSPACE

Aerospace Science and Technology

Pub Date : 2024-10-28 DOI: 10.1016/j.ast.2024.109697

Seung-Min Jeong , Jae-Eun Kim , Min-Su Kim , Bu-Kyeng Sung , Jeong-Yeol Choi , Kenneth H. Yu

The present study numerically investigates the combustion characteristics and performance of a direct-connect gaseous hydrogen-fueled scramjet combustor depending on the injector scheme. A comprehensive numerical simulation was conducted with an improved delayed detached eddy simulation (IDDES) approach. The framework utilized a high-order accurate numerical scheme to ensure the high fidelity of the results. A total of ten cases were considered combining two injector schemes and five injection pressure conditions. Each injector scheme had a similar range of global equivalence ratios. Numerical results revealed the differences in the local dynamics of the counter-rotating vortex pair. The multi-injector case did not maintain the jet's systemic vortex structure, which plays a primary role in the fuel-air mixing and burning. It owes to the interactions between the jet-jet and the jet-wall surface, where the interaction leads to the loss of momentum. This characteristic of the multi-injector makes the fuel-air mixing contact surface get closer to a thin-flat layer, resulting in the flame being anchored on a flat shear layer over the entire combustor. As a result, the combustion efficiency of the multi-injector is much lower than that of the single injector under a similar equivalence ratio range. Present results indicate that the multi-injector, which is expected to increase the combustion performance by maximizing the fuel-air contact surface, may operate in contrast to its original anticipation under certain configurations and conditions. It also suggests that optimizing the combustion performance requires careful design of injector distributions considering the distances and interactions between injector-to-injector and injector-to-wall.

本研究以数值方法研究了直连式气态氢燃料喷射燃烧器的燃烧特性和性能，具体取决于喷射器方案。采用改进的延迟分离涡模拟（IDDES）方法进行了全面的数值模拟。该框架采用了高阶精确数值方案，以确保结果的高保真性。结合两种喷射器方案和五种喷射压力条件，共考虑了十种情况。每种喷射器方案的全局等效比范围相似。数值结果显示了反向旋转涡对的局部动力学差异。多喷射器情况下没有保持喷流的系统涡旋结构，而该结构在燃料-空气混合和燃烧中起着主要作用。这是由于射流与射流壁表面之间的相互作用导致了动量的损失。多喷射器的这一特性使燃料与空气的混合接触面更接近于薄平面，从而使火焰固定在整个燃烧器的平面剪切层上。因此，在相似的当量比范围内，多喷射器的燃烧效率远低于单喷射器。目前的结果表明，多喷射器有望通过最大化燃料-空气接触面来提高燃烧性能，但在某些配置和条件下，其运行可能与其最初的预期相反。它还表明，要优化燃烧性能，就必须仔细设计喷油器分布，考虑喷油器与喷油器之间以及喷油器与壁之间的距离和相互作用。

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引用次数: 0

Iterative control framework with application to guidance and attitude control of rockets 应用于火箭制导和姿态控制的迭代控制框架

IF 5 1区工程技术 Q1 ENGINEERING, AEROSPACE

Aerospace Science and Technology

Pub Date : 2024-10-28 DOI: 10.1016/j.ast.2024.109691

Xun Liu, Hashem Ashrafiuon, Sergey G. Nersesov

Traditional control methods for nonlinear dynamical systems are predicated on verification of complex mathematical conditions related to the existence of a positive-definite Lyapunov function whose value must strictly decrease with time. Rigorous verification of Lyapunov conditions can be extremely difficult in real-world systems with high-dimensional and complex dynamics. In this paper, we present a novel control logic that can be readily applied to a general class of nonlinear systems irrespective of the complexities in their dynamics. The Iterative Control Framework (ICF) is designed to guarantee the convergence of the closed-loop system state to zero without a priori verification of Lyapunov-like conditions. The underlying computational routine runs in the background in real time and reconfigures the control vector at each time step in such a way that when the control input is applied to the system, the system trajectory reaches closer to the desired state. The technique is applicable to a broad class of complex nonlinear systems but is particularly suitable for systems inherently admitting control action of short duration such as missiles, rockets, satellites, and space vehicles. In this work, we focus on the application of ICF to guidance and attitude control of rockets and missiles where actuation is provided via single-use thrusters.

非线性动态系统的传统控制方法以验证复杂的数学条件为前提，这些条件与正有限 Lyapunov 函数的存在有关，该函数的值必须随时间严格递减。在具有高维和复杂动态的真实世界系统中，对 Lyapunov 条件进行严格验证极为困难。在本文中，我们提出了一种新颖的控制逻辑，无论非线性系统的动态如何复杂，它都能轻松地应用于一般的非线性系统。迭代控制框架（ICF）旨在保证闭环系统状态收敛为零，而无需事先验证类似 Lyapunov 的条件。底层计算程序在后台实时运行，并在每个时间步重新配置控制矢量，使控制输入应用到系统时，系统轨迹更接近所需的状态。该技术适用于各类复杂的非线性系统，但尤其适用于导弹、火箭、卫星和太空飞行器等固有的允许短时间控制行动的系统。在这项工作中，我们将重点关注 ICF 在火箭和导弹的制导和姿态控制中的应用，在这些系统中，通过一次性推进器提供驱动力。

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引用次数: 0

Non-equilibrium plasma distribution in the wake of a slender blunted-nose cone in hypersonic flight and its effect on the radar cross section 高超音速飞行中细长钝头锥尾流中的非平衡等离子体分布及其对雷达截面的影响

IF 5 1区工程技术 Q1 ENGINEERING, AEROSPACE

Aerospace Science and Technology

Pub Date : 2024-10-28 DOI: 10.1016/j.ast.2024.109699

Salvatore Esposito , Andrea Scarabosio , Giuseppe Vecchi , Domenic D'Ambrosio

This paper presents numerical results in hypersonic aerothermodynamics, a critical field within aerospace engineering, traditionally focusing on reentry capsules and more recently, slender hypersonic vehicles. While capsules typically undergo near-field analysis to assess heat flux and pressure distributions for Thermal Protection System sizing, slender bodies demand additional attention to wake dynamics due to plasma presence. Plasma can significantly affect the Radar Cross Section (RCS) of these vehicles, which require tracking during flight due to their maneuvering and sustained flight capability.

Utilizing Computational Fluid Dynamics tools, we explore plasma distribution around a slender blunted cone, considering altitudes and Mach number regimes that may characterize gliding or sustained atmospheric hypersonic flight, emphasizing its impact on RCS. Our study integrates an aerothermodynamic model incorporating non-equilibrium relaxation equations for gas composition and energy. By evaluating characteristic plasma quantities, we underscore the importance of wake plasma for subsequent electromagnetic wave analysis, crucial for understanding RCS. Furthermore, we highlight the necessity for collaborative efforts between Computational Fluid Dynamics (CFD) and Computational Electro-Magnetics (CEM) disciplines to address this challenging interdisciplinary problem.

本文介绍了高超音速空气热力学的数值结果，这是航空航天工程中的一个重要领域，传统上侧重于返回舱，最近则侧重于细长型高超音速飞行器。返回舱通常需要进行近场分析，以评估热通量和压力分布，从而确定热保护系统的尺寸，而细长飞行器由于等离子体的存在，需要额外关注尾流动力学。等离子体会严重影响这些飞行器的雷达截面（RCS），由于其机动和持续飞行能力，在飞行过程中需要对其进行跟踪。利用计算流体动力学工具，我们探索了细长钝锥体周围的等离子体分布，考虑了滑翔或持续大气高超声速飞行的高度和马赫数状态，强调了等离子体对 RCS 的影响。我们的研究整合了一个空气热力学模型，其中包含气体成分和能量的非平衡弛豫方程。通过评估等离子体的特征量，我们强调了唤醒等离子体对后续电磁波分析的重要性，这对理解 RCS 至关重要。此外，我们还强调了计算流体动力学（CFD）和计算电磁学（CEM）学科合作解决这一具有挑战性的跨学科问题的必要性。

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引用次数: 0