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Aeroacoustic Liner Impedance Metamodel from Simulation and Experimental Data Using Probabilistic Learning

AIAA JOURNAL 2023年第11期61卷 4926-4934页

作者： Sinha, Amritesh Soize, Christian Desceliers, Christophe Cunha, Guilherme Gustave Eiffel Univ MSME UMR 8208 F-77454 Marne La Vallee 2 France Airbus Operat SAS F-31300 Toulouse France

To be able to calculate a parameterized aeroacoustic liner impedance, a robust statistical metamodel is constructed as a function of the frequency and of the control parameters that are the percentage of open area and the sound pressure level. This construction is based on the use of simulated data generated with a computationally expensive aeroacoustic model, which translates to a very small training dataset. This means that the learning process has to be used and the probabilistic learning on manifolds algorithm is chosen. Although the aeroacoustic simulation is conducted on a large aeroacoustic computational model, some approximations are introduced, generating model errors that are taken into account by a probability model in the constructed training dataset. This probability model is calibrated using dimensionless experiments available from the open literature. Despite the fact that only a small amount of data is available, a novel statistical metamodel is successfully developed for which the predictions are consistent. This statistical framework allows for exhibiting a confidence region of the parameterized aeroacoustic liner impedance, which gives an information about the level of uncertainties as a function of the frequency and the control parameters.

关键词： Computational Modeling Sound Pressure Level Cumulative Distribution Function Algorithms and Data Structures computing and informatics Hamiltonian Monte Carlo Probabilistic learning

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Improved Nonlinear Statistical Photocalibration of Photodetectors Without Calibrated Light Sources

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JOURNAL OF AEROSPACE INFORMATION SYSTEMS 2024年第2期21卷 192-197页

作者： Cain, Stephen C. Inst Technol Wright Patterson Air Forc OH 45433 USA

The calibration of charge coupled device arrays is commonly conducted using dark frames. Nonabsolute calibration techniques only measure the relative response of the detectors. A recent attempt at creating a procedure for calibrating a photodetector using the underlying Poisson nature of the photodetection statistics that relied on a nonlinear model was shown to be successful but was highly susceptible to the readout noise present in the measurement. This effort produced the nonlinear statistical nonuniformity calibration (NLSNUC) algorithm, which demonstrated an ability to better model the output of photodetector array elements than similar techniques that relied on a linear model. In this paper, a modified three-point NLSNUC photocalibration procedure is defined that requires only first and second moments of the measurements and allows the response to be modeled using a nonlinear function over the dynamic range of the detector. The modified NLSNUC technique is applied to image data containing a light source with a known output power. Estimates of the number of photoelectrons measured by the detector are shown to be superior to those obtained by the original NLSNUC algorithm as well as other statistical calibration techniques that do not utilize a calibrated light source.

关键词： Photodetector Charge Coupled Device Weather Satellite James Webb Space Telescope Poisson Distribution Satellites computing and informatics Analog to Digital Converters Extrasolar Planet Remote Sensing and Applications

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Prediction for Antiresonant and Extremum Response Frequencies of Undamped Structures

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AIAA JOURNAL 2023年第9期61卷 4126-4139页

作者： Meng, Fanwei Zhu, Jihong Hou, Jie Wang, Bo Ping Northwestern Polytech Univ Sch Mech Engn Xian 710072 Shaanxi Peoples R China Univ Texas Arlington Dept Mech & Aerosp Engn Arlington TX 76019 USA

In this paper, two novel methods for predicting the frequencies for antiresonance and local extrema in the frequency response are presented. The interval searching method is based on the new criterion that takes the double antiresonance phenomenon into consideration. A novel eigenvalue formulation method for which the eigenvalues are those frequencies is also developed. Both methods can be applied to large structure because they only need one eigenvalue analysis. Two numerical examples are presented to demonstrate the effectiveness of the proposed methods.

关键词： Frequency Response Functions Mechanical and Structural Vibrations Beam (Structures) Finite Element Analysis computing and informatics Single Input Single Output System Euler Bernoulli Beams Structural Damage Mechanical Properties Dynamic Analysis

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Scheduling an Agile Multipayload Earth-Observing Satellite

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JOURNAL OF SPACECRAFT AND ROCKETS 2024年第1期61卷 143-156页

作者： Zhang, Wenyuan Zheng, Gangtie Tsinghua Univ Sch Aerosp Engn Beijing 100084 Peoples R China

A highly integrated Earth-observing satellite can possess several maneuverable payloads to perform different missions simultaneously, which brings some challenges to the method of task scheduling. This paper addresses the selection and scheduling problem of an agile satellite with several independently maneuverable optical payloads. Some differences compared to the traditional scheduling problem of agile satellites are presented and considered in a constrained optimization model. A two-stage method is proposed to accomplish the scheduling of the satellite and payloads in different stages. Clusters are generated from preprocessed tasks by a clique partition algorithm, and their centers are used to calculate the pointing direction of the satellite in the first stage. A multiobjective local search algorithm is introduced to schedule tasks in each selected cluster in the second stage. Considering the time-dependent property of the transition time, the problem of determining the start observation time is transformed into linear programming in a proposed insertion operator that guarantees the feasibility of generated solutions. Two types of instances are created and tested to demonstrate the effectiveness of the proposed method, and some analyses are conducted based on the experimental results.

关键词： Search Algorithm Optimization Algorithm Multi Objective Evolutionary Algorithms computing and informatics Computer Graphics Earth Observation Satellite

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Pole Estimation and Optical Navigation Using Circle of Latitude Projections

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JOURNAL OF GUIDANCE CONTROL AND DYNAMICS 2024年第3期47卷 407-416页

作者： Christian, John A. Georgia Inst Technol Atlanta GA 30332 USA Guggenheim Sch Aerosp Engn Atlanta GA 30332 USA

Images of both rotating celestial bodies (e.g., asteroids) and spheroidal planets with banded atmospheres (e.g., Jupiter) can contain features that are well-modeled as a circle of latitude (CoL). At large distances, the projections of these CoLs appear as ellipses in images collected by cameras or telescopes onboard exploration spacecraft. This work shows how CoL projections may be used to determine the pole orientation and covariance for a spinning asteroid. In the case of a known planet modeled as an oblate spheroid, it is shown how similar CoL projections may be used for spacecraft localization. These methods are developed using the principles of projective geometry. Numerical results are provided for simulated images of asteroid Bennu (for pole orientation) and of Jupiter (for spacecraft localization).

关键词： Asteroids Gas Giant Telescopes Planetary Science and Exploration Statistical Analysis Monte Carlo Analysis Image Processing Shape Reconstruction computing and informatics Hydrostatic Equilibrium

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Hierarchy of Quadratic Lyapunov Functions for Linear Time-Varying and Related Systems

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JOURNAL OF GUIDANCE CONTROL AND DYNAMICS 2024年第4期47卷 597-608页

作者： Abdelraouf, Hassan Feron, Eric Klett, Corbin Abate, Matthew Coogan, Samuel Univ Illinois Aerosp Engn Champaign IL 61820 USA King Abdullah Univ Sci & Technol Dept Comp Elect & Math Sci & Engn Thuwal 239556900 Saudi Arabia Georgia Inst Technol Sch Aerosp Engn Atlanta GA 30332 Georgia Georgia Inst Technol Sch Elect & Comp Engn Atlanta GA 30332 USA Georgia Inst Technol Sch Elect & Comp Engn Sch Civil & Environm Engn Atlanta GA 30332 USA

A method for constructing homogeneous polynomial Lyapunov functions is presented for linear time-varying or switched-linear systems and the class of nonlinear systems that can be represented as such. The method uses a simple recursion based on the Kronecker product to generate a hierarchy of related dynamical systems, whose first element is the system under study and the second element is the well-known Lyapunov differential equation. It is then proven that a quadratic Lyapunov function for the system at one level in the hierarchy, which can be found via semidefinite programming, is a homogeneous polynomial Lyapunov function for the system at the base level in the hierarchy. Searching for Lyapunov functions of the foregoing kind is equivalent to searching for homogeneous polynomial Lyapunov functions via the formulation of sum-of-squares programs. The quadratic perspective presented in this paper enables the easy development of procedures to compute bounds on pointwise-in-time system metrics, such as peak norms, system stability margins, and many other performance measures. The applications of the theory to analyzing an aircraft model, on the one hand, and an experimental aerospace vehicle, on the other hand, are presented. The theory can be comprehended with a first course on state-space control systems and an elementary knowledge of convex programming.

关键词： Aerospace Control System Applied Mathematics computing and informatics Lyapunov Stability Theory Aerospace Sciences Mathematical Optimization Quadcopter Drag Coefficient Aircraft Flight Control System Atmospheric Science

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Level-Set Mass-Conservative Front-Tracking Technique for Multistep Simulations of In-Flight Ice Accretion

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JOURNAL OF AIRCRAFT 2023年第4期60卷 1050-1060页

作者： Donizetti, Alessandro Bellosta, Tommaso Rausa, Andrea Re, Barbara Guardone, Alberto Polytech Univ Milan Dept Aerosp Sci & Technol I-20156 Milan Italy

This paper presents a novel level-set-based approach to model evolving boundary problems for in-flight ice accretion. No partial differential equations are solved as in the standard level-set formulation, but simple geometrical quantities are employed to provide an implicit discretization of the updated boundary. This method avoids mesh entanglements and grid intersections typical of algebraic and mesh deforming techniques, making it suitable for generating a body-fitted discretization of arbitrarily complex geometries as in-flight ice shapes, including the collision of separate ice fronts. Moreover, this paper presents a local ice thickness correction, which accounts for the body's curvature, to conserve the prescribed iced mass locally. The verification includes ice accretion over an ellipse and a manufactured example to show the proposed strategy's advantages and robustness compared to standard algebraic methods. Finally, the method is applied to ice accretion problems. A temporal and grid convergence study is presented for automatic multistep in-flight simulations over a NACA0012 airfoil in rime, glaze, and mixed ice conditions.

关键词： NACA 23012 Aviation Weather Hazards Flight Simulation computing and informatics Reynolds Averaged Navier Stokes Numerical Interpolation Aerodynamic Performance Computational Fluid Dynamics Aerodynamic Simulation Thermodynamic Process

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Accuracy of the Newton and Newton-Lees Theories in Space Application

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JOURNAL OF SPACECRAFT AND ROCKETS 2023年第3期60卷 1039-1042页

作者： Zuppardi, Gennaro Mongelluzzo, Giuseppe Univ Naples Federico II Hyperson Aerodynam I-80125 Naples Italy Italian Natl Inst Astrophys Astron Observ Capodimonte I-80131 Naples Italy

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Mistuning Identification of Blisks Using Mass Detuning and Influence Coefficients

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AIAA JOURNAL 2023年第8期61卷 3682-3691页

作者： Cimpuieru, Mihai Kelly, Sean T. T. Lupini, Andrea Keener, Christopher D'Souza, Kiran Epureanu, Bogdan I. I. Univ Michigan Dept Mech Engn Ann Arbor MI 48109 USA Ohio State Univ Dept Mech & Aeronaut Engn Columbus OH 43210 USA

Integrally bladed disks, also known as blisks, are important components in the operation of gas turbines. To study the dynamics of these structures, several computational techniques approximate blisks as tuned systems, where all blades have the same characteristics. In reality, manufactured blades have small variations from their intended design, thus creating so-called mistuned systems. Previous work has shown that such small variations can cause high response amplifications that can result in blisk structural failure. Therefore, it is essential to identify mistuning to ensure the safe operation of these systems. Several methods utilize cantilever blade frequencies in their procedure to model mistuning and calculate blisk vibration response. A previously developed mistuning identification method uses mass detuning to isolate the cantilever blade frequencies and a set of influence coefficients to quantify the blade-to-blade couplings. However, the mistuning is calculated with respect to an arbitrary mistuning value that later needs to be identified through a trial-and-error procedure that can affect the accuracy of the final mistuning values. This paper focuses on updating the method to eliminate this additive error that cannot precisely be determined. Furthermore, the updated procedure is applied to an as-manufactured blisk using experimental ping test results. An additional analysis is performed on the effect of adding multiple sets of influence coefficients to capture the blade-to-blade couplings more accurately.

关键词： Gas Turbine Mechanical Properties computing and informatics Structural Dynamics Nonlinear Dynamics Turbomachinery Modal Analysis Aircraft Engines Vibration Isolation Structural Dynamics and Characterization

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Quantum Networks: A New Platform for Aerospace

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AIAA JOURNAL 2024年第9期62卷 3196-3207页

作者： Brickman Soderberg, Kathy-Anne Gauthier, Daniel J. Kwiat, Paul G. Srinivas, Raghavendra Air Force Res Lab Quantum Sci & Technol Informat Directorate Rome NY 13441 USA Ohio State Univ Dept Phys Columbus OH 43210 USA Univ Illinois Phys Champaign IL 61820 USA Univ Illinois Illinois Quantum Informat Sci & Technol Ctr Dept Phys Champaign IL 61820 USA Univ Oxford Dept Phys Clarendon Lab Parks Rd Oxford OX1 3PU England

The ability to distribute entanglement between quantum nodes may unlock new capabilities in the future that include teleporting information across multinode networks, higher resolution detection via entangled sensor arrays, and measurements beyond the quantum limit enabled by networked atomic clocks. These new quantum networks also hold promise for the Aerospace community in areas such as deep space exploration, improved satellite communication, and synchronizing drone swarms. Although exciting, these applications are a long way off from providing a "real-world" benefit, as they have only been theoretically explored or demonstrated in small-scale experiments. An outstanding challenge is to identify near-term use cases for quantum networks;this may be an intriguing new area of interest for the aerospace community, as the quantum networking field would benefit from more multidisciplinary collaborations. This paper introduces quantum networking, discusses the difficulties in distributing entanglement within these networks, highlights recent progress toward this endeavor, and features two current case studies on mobile quantum nodes and an entangled clock network, both of which are relevant to the aerospace community.

关键词： Aerospace Sciences Optical Sensor Satellite Swarm Unmanned Aerial Vehicle Space Exploration and Technology computing and informatics Telescopes Wireless Communications Very Long Baseline Interferometry Research Facilities and Instrumentation

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