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AIAA Science and Technology Forum and Exposition (AIAA SciTech)

作者： Martins, Joaquim R. R. A. Univ Michigan Dept Aerosp Engn Ann Arbor MI 48109 USA

ISBN: (数字)9781624105951

ISBN: (纸本)9781624105951

CFD-based aircraft design optimization has matured significantly in the last few years thanks to improvements in CFD solvers, mesh deformation, sensitivity computation, and optimization tools. We review our recent developments for each of these components, and present open-source tools made available for aerodynamic shape optimization. Avariety of applications is presented, including the optimization of a supercritical airfoil starting from a circle, a web application that optimizes airfoils within a few seconds, aircraft aerodynamic and aerostructural optimization, and aeropropulsive optimization. We also review our experience with solving the Aerodynamic Design Optimization Discussion Group (ADODG) benchmarks and other problems in aerodynamic shape optimization. Among the ADODG benchmarks, we focus on the RANS-based problems and discuss some of the issues encountered, including the comparison between Euler and RANS results, and design space multimodality. The availability of these benchmarks and the open-source tools is expected to enable further studies and benchmarks in CFD-based aerodynamic design optimization and MDO.

关键词： Aerodynamic Force Coefficients Multidisciplinary Design Optimization Aircraft Design Supercritical Airfoils Lift Coefficient Aircraft Configurations sequential quadratic programming Shape Optimization FORTRAN Gradient Free Optimization

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Shape Optimization of Vortex Generators to Control Mack Mode Amplification

Shape Optimization of Vortex Generators to Control Mack Mode...

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AIAA Aviation Forum

作者： Pederson, Clark C. Choudhari, Meelan M. Zhou, Beckett Y. Parede, Pedro Disking, Boris Univ Texas Austin Walker Dept Mech Engn Austin TX 78712 USA NASA Langley Res Ctr Computat AeroSci Branch Hampton VA 23681 USA TU Kaiserslautern Chair Sci Comp Bldg 34Paul Ehrlich Str D-67663 Kaiserslautern Germany NIA Computat AeroSci Branch Hampton VA 23681 USA NIA Hampton VA 23681 USA

ISBN: (数字)9781624105982

ISBN: (纸本)9781624105982

This paper demonstrates the potential to use shape optimization for the design of vortex generators in an axisymmetric boundary layer. This shape optimization increases the amplitude of stationary streaks created by streamwise vorticity, with the goal of reducing the amplification of Mack mode instabilities. The test case under consideration matches a trajectory point during the ascent phase of the HIFiRE-1 flight experiment. Wall-mounted vortex generators are added to the cone and their shape is optimized to control the amplification of Mack mode instabilities that are known to initiate laminar-turbulent transition in this flow. An empirical objective function is developed based on the previous studies of optimal streaks. A constraint on the maximum streak amplitude is added to avoid the initiation of bypass transition. The shape optimization is conducted using SU2, an open-source suite for multiphysics simulation and design. A significant improvement is observed in an integral metric of the streak amplitude, while the maximum streak amplitude is maintained close to the baseline level. The qualitative features of the optimized geometry are discussed.

关键词： Vortex Generators Shape Optimization Laminar Turbulent Transition Tollmien Schlichting waves Direct Numerical Simulation Freestream Mach Number sequential quadratic programming Hypersonic Flows Navier Stokes Equations Lagrange Multipliers

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Objectives and Constraints for Transonic Wing Optimization

Objectives and Constraints for Transonic Wing Optimization

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AIAA Science and Technology Forum and Exposition (AIAA SciTech)

作者： Poole, D. J. Allen, C. B. Rendall, T. C. S. Univ Bristol Dept Aerosp Engn Bristol BS8 1TR Avon England Univ Bristol Dept Aerosp Engn Computat Aerodynam Bristol BS8 1TR Avon England

ISBN: (数字)9781624105951

ISBN: (纸本)9781624105951

Consideration of the aerodynamic shape optimization problem definition is presented. An issue with drag minimization is that shocked-free solutions often result which have isolated performance improvements. As such, in this paper, optimizing the range parameter is considered enriched with the operating point as a design variable. A constraint on dimensional lift is therefore required. Analytical treatment of this problem is used to demonstrate that supercritical solutions result providing the lift is above a critical threshold. Also, three-dimensional effects penalise lift coefficient and promote higher optimum Mach numbers. Single- and multi-point optimizations of the NASA CRM wing are considered, inspired by the AIAA ADODG Case 4, as well as a range optimization. A shocked solution is found for the range optimization.

关键词： Aerodynamic Shape Optimization Lift Coefficient Multi Point Optimization Reynolds Averaged Navier Stokes sequential quadratic programming Transonic Flow Aspect Ratio Wing Loading Computational Fluid Dynamics Aircraft Design

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Direct numerical solution of a time-optimal state-constrained control problem in a flow 7

Direct numerical solution of a time-optimal state-constraine...

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7th International Conference on Control, Decision and Information Technologies (CoDIT)

作者： Chertovskih, Roman Pereira, Fernando Lobo Univ Porto Fac Engn Res Ctr Syst & Technol SYSTEC Elect & Comp Engn Dept Porto Portugal

ISBN: (纸本)9781728159539

We consider the following time-optimal control problem with state constraints: compute minimal travelling time of a controllable object moving in a prescribed flow field in a bounded domain between two given points. The optimal control problem is solved numerically using two direct methods interior-point line search filter method and sequential quadratic programming. Five sample flows are considered, and computational properties of the corresponding simulations are measured and discussed.

关键词： optimal control direct methods interior-point method sequential quadratic programming

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Nonlinear Model Predictive Control and Collision-Cone-Based Missile Guidance Algorithm

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JOURNAL OF GUIDANCE CONTROL AND DYNAMICS 2021年第8期44卷 1481-1497页

作者： Bhattacharjee, Diganta Chakravarthy, Animesh Subbarao, Kamesh Univ Texas Arlington Dept Mech & Aerosp Engn Box 19018 Arlington TX 76019 USA

In this paper, a hybrid missile guidance algorithm is proposed for planar engagement scenarios. The method combines nonlinear model predictive control (NMPC) with a collision cone approach, and enables the guidance algorithm to achieve interception, while ensuring that the impact angle lies in a predefined range. The guidance scheme comprises two components: 1) point-mass-based NMPC and 2) collision-cone-based NMPC. The point-mass-based NMPC is employed when the distance between the missile and the target is large, and when this distance falls below a threshold, the algorithm switches to a collision-cone-based NMPC. Connections between the impact angle and the collision cone are theoretically established, and these are used in the collision-cone-based NMPC. The NMPC problems are formulated as quadratic programs that include appropriate constraints on the states and inputs, while not requiring target acceleration information. These quadratic programs are shown to be strictly convex. Detailed simulations are performed to demonstrate the effectiveness of the proposed approach.

关键词： Guidance Algorithms Model Predictive Control sequential quadratic programming Terminal Guidance Control Guidance Heading Angle Optimal Control Engagement Kinematics Warheads Convex Optimization

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Parameter Identification for a 3D Heating Process by the Adjoint Method based on Experimental Data

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IFAC-PapersOnLine 2021年第11期54卷 103-108页

作者： Dirk Wolfram Thomas Meurer Chair of Automatic Control Faculty of Engineering Kiel University 24143 Kiel Germany

Model-based control of systems governed by partial differential equations relies on the knowledge of the model parameters. Their determination is complicated by the spatial-temporal process dynamics. In addition the interaction of the process and the (embedded) actuation devices might be subject to uncertainties. This work applies a late-lumping approach for parameter identification given a 3-dimensional heat conduction and heat transfer problem with actuation dynamics represented by a coupled PDE-ODE model. By defining a suitable minimization problem the necessary optimality conditions in terms of adjoint PDE-ODE couplings are determined using variational calculus. In additional gradient information can be directly extracted that is used in course of the numerical evaluation by making use of sequential quadratic programming. For this the Finite-Element method is applied for the forward solution of the model equations and backward solution of the adjoint equations. Data collected at the experimental realization of 3-dimensional heating process for different actuation scenarios is used for evaluation and comparison.

关键词： Parameter identification Heat equation Adjoint Method Actuator dynamics Optimization Finite Element Method Partial Differential Equations sequential quadratic programming

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Aerodynamic Shape Optimization for Unsteady Flows: Some Benchmark Problems

Aerodynamic Shape Optimization for Unsteady Flows: Some Benc...

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AIAA Science and Technology Forum and Exposition (AIAA SciTech)

作者： Apponsah, Kwesi P. Zingg, David W. Univ Toronto Inst Aerosp Studies Toronto ON M3H 5T6 Canada Univ Toronto Inst Aerosp Studies Computat Aerodynam & Sustainable Aviat Toronto ON M3H 5T6 Canada Univ Toronto Inst Aerosp Studies Ctr Res Sustainable Aviat Toronto ON M3H 5T6 Canada Univ Toronto Inst Aerosp Studies Ctr Computat Sci & Engn Toronto ON M3H 5T6 Canada

ISBN: (数字)9781624105951

ISBN: (纸本)9781624105951

We present an efficient aerodynamic shape optimization framework for optimization problems under unsteady flow conditions. The optimization framework consists of a parallel Newton-Krylov flow solver for multi-block grids and an integrated geometry parameterization and mesh-deformation algorithm based on linear elasticity. We apply the adjoint method to the discretized governing equations to compute the gradients required by the sequential quadratic programming optimization algorithm. We propose two lift-constrained drag minimization problems for the purposes of testing and evaluating the framework. First, we consider a laminar flow airfoil optimization problem at a Reynolds number of 800 and also investigate the convexity of the optimization problem. We show that the optimizer is capable of reducing the drag for this problem by about 23% and produces a nearly steady flow compared to the vortex shedding observed for the baseline geometry at the required lift target. The second benchmark case is a lift-constrained drag minimization of an aspect ratio eight rectangular wing in a laminar flow at a Reynolds number of 800. Section shape, twist, and angle of attack are free. Although only partially converged at the time of writing, the preliminary results show a 20% drag reduction.

关键词： Aerodynamic Shape Optimization Flow Conditions Lift Coefficient Airfoil Vortex Shedding sequential quadratic programming Aspect Ratio Lift to Drag Ratio Linear Elasticity Computational Fluid Dynamics

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Direct Methods Comparison for the Active Target Defense Scenario

Direct Methods Comparison for the Active Target Defense Scen...

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AIAA Science and Technology Forum and Exposition (AIAA SciTech)

作者： Weintraub, Isaac E. Cobb, Richard Baker, William Pachter, Meir US Air Force Res Lab Wright Patterson AFB OH 45433 USA US Air Force Res Lab Dept Aerosp Engn Wright Patterson AFB OH 45433 USA US Air Force Res Lab Dept Mathemat Wright Patterson AFB OH 45433 USA US Air Force Res Lab Dept Elect Engn Wright Patterson AFB OH 45433 USA

ISBN: (数字)9781624105951

ISBN: (纸本)9781624105951

The goal of optimal control is to obtain an admissible function which minimizes an objective functional subject to specified constraints and boundary conditions. Four popular methods of computing the optimal control directly are the Single Shooting Method, Multiple Shootings Method, Even Collocation Method, and Pseudospectral Method. In this paper, the four direct methods of computing the optimal control for the Active Target Defense Scenario are presented and compared. The Active Target Defense Scenario is a three-agent engagement where an evading agent tries to escape a pursuing agent with the assistance of a defending agent. The goal of the Evader is to maneuver in such a way as to assist the Defender in capturing the Pursuer while maximizing his range from the Pursuer. This work begins by describing each direct method and summarizing advantages and disadvantages of each. Next, each method is used to solve the optimal control for the Active Target Defense Scenario;results are presented and a comparison of the performance of each method is made. Finally, concluding remarks describing the results, performance, and real-time implementation are presented.

关键词： Optimal Control Theory Gaussian Quadrature Pseudospectral Methods Parallel Computing Techniques Nonlinear programming sequential quadratic programming Heading Angle Proportional Navigation Runge Kutta Methods MATLAB

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Multi-Fidelity Wing Optimization Utilizing 2D to 3D Pressure Distribution Mapping in Transonic Conditions

Multi-Fidelity Wing Optimization Utilizing 2D to 3D Pressure...

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AIAA Science and Technology Forum and Exposition (AIAA SciTech)

作者： MacDonald, Timothy Alonso, Juan J. Stanford Univ Dept Aeronaut & Astronaut Stanford CA 94305 USA

ISBN: (数字)9781624105951

ISBN: (纸本)9781624105951

Due to time and resource constraints, the conceptual design process for new aircraft is typically limited to inexpensive low-fidelity methods. Unfortunately, these methods generally only provide the fidelity necessary to confidently go forward with a new design when they have been calibrated to previous aircraft of similar type. This substantially limits the application of new technology early in the design cycle, and means that only high-level information can be obtained, potentially limiting the available design space. To remedy this, new methods must be developed that can produce higher-fidelity results without a significant increase in cost. Here, we demonstrate a method for higher-fidelity aerodynamic analysis that incorporates 2D and 3D pressure distribution mapping into a multi-fidelity framework. This expands on previous work in the area by providing a multi-fidelity approach that allows for the prediction of the shape of the pressure distribution in addition to high level aerodynamic performance. As part of this demonstration, we present results for a wing that has been optimized using the 3D solver FLO107 exclusively, as well as a combination of the 2D solver FLO103 and FLO107. The differences in required evaluations and the final results are documented.

关键词： Aerodynamic Performance Skin Friction Aerodynamic Shape Optimization Supercritical Airfoils Linear Interpolation Transonic Flow sequential quadratic programming Thickness to Chord Ratio Shape Optimization Swept Wing

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Steady-Straight-Level Flight Study: A Mathematical Optimization Approach and Flight Test

Steady-Straight-Level Flight Study: A Mathematical Optimizat...

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AIAA Aviation Forum

作者： Salahuddeni Ghosh, Ajoy Kanti Indian Inst Technol Kanpur Aerosp Engn Kanpur 208016 Uttar Pradesh India

ISBN: (数字)9781624105982

ISBN: (纸本)9781624105982

In this paper, an experiment based thrust control command expression for propeller-driven-piston-engine powered aircraft is obtained to complete the required dynamics for finding the trim flight solutions in steady-straight-level (SSL) condition using a nonlinear optimization technique. sequential quadratic programming (SQP) is adapted to compute the angle-of-attack, sideslip angle and bank angle for a specified flight velocity, turn-radius, and flight path angle of an aircraft which is further utilized to evaluate the trim states and control inputs in SSL flight. Both aerodynamic and thrust control inputs are calculated by the steady-state solution of equations of motion of aircraft. As per the novelty of the present study concern, the flight test is performed on Hansa-3 aircraft at the airfield of IIT Kanpur to model the thrust input as well as to verify the numerical results. Additionally, through the numerical analysis, it is observed that the SQP method economizes the computation time as compared to a gradient descent approach method.

关键词： Flight Testing Pitch Yaw Stability Mathematical Optimization Elevator Deflection sequential quadratic programming Propellers Aerodynamic Moments Flight Path Angle Angle of Sideslip Lagrange Multipliers

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