The Experts below are selected from a list of 21756 Experts worldwide ranked by ideXlab platform

Joaquim R R A Martins - One of the best experts on this subject based on the ideXlab platform.

  • rans based aerodynamic shape optimization of a strut braced wing with overset meshes
    Journal of Aircraft, 2019
    Co-Authors: Ney R Secco, Joaquim R R A Martins
    Abstract:

    The strut-braced wing Aircraft Configuration promises to reduce fuel burn by enabling higher spans that reduce lift-induced drag. A successful design for this Configuration depends on a careful tra...

  • Aerodynamic Design Optimization Studies of a Blended-Wing-Body Aircraft
    Journal of Aircraft, 2014
    Co-Authors: Joaquim R R A Martins
    Abstract:

    The blended wing body is an Aircraft Configuration that has the potential to be more efficient than conventional large transport Aircraft Configurations with the same capability. However, the design of the blended wing is challenging due to the tight coupling between aerodynamic performance, trim, and stability. Other design challenges include the nature and number of the design variables involved, and the transonic flow conditions. To address these issues, a series of aerodynamic shape optimization studies using Reynolds-averaged Navier–Stokes computational fluid dynamics with a Spalart–Allmaras turbulence model is performed. A gradient-based optimization algorithm is used in conjunction with a discrete adjoint method that computes the derivatives of the aerodynamic forces. A total of 273 design variables—twist, airfoil shape, sweep, chord, and span—are considered. The drag coefficient at the cruise condition is minimized subject to lift, trim, static margin, and center plane bending moment constraints. ...

  • scalable parallel approach for high fidelity steady state aeroelastic analysis and adjoint derivative computations
    AIAA Journal, 2014
    Co-Authors: Gaetan K W Kenway, Graeme J Kennedy, Joaquim R R A Martins
    Abstract:

    Aeroelastic systems achieve the best performance when the aerodynamic shape and structural sizing are optimized concurrently, but such an optimization is challenging when high-fidelity aerodynamic and structural models are required. This paper addresses this challenge through several significant improvements. Fully coupled Newton–Krylov methods are presented for the solution of aerostructural systems and for the corresponding adjoint systems. The coupled adjoint method presented can compute gradients with respect to thousands of multidisciplinary design variables accurately and efficiently. This is enabled by several improvements in the computation of the multidisciplinary terms in the coupled adjoint. The parallel scalability of the methods is demonstrated for a full Aircraft Configuration using an Euler computational fluid dynamics model with more than 8×106 state variables and a detailed structural finite element model of the wing with more than 1×106 degrees of freedom. The coupled Newton–Krylov metho...

  • scalable parallel approach for high fidelity steady state aeroelastic analysis and adjoint derivative computations
    AIAA Journal, 2014
    Co-Authors: Gaetan K W Kenway, Graeme J Kennedy, Joaquim R R A Martins
    Abstract:

    Aeroelastic systems achieve the best performance when the aerodynamic shape and structural sizing are optimized concurrently, but such an optimization is challenging when high-fidelity aerodynamic and structural models are required. This paper addresses this challenge through several significant improvements. Fully coupled Newton–Krylov methods are presented for the solution of aerostructural systems and for the corresponding adjoint systems. The coupled adjoint method presented can compute gradients with respect to thousands of multidisciplinary design variables accurately and efficiently. This is enabled by several improvements in the computation of the multidisciplinary terms in the coupled adjoint. The parallel scalability of the methods is demonstrated for a full Aircraft Configuration using an Euler computational fluid dynamics model with more than 8×106 state variables and a detailed structural finite element model of the wing with more than 1×106 degrees of freedom. The coupled Newton–Krylov metho...

  • multi point multi mission high fidelity aerostructural optimization of a long range Aircraft Configuration
    12th AIAA Aviation Technology Integration and Operations (ATIO) Conference and 14th AIAA ISSMO Multidisciplinary Analysis and Optimization Conference;, 2012
    Co-Authors: Rhea Patricia Liem, Gaetan K W Kenway, Joaquim R R A Martins
    Abstract:

    In this paper we present a new robust approach to produce efficient Aircraft using numerical optimization. Our focus is on performing a multi-point optimization that considers the performance at multiple operating points simultaneously. The goal is to avoid severe performance degradation at off-design conditions, which typically occurs with a single-point optimization. Specifically, we aim to design a fuel-efficient long-range Aircraft Configuration. The robustness is introduced by considering hundreds of missions within the operational flight envelope of similar sized Aircraft, based on historical data for the actual flight operations. Due to the large computational cost associated with the high-fidelity multidisciplinary analysis, kriging surrogate models are employed to allow thousands of detailed flight analyses to be performed while limiting the number of high-fidelity evaluations. The methodology is demonstrated in a fuel burn minimization problem of a long-range wide-body Aircraft Configuration.

Bhat M Seetharama - One of the best experts on this subject based on the ideXlab platform.

  • 75-mm Wingspan Fixed-Wing Nano Air Vehicle With a Novel Aircraft Configuration
    IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 2018
    Co-Authors: Pushpangathan Jinraj, Kandath Harikumar, Bhat M Seetharama
    Abstract:

    The development of a fixed-wing nano air vehicle that fits inside a cube of 75 mm is described in this paper. A novel Aircraft Configuration that satisfies the static and dynamic stability and the mission performance requirements is developed. A performance index is formulated to identify a suitable airfoil as there does not exist a single airfoil that achieves the mission required specifications. Eppler-61 is identified as the suitable airfoil since the value of its performance index is maximum among other airfoils selected for the analysis. The static stability of the nano air vehicle is analyzed using the aerodynamic characteristics obtained from the wind tunnel tests. The outcomes of this analysis indicate that the vehicle is statically stable. The analysis also indicates significant aerodynamic cross-coupling between longitudinal and lateral aerodynamic coefficients. The dynamic stability analysis indicates that the nano air vehicle is dynamically stable. Furthermore, the dynamic stability of the vehicle is validated by flight test results

  • 75-mm wingspan fixed-wing nano air vehicle with a novel Aircraft Configuration
    'Institute of Electrical and Electronics Engineers (IEEE)', 2018
    Co-Authors: Pushpangathan Jinraj, Kandath Harikumar, Bhat M Seetharama
    Abstract:

    The development of a fixed-wing nano air vehicle that fits inside a cube of 75 mm is described in this paper. A novel Aircraft Configuration that satisfies the static and dynamic stability and the mission performance requirements is developed. A performance index is formulated to identify a suitable airfoil as there does not exist a single airfoil that achieves the mission required specifications. Eppler-61 is identified as the suitable airfoil since the value of its performance index is maximum among other airfoils selected for the analysis. The static stability of the nano air vehicle is analyzed using the aerodynamic characteristics obtained from the wind tunnel tests. The outcomes of this analysis indicate that the vehicle is statically stable. The analysis also indicates significant aerodynamic cross-coupling between longitudinal and lateral aerodynamic coefficients. The dynamic stability analysis indicates that the nano air vehicle is dynamically stable. Furthermore, the dynamic stability of the vehicle is validated by flight test results.Published versio

Gaetan K W Kenway - One of the best experts on this subject based on the ideXlab platform.

  • scalable parallel approach for high fidelity steady state aeroelastic analysis and adjoint derivative computations
    AIAA Journal, 2014
    Co-Authors: Gaetan K W Kenway, Graeme J Kennedy, Joaquim R R A Martins
    Abstract:

    Aeroelastic systems achieve the best performance when the aerodynamic shape and structural sizing are optimized concurrently, but such an optimization is challenging when high-fidelity aerodynamic and structural models are required. This paper addresses this challenge through several significant improvements. Fully coupled Newton–Krylov methods are presented for the solution of aerostructural systems and for the corresponding adjoint systems. The coupled adjoint method presented can compute gradients with respect to thousands of multidisciplinary design variables accurately and efficiently. This is enabled by several improvements in the computation of the multidisciplinary terms in the coupled adjoint. The parallel scalability of the methods is demonstrated for a full Aircraft Configuration using an Euler computational fluid dynamics model with more than 8×106 state variables and a detailed structural finite element model of the wing with more than 1×106 degrees of freedom. The coupled Newton–Krylov metho...

  • scalable parallel approach for high fidelity steady state aeroelastic analysis and adjoint derivative computations
    AIAA Journal, 2014
    Co-Authors: Gaetan K W Kenway, Graeme J Kennedy, Joaquim R R A Martins
    Abstract:

    Aeroelastic systems achieve the best performance when the aerodynamic shape and structural sizing are optimized concurrently, but such an optimization is challenging when high-fidelity aerodynamic and structural models are required. This paper addresses this challenge through several significant improvements. Fully coupled Newton–Krylov methods are presented for the solution of aerostructural systems and for the corresponding adjoint systems. The coupled adjoint method presented can compute gradients with respect to thousands of multidisciplinary design variables accurately and efficiently. This is enabled by several improvements in the computation of the multidisciplinary terms in the coupled adjoint. The parallel scalability of the methods is demonstrated for a full Aircraft Configuration using an Euler computational fluid dynamics model with more than 8×106 state variables and a detailed structural finite element model of the wing with more than 1×106 degrees of freedom. The coupled Newton–Krylov metho...

  • Multipoint High-Fidelity Aerostructural Optimization of a Transport Aircraft Configuration
    Journal of Aircraft, 2014
    Co-Authors: Gaetan K W Kenway
    Abstract:

    This paper presents multipoint high-fidelity aerostructural optimizations of a long-range wide-body transonic transport Aircraft Configuration. The aerostructural analysis employs Euler computational fluid dynamics with a 2-million-cell mesh and a structural finite-element model with 300,000 degrees of freedom. The coupled adjoint sensitivity method is used to efficiently compute gradients, enabling the use of gradient-based optimization with respect to hundreds of aerodynamic shape and structural sizing variables. The NASA Common Research Model is used as the baseline Configuration, together with a wing box structure that was designed for this study. Two design optimization problems are solved: one where takeoff gross weight is minimized, and another where fuel burn is minimized. Each optimization uses a multipoint formulation with five cruise conditions and two maneuver conditions. Each of the optimization problems have 476 design variables, including wing planform, airfoil shape, and structural thickne...

  • multi point multi mission high fidelity aerostructural optimization of a long range Aircraft Configuration
    12th AIAA Aviation Technology Integration and Operations (ATIO) Conference and 14th AIAA ISSMO Multidisciplinary Analysis and Optimization Conference;, 2012
    Co-Authors: Rhea Patricia Liem, Gaetan K W Kenway, Joaquim R R A Martins
    Abstract:

    In this paper we present a new robust approach to produce efficient Aircraft using numerical optimization. Our focus is on performing a multi-point optimization that considers the performance at multiple operating points simultaneously. The goal is to avoid severe performance degradation at off-design conditions, which typically occurs with a single-point optimization. Specifically, we aim to design a fuel-efficient long-range Aircraft Configuration. The robustness is introduced by considering hundreds of missions within the operational flight envelope of similar sized Aircraft, based on historical data for the actual flight operations. Due to the large computational cost associated with the high-fidelity multidisciplinary analysis, kriging surrogate models are employed to allow thousands of detailed flight analyses to be performed while limiting the number of high-fidelity evaluations. The methodology is demonstrated in a fuel burn minimization problem of a long-range wide-body Aircraft Configuration.

Pushpangathan Jinraj - One of the best experts on this subject based on the ideXlab platform.

  • 75-mm Wingspan Fixed-Wing Nano Air Vehicle With a Novel Aircraft Configuration
    IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 2018
    Co-Authors: Pushpangathan Jinraj, Kandath Harikumar, Bhat M Seetharama
    Abstract:

    The development of a fixed-wing nano air vehicle that fits inside a cube of 75 mm is described in this paper. A novel Aircraft Configuration that satisfies the static and dynamic stability and the mission performance requirements is developed. A performance index is formulated to identify a suitable airfoil as there does not exist a single airfoil that achieves the mission required specifications. Eppler-61 is identified as the suitable airfoil since the value of its performance index is maximum among other airfoils selected for the analysis. The static stability of the nano air vehicle is analyzed using the aerodynamic characteristics obtained from the wind tunnel tests. The outcomes of this analysis indicate that the vehicle is statically stable. The analysis also indicates significant aerodynamic cross-coupling between longitudinal and lateral aerodynamic coefficients. The dynamic stability analysis indicates that the nano air vehicle is dynamically stable. Furthermore, the dynamic stability of the vehicle is validated by flight test results

  • 75-mm wingspan fixed-wing nano air vehicle with a novel Aircraft Configuration
    'Institute of Electrical and Electronics Engineers (IEEE)', 2018
    Co-Authors: Pushpangathan Jinraj, Kandath Harikumar, Bhat M Seetharama
    Abstract:

    The development of a fixed-wing nano air vehicle that fits inside a cube of 75 mm is described in this paper. A novel Aircraft Configuration that satisfies the static and dynamic stability and the mission performance requirements is developed. A performance index is formulated to identify a suitable airfoil as there does not exist a single airfoil that achieves the mission required specifications. Eppler-61 is identified as the suitable airfoil since the value of its performance index is maximum among other airfoils selected for the analysis. The static stability of the nano air vehicle is analyzed using the aerodynamic characteristics obtained from the wind tunnel tests. The outcomes of this analysis indicate that the vehicle is statically stable. The analysis also indicates significant aerodynamic cross-coupling between longitudinal and lateral aerodynamic coefficients. The dynamic stability analysis indicates that the nano air vehicle is dynamically stable. Furthermore, the dynamic stability of the vehicle is validated by flight test results.Published versio

Kandath Harikumar - One of the best experts on this subject based on the ideXlab platform.

  • 75-mm Wingspan Fixed-Wing Nano Air Vehicle With a Novel Aircraft Configuration
    IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 2018
    Co-Authors: Pushpangathan Jinraj, Kandath Harikumar, Bhat M Seetharama
    Abstract:

    The development of a fixed-wing nano air vehicle that fits inside a cube of 75 mm is described in this paper. A novel Aircraft Configuration that satisfies the static and dynamic stability and the mission performance requirements is developed. A performance index is formulated to identify a suitable airfoil as there does not exist a single airfoil that achieves the mission required specifications. Eppler-61 is identified as the suitable airfoil since the value of its performance index is maximum among other airfoils selected for the analysis. The static stability of the nano air vehicle is analyzed using the aerodynamic characteristics obtained from the wind tunnel tests. The outcomes of this analysis indicate that the vehicle is statically stable. The analysis also indicates significant aerodynamic cross-coupling between longitudinal and lateral aerodynamic coefficients. The dynamic stability analysis indicates that the nano air vehicle is dynamically stable. Furthermore, the dynamic stability of the vehicle is validated by flight test results

  • 75-mm wingspan fixed-wing nano air vehicle with a novel Aircraft Configuration
    'Institute of Electrical and Electronics Engineers (IEEE)', 2018
    Co-Authors: Pushpangathan Jinraj, Kandath Harikumar, Bhat M Seetharama
    Abstract:

    The development of a fixed-wing nano air vehicle that fits inside a cube of 75 mm is described in this paper. A novel Aircraft Configuration that satisfies the static and dynamic stability and the mission performance requirements is developed. A performance index is formulated to identify a suitable airfoil as there does not exist a single airfoil that achieves the mission required specifications. Eppler-61 is identified as the suitable airfoil since the value of its performance index is maximum among other airfoils selected for the analysis. The static stability of the nano air vehicle is analyzed using the aerodynamic characteristics obtained from the wind tunnel tests. The outcomes of this analysis indicate that the vehicle is statically stable. The analysis also indicates significant aerodynamic cross-coupling between longitudinal and lateral aerodynamic coefficients. The dynamic stability analysis indicates that the nano air vehicle is dynamically stable. Furthermore, the dynamic stability of the vehicle is validated by flight test results.Published versio