Direct calculation of aerodynamic force derivatives - A sensitivity-equation approach

Godfrey, Andrew G.; Cliff, Eugene M.

doi:10.2514/6.1998-393

Cited by 36 publications

(19 citation statements)

References 3 publications

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“…Why not use sensitivity analysis to solve the exact equations that govern the stability and control coefficients? 40,90 Aerodynamic Design Methods There has been significant progress this decade in gradient-based aerodynamic design methods, with the most efficient methods utilizing hand-coded sensitivities and adjoints (although no one has yet been masochistic enough to produce a hand-coded adjoint that includes the turbulence model). The next challenge in this line is to adapt these methods to multidisciplinary problems, e.g., to aerodynamicsstructures problems.…”

Section: Figure 14mentioning

confidence: 99%

Multidisciplinary design optimization techniques - Implications and opportunities for fluid dynamics research

Zang

Green

1999

30th Fluid Dynamics Conference

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A challenge for the fluid dynamics community is to adapt to and exploit the trend towards greater multidisciplinary focus in research and technology. The past decade has witnessed substantial growth in the research field of Multidisciplinary Design Optimization (MDO). MDO is a methodology for the design of complex engineering systems and subsystems that coherently exploits the synergism of mutually interacting phenomena. As evidenced by the papers, which appear in the biannual AIAA/USAF/NASA/ISSMO Symposia on Multidisciplinary Analysis and Optimization, the MDO technical community focuses on vehicle and system design issues. This paper provides an overview of the MDO technology field from a fluid dynamics perspective, giving emphasis to suggestions of specific applications of recent MDO technologies that can enhance fluid dynamics research itself across the spectrum, from basic flow physics to full configuration aerodynamics.

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Section: Figure 14mentioning

confidence: 99%

Multidisciplinary design optimization techniques - Implications and opportunities for fluid dynamics research

Zang

Green

1999

30th Fluid Dynamics Conference

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“…Charlton [9] conducted simple α and β sweeps to get the force and moment information required for falling-leaf predictions for tailless aircraft. Godfrey and Cliff [10] explored the use of analytic sensitivity methods-in particular, the direct method-for the computation of static stability derivatives. Park et al [11] applied ADIFOR [12], an automatic differentiation (AD) tool, to a three-dimensional viscous flow solver to compute the static derivatives of various configurations.…”

Section: Introductionmentioning

confidence: 99%

Computing Stability Derivatives and Their Gradients for Aerodynamic Shape Optimization

Mader

Martins

2014

AIAA Journal

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“…The sensitivity equations are then discretized and solved numerically to obtained the desired sensitivities. Aerodynamics applications of the CSE method may be found in Godfrey and Cliff [28,29], Borggaard and Burns [25], Limache [30] and Turgeon et al [31]. Application to heat conduction is reported by Blackwell et al [32].…”

Section: Introductionmentioning

confidence: 99%

Finite element and sensitivity analysis of thermally induced flow instabilities

Giguère

Ilinca

Pelletier

2010

Numerical Methods in Fluids

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This paper presents a finite element algorithm for the simulation of thermo‐hydrodynamic instabilities causing manufacturing defects in injection molding of plastic and metal powder. Mold‐filling parameters determine the flow pattern during filling, which in turn influences the quality of the final part. Insufficiently, well‐controlled operating conditions may generate inhomogeneities, empty spaces or unusable parts. An understanding of the flow behavior will enable manufacturers to reduce or even eliminate defects and improve their competitiveness. This work presents a rigorous study using numerical simulation and sensitivity analysis. The problem is modeled by the Navier–Stokes equations, the energy equation and a generalized Newtonian viscosity model. The solution algorithm is applied to a simple flow in a symmetrical gate geometry. This problem exhibits both symmetrical and non‐symmetrical solutions depending on the values taken by flow parameters. Under particular combinations of operating conditions, the flow was stable and symmetric, while some other combinations leading to large thermally induced viscosity gradients produce unstable and asymmetric flow. Based on the numerical results, a stability chart of the flow was established, identifying the boundaries between regions of stable and unstable flow in terms of the Graetz number (ratio of thermal conduction time to the convection time scale) and B, a dimensionless ratio indicating the sensitivity of viscosity to temperature changes. Sensitivities with respect to flow parameters are then computed using the continuous sensitivity equations method. We demonstrate that sensitivities are able to detect the transition between the stable and unstable flow regimes and correctly indicate how parameters should change in order to increase the stability of the flow. Copyright © 2009 John Wiley & Sons, Ltd.

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Direct calculation of aerodynamic force derivatives - A sensitivity-equation approach

Cited by 36 publications

References 3 publications

Multidisciplinary design optimization techniques - Implications and opportunities for fluid dynamics research

Multidisciplinary design optimization techniques - Implications and opportunities for fluid dynamics research

Computing Stability Derivatives and Their Gradients for Aerodynamic Shape Optimization

Finite element and sensitivity analysis of thermally induced flow instabilities

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