A modified adjoint-based grid adaptation and error correction method for unstructured grid

Cui, Pengcheng; Li, Bin; Tang, Jing; Chen, Jiangtao; Deng, Youwen

doi:10.1142/s0217984918400201

Cited by 4 publications

(3 citation statements)

References 6 publications

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“…The numerical computations in this paper are implemented by the China Aerodynamics Research and Development Center, where there is an inhouse flow solver NNW-FlowStar [13][14], which has developed feature-based grid adaptation and adjoint-based grid adaptation. FlowStar is an unstructured finite volume CFD solver, which attended several drag and hi-lift workshops, the results show that FlowStar behaved excellently in predicting aerodynamic characteristics [15][16].…”

Section: Methodsmentioning

confidence: 99%

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The comparison of adjoint-based grid adaptation and feature-based grid adaptation method

Cui

Zheng

et al. 2022

J. Phys.: Conf. Ser.

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Grid adaption is a popular method to enhance the resolution of flow field and the precision of numerical simulation, which automatically optimizes the grid distribution instead of manual complicated work. There exist usually two grid adaptation methods, the feature based grid adaption and adjoint based grid adaption, the former focuses on shocks, vortexes and other features of flow field, and the latter focuses on lift, drag and other aerodynamic characteristics. The comparison of adjoint based grid adaption and feature based grid adaption method is investigated in this paper. Numerical simulations show that both feature adaption and adjoint adaption could improve the resolution of flow field and the precision of numerical simulation such as lift and drag. As for the flow features, the feature adaptation could capture the obvious shock waves and vortexes in the flow field, the adjoint adaptation, however, only captures the flow features that are contributory to the accuracy of aerodynamic characteristics. As for the aerodynamic characteristics, some shock waves and vortexes have little influences to the forces, so the feature adaptation is not efficient as adjoint adaptation, which could greatly improve the accuracy of aerodynamic characteristics.

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Section: Methodsmentioning

confidence: 99%

“…The discretization error of target function can be calculated by adjoint equations. The estimation of objective function can be expressed as: The adaption parameter provides the guidance of arid adaptation [13]:…”

Section: Adjoint Based Grid Adaptationmentioning

confidence: 99%

The comparison of adjoint-based grid adaptation and feature-based grid adaptation method

Cui

Zheng

et al. 2022

J. Phys.: Conf. Ser.

Self Cite

View full text Add to dashboard Cite

show abstract

“…The numerical simulations in this paper were conducted by the China Aerodynamics Research & Development Center (CARDC) NNW-Flowstar software [12][13][14], which is an unstructured finite volume cell-center CFD solver and has participated in the 5th and 6th CFD drag prediction workshop. Roe scheme is used for inviscid flux computations [15].…”

Section: Flow Solvermentioning

confidence: 99%

Flow Characteristic Study of High-speed Cavity Based on Detached-eddy Simulations

Zheng

Zhang

et al. 2022

J. Phys.: Conf. Ser.

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The cavity is widely used in the advanced flight vehicle. However, there are also some new aerodynamic characteristic when cavity is exposed in high-speed flow. The flow characteristic of high-speed cavity is studied in this paper based on detached-eddy simulation method. The M219 cavity benchmark under transonic flow is used as the validation case for numerical methods and grid strategy. Comparison of predicted sound pressure levels and spectra against the wind tunnel experiment has proved that the numerical methods capture the major oscillation dynamics inside the cavity. The aerodynamic characteristic of cavity with a store is investigated in this paper, there are three vortexes in the cavity and the main vortex in the middle rotates around the store. The shear layer breaks earlier compared with clean cavity due to the turbulent flow around the store. However, the small store has little influence to the sound pressure level of cavity.

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Improved Delayed Detached-Eddy Investigations on the Flow Control of the Leading-Edge Flat Spoiler of the Cavity in the Low-Aspect-Ratio Aircraft

et al. 2022

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The internal weapon bay is widely used in modern aircraft; however, because the unsteady flows of the cavity would cause dangerous store separation and intense aerodynamic noise, the leading-edge spoiler is an easy and efficient passive flow-control method. The flow control of the leading-edge flat spoiler before the cavity of a low-aspect-ratio flying-wing aircraft is investigated based on numerical simulation. Numerical results show that the leading-edge flat spoiler completely changes the cavity flow; it obviously lifts up the shear layer and reduces the pressure inside the cavity. For the store separation from the weapon bay, the leading-edge flat spoiler is a very good passive flow-control method that curbs the nose-up trend of the store and produces a safe and stable store separation. Besides, the leading-edge spoiler reduces the noise in the rear of the cavity (max 8.2 dB), but increases the noise in the middle of the cavity (max 11.3 dB). In addition, the leading-edge spoiler brings in a large drag increase to the aircraft (39.41% when the height of spoiler is 0.2 m), which would affect the operational stability of the aircraft. The results of this paper could provide a reference for the flow control of weapon bays and the design of aircraft.

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A modified adjoint-based grid adaptation and error correction method for unstructured grid

Cited by 4 publications

References 6 publications

The comparison of adjoint-based grid adaptation and feature-based grid adaptation method

The comparison of adjoint-based grid adaptation and feature-based grid adaptation method

Flow Characteristic Study of High-speed Cavity Based on Detached-eddy Simulations

Improved Delayed Detached-Eddy Investigations on the Flow Control of the Leading-Edge Flat Spoiler of the Cavity in the Low-Aspect-Ratio Aircraft

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