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Towards Certification by Analysis : = Large-Eddy Simulations of Commercial Aircraft Across the Flight Envelope.

紀錄類型:	書目-電子資源 : Monograph/item
正題名/作者:	Towards Certification by Analysis :/
其他題名:	Large-Eddy Simulations of Commercial Aircraft Across the Flight Envelope.
作者:	Goc, Konrad Andrzej.
面頁冊數:	1 online resource (149 pages)
附註:	Source: Dissertations Abstracts International, Volume: 84-12, Section: A.
Contained By:	Dissertations Abstracts International84-12A.
標題:	Aeronautics. -
電子資源:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=30462677click for full text (PQDT)
ISBN:	9798379651527

Towards Certification by Analysis : = Large-Eddy Simulations of Commercial Aircraft Across the Flight Envelope.
Goc, Konrad Andrzej.

Towards Certification by Analysis :Large-Eddy Simulations of Commercial Aircraft Across the Flight Envelope. - 1 online resource (149 pages)

Source: Dissertations Abstracts International, Volume: 84-12, Section: A.

Thesis (Ph.D.)--Stanford University, 2023.

Includes bibliographical references

This dissertation presents a summary of numerical simulations performed using several realistic aircraft models, both in landing and cruise configurations and describes the current state and predictive capabilities of high-fidelity Large Eddy Simulation (LES) applied to realistic commercial aircraft configurations. The objective of the selected cases is to demonstrate a level of capability and cost effectiveness of LES for the prediction aeronautical flows of engineering significance that will make LES a useful tool for routine use in the aerospace industry. One of the selected model problems is the Japanese Exploration Agency Standard Model (hereafter JSM). This configuration was selected due to the recent interest garnered by its featuring in the AIAA Third High-Lift Prediction Workshop where 35 participants submitted a total of 79 data sets of CFD results predicting the integrated forces and moments across the lift curve. Except for a few participants who used unsteady techniques (unsteady RANS [18], Lattice-Boltzman VLES [41], or delayed DES [12, 5]), most calculations presented in the workshop were steady RANS simulations deploying variants of the Spalart-Allmaras or SST models for the Reynolds stress closure [63]. A key takeaway from this workshop series has been that the accuracy of steady RANS techniques has plateaued, particularly near stall and in off-design conditions. Large variations from different solvers were also observed, even when the same models/gridding strategies were employed.The calculations described in this dissertation leverage an LES approach in which prohibitive cost requirements associated with wall-bounded turbulence at realistic Reynolds numbers [81, 15] necessitate the introduction of wall models to ameliorate the stringent grid requirements associated with wall-resolved LES. Equilibrium wall models in which the unsteady, convective, and pressure gradient terms appearing in the turbulent boundary layer equations are assumed to be in balance [38, 11] have been shown to work well in flows of interest [25, 28, 51, 8] and are used in this work. The combination of these physics-based modeling choices along with recent advances in computing hardware (such as GPU-based high-performance computing clusters) and low-dissipation numerical methods for LES [39] have made LES a powerful tool for use in informing design decisions in industry. Validation efforts such as the one presented in this dissertation are a key component towards building confidence in the predictive capability of this emerging computational fluid dynamics (CFD) paradigm.The studies presented herein which use the JSM configuration in general showed good prediction of the CL across the lift curve with the coefficient of lift at maximum lift, CL,max, being predicted to within 3 lift counts of the experimental value (i.e. within the tolerances required by the aerospace industry of ∆CL ≤ 0.03 at maximum lift[17]). The grid point requirements to achieve this level of accuracy are reduced compared to recent estimates (even for wall modeled LES), with the solutions showing systematic improvement upon grid refinement on grids numbering up to ≈ 150M cv. Investigations which included the wind tunnel facility were made in order to address one of the key deficiencies of the free air calculations: the incorrect prediction of the stall mechanism which in the free air cases was missing a large inboard separation.

Electronic reproduction.
Ann Arbor, Mich. :
ProQuest,
2023

Mode of access: World Wide Web

ISBN: 9798379651527Subjects--Topical Terms:

560293
Aeronautics.
Index Terms--Genre/Form:

542853
Electronic books.

Towards Certification by Analysis : = Large-Eddy Simulations of Commercial Aircraft Across the Flight Envelope.
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520 $a This dissertation presents a summary of numerical simulations performed using several realistic aircraft models, both in landing and cruise configurations and describes the current state and predictive capabilities of high-fidelity Large Eddy Simulation (LES) applied to realistic commercial aircraft configurations. The objective of the selected cases is to demonstrate a level of capability and cost effectiveness of LES for the prediction aeronautical flows of engineering significance that will make LES a useful tool for routine use in the aerospace industry. One of the selected model problems is the Japanese Exploration Agency Standard Model (hereafter JSM). This configuration was selected due to the recent interest garnered by its featuring in the AIAA Third High-Lift Prediction Workshop where 35 participants submitted a total of 79 data sets of CFD results predicting the integrated forces and moments across the lift curve. Except for a few participants who used unsteady techniques (unsteady RANS [18], Lattice-Boltzman VLES [41], or delayed DES [12, 5]), most calculations presented in the workshop were steady RANS simulations deploying variants of the Spalart-Allmaras or SST models for the Reynolds stress closure [63]. A key takeaway from this workshop series has been that the accuracy of steady RANS techniques has plateaued, particularly near stall and in off-design conditions. Large variations from different solvers were also observed, even when the same models/gridding strategies were employed.The calculations described in this dissertation leverage an LES approach in which prohibitive cost requirements associated with wall-bounded turbulence at realistic Reynolds numbers [81, 15] necessitate the introduction of wall models to ameliorate the stringent grid requirements associated with wall-resolved LES. Equilibrium wall models in which the unsteady, convective, and pressure gradient terms appearing in the turbulent boundary layer equations are assumed to be in balance [38, 11] have been shown to work well in flows of interest [25, 28, 51, 8] and are used in this work. The combination of these physics-based modeling choices along with recent advances in computing hardware (such as GPU-based high-performance computing clusters) and low-dissipation numerical methods for LES [39] have made LES a powerful tool for use in informing design decisions in industry. Validation efforts such as the one presented in this dissertation are a key component towards building confidence in the predictive capability of this emerging computational fluid dynamics (CFD) paradigm.The studies presented herein which use the JSM configuration in general showed good prediction of the CL across the lift curve with the coefficient of lift at maximum lift, CL,max, being predicted to within 3 lift counts of the experimental value (i.e. within the tolerances required by the aerospace industry of ∆CL ≤ 0.03 at maximum lift[17]). The grid point requirements to achieve this level of accuracy are reduced compared to recent estimates (even for wall modeled LES), with the solutions showing systematic improvement upon grid refinement on grids numbering up to ≈ 150M cv. Investigations which included the wind tunnel facility were made in order to address one of the key deficiencies of the free air calculations: the incorrect prediction of the stall mechanism which in the free air cases was missing a large inboard separation.
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