An efficient method for incorporating computational fluid dynamics into sonic boom prediction

Page, Juliet A.; Plotkin, Kenneth J.

doi:10.2514/6.1991-3275

Cited by 54 publications

(24 citation statements)

References 1 publication

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“…The rear part of the signal, whatever the method, does not converge toward the undisturbed freestream state as it should. This is due to the numerical errors and instabilities of the system resolution as very high order expansion are considered as well as a high expansion order compared to the one usually found in the literature (see [9,12]). Furthermore, as the data extraction distance of r/L = 0.5 is small if compared to the commonly used one (r/L > 1), the matching must face stronger local gradients.…”

Section: Near-to Far-field Matchingmentioning

confidence: 99%

“…However, considering the current knowledge and computational means, using a nonviscous CFD solver is very convenient to predict the near-¦eld pressure disturbances ¤far¥ from the viscous boundary layer region. The nonlinear 3D aeroacoustic distortion due to the propagation through the mid-¦eld is assessed using the matching method proposed by Page and Plotkin [9]. Finally, the long distance acoustic propagation through standard strati¦ed atmosphere is carried out with a speci¦c acoustic code.…”

Section: Three-layer Approach Principlementioning

confidence: 99%

“…Even though attempts to perform CFD from the body to the ground with both evolutive schemes and equation formulations, as proposed by Kandil et al [7] or hybrid approaches more recently developed by Alauzet and Loseille performing calculations up to the far-¦eld before ray tracing propagation [8], the three-layer approach remains very competitive. Page and Plotkin proposed an e©cient three-layer approach [9] based on CFD computations for the near-¦eld, a near-to far-¦eld matching through multipole decomposition of the source of disturbances and an acoustic propagation through atmosphere. The matching approach exploits the work of George [10] on sonic boom minimization.…”

Section: Introductionmentioning

confidence: 99%

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Impact of multipole matching resolution on supersonic aircraft sonic boom assessment

Din

Pape

Minelli

et al. 2013

Progress in Flight Physics

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Sonic boom assessment methods through numerical analysis have been ever-evolving since the development of the fundamental theory. With the growing need for e©cient low-boom design tools and the increasing computational resources, original approaches using advanced numerical simulation techniques have been developed. Among the various existing methods, the three-layer resolution introduced in the 1990s is very convenient for low-boom aircraft design. It is based on near-¦eld computational §uid dynamics (CFD) calculation which is matched with the far-¦eld propagation code using a description of the source with multipoles before undergoing classical acoustic propagation through atmosphere. The present paper reviews the theory of the near-to far-¦eld matching as well as the di¨erent resolution approaches and their limits. The impact of the resolution method on the ground propagated signal is also presented.

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Section: Near-to Far-field Matchingmentioning

confidence: 99%

Section: Three-layer Approach Principlementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Impact of multipole matching resolution on supersonic aircraft sonic boom assessment

Din

Pape

Minelli

et al. 2013

Progress in Flight Physics

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“…The first method is to compute the surface pressures by using a CFD solver and then use numerical integration along the Mach plane cuts to generate equivalent area distributions. 12 The second method is to extract a CFD pressure off-body cylinder and apply multipole methods [13][14][15] to map the near-field pressures to their corresponding mid-field values so that the three dimensional cross-flow effects are taken care of before propagation to the ground. In the third approach, a CFD pressure solution that is obtained at several body lengths below the aircraft can be directly used for propagation to the ground.…”

Section: Sonic Boom Analysismentioning

confidence: 99%

Boom Minimization Framework for Supersonic Aircraft Using CFD Analysis

Ordaz

Rallabhandi

2010

48th AIAA Aerospace Sciences Meeting Including the New Horizons Forum and Aerospace Exposition

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A new framework is presented for shape optimization using analytical shape functions and high-fidelity computational fluid dynamics (CFD) via Cart3D. The focus of the paper is the system-level integration of several key enabling analysis tools and automation methods to perform shape optimization and reduce sonic boom footprint. A boom mitigation case study subject to performance, stability and geometrical requirements is presented to demonstrate a subset of the capabilities of the framework. Lastly, a design space exploration is carried out to assess the key parameters and constraints driving the design.

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“…The prediction of the intensity of the sonic boom has usually been computed by obtaining a near-to-mid-field (<10 body lengths below the aircraft) pressure distribution (Δp/p) and extending it to ground level using atmospheric propagation methods. 4 Using unstructured grids, where it can be difficult to control the distribution and orientation of the field grid beneath the model, pressure signatures in the mid-field typically are insufficiently predicted. Improved results have been obtained using an error-driven adjoint-based grid adaptation method 5,6 , but multiple runs using the flow and adjoint solvers can make the process cumbersome.…”

Section: Introductionmentioning

confidence: 99%

Grid Sourcing and Adaptation Study Using Unstructured Grids for Supersonic Boom Prediction

Carter

Deere

2008

26th AIAA Applied Aerodynamics Conference

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NASA created the Supersonics Project as part of the NASA Fundamental AeronauticsProgram to advance technology that will make a supersonic flight over land viable. Computational flow solvers have lacked the ability to accurately predict sonic boom from the near to far field. The focus of this investigation was to establish gridding and adaptation techniques to predict near-to-mid-field (<10 body lengths below the aircraft) boom signatures at supersonic speeds using the USM3D unstructured grid flow solver. The study began by examining sources along the body the aircraft, far field sourcing and far field boundaries. The study then examined several techniques for grid adaptation. During the course of the study, volume sourcing was introduced as a new way to source grids using the grid generation code VGRID. Two different methods of using the volume sources were examined. The first method, based on manual insertion of the numerous volume sources, made great improvements in the prediction capability of USM3D for boom signatures. The second method (SSGRID), which uses an a priori adaptation approach to stretch and shear the original unstructured grid to align the grid and pressure waves, showed similar results with a more automated approach. Due to SSGRID's results and ease of use, the rest of the study focused on developing a best practice using SSGRID. The best practice created by this study for boom predictions using the CFD code USM3D involved: 1) creating a small cylindrical outer boundary either 1 or 2 body lengths in diameter (depending on how far below the aircraft the boom prediction is required), 2) using a single volume source under the aircraft, and 3) using SSGRID to stretch and shear the grid to the desired length.

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An efficient method for incorporating computational fluid dynamics into sonic boom prediction

Cited by 54 publications

References 1 publication

Impact of multipole matching resolution on supersonic aircraft sonic boom assessment

Impact of multipole matching resolution on supersonic aircraft sonic boom assessment

Boom Minimization Framework for Supersonic Aircraft Using CFD Analysis

Grid Sourcing and Adaptation Study Using Unstructured Grids for Supersonic Boom Prediction

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