Summary of the 2008 NASA Fundamental Aeronautics Program Sonic Boom Prediction Workshop

Abstract

The Supersonics Project of the NASA Fundamental Aeronautics Program organized an internal sonic boom workshop to evaluate near-and mid-field sonic boom prediction capability at the Fundamental Aeronautics Annual Meeting in Atlanta, Georgia on October 8, 2008. Workshop participants computed sonic boom signatures for three non-lifting bodies and two lifting configurations. A cone-cylinder, parabolic, and quartic bodies of revolution comprised the non-lifting cases. The lifting configurations were a simple 69-degree delta wing body and a complete low-boom transport configuration designed during the High Speed Research Project in the 1990s with wing, body, tail, nacelle, and boundary layer diverter components. The AIRPLANE, Cart3D, FUN3D, and USM3D flow solvers were employed with the ANET signature propagation tool, output-based adaptation, and a priori adaptation based on freestream Mach number and angle of attack. Results were presented orally at the workshop. This article documents the workshop, results, and provides context on previously available and recently developed methods.

Nearfield Summary and Statistical Analysis of the Second AIAA Sonic Boom Prediction Workshop

“…The statistical products and grid convergence studies continue the process of quantifying the uncertainty of nearfield CFD employed by the international participants. SBPW2 benefits from the lessons learned at the 2008 NASA Sonic Boom Prediction Workshop [4] and SBPW1 [1,5]. Experience from AIAA Drag [6,7], High Lift [8], and Shock Boundary Layer Interaction [9] Prediction Workshops also contributed to the success of the current workshop.…”

“…NASA 2008 workshop summary [4] observed, "The two adjoint-based adaptation techniques produced identical signatures, except in the extrema, where limiter behavior is important or where the boundary conditions or geometry differed." Impact of limiters on nearfield pressure signatures was also studied by Park [72].…”

Cart3D Simulations for the Second AIAA Sonic Boom Prediction Workshop

“…As observed with many other CFD approaches [1,19], early investigations showed that Cartesian meshes can be highly effective at computing off-body signatures, provided that the mesh is nearly aligned with the Mach-angle μ of the freestream flow [8]. Good Mach alignment reduces dissipation and permits the mesh to be stretched in the propagation direction, further reducing the cell count [8].…”

“…2008: NASA Fundamental Aeronautics Program Sonic Boom Prediction Workshop [1] 2014: AIAA Sonic Boom Prediction Workshop 1 (SBPW1) [2] 2017: AIAA Sonic Boom Prediction Workshop 2 (SBPW2) [3] The purpose of these workshops is both to document the evolving state-of-the-art in boom prediction methods and to provide focus for future investment and research efforts.…”

Adjoint-Based Mesh Adaptation for the Sonic Boom Signature Loudness

“…20,21 The success of this method for Euler CFD was demonstrated at the 2008 NASA Fundamental Aeronautics Program Sonic Boom Prediction Workshop, where two independent output-based adaptation schemes produced equivalent (grid converged) near-field signatures. 22 Despite earlier success using near-field target pressure deviation for mesh adaptation (dpp adaptation), this is only a heuristic when the analysis and control of the ASEL ground noise measure is the objective. Using the adjoint-based methodology for ASEL eliminates the assumption of the quadratic pressure integral and its emphasis on the largest pressure deviations from ambient pressures and improves the accuracy of ASEL by appropriately refining the mesh using coupled, multi-disciplinary sonic boom analysis.…”