Sonic Boom Prediction Code Development and Sonic Boom Predictions via Open Source CFD Software

Abstract

In the present work a sonic boom prediction code which numerically solves the Augmented Burgers equation using the operator-splitting approach was developed. The developed code was tested using the near-field pressure data for the “NASA Concept 25D with Flow Through Nacelle (C25D)” and was validated by comparison with two well-known codes, namely sBoom and bBoom. A mid-solver approach, which utilizes the open source CFD software OpenFOAM® and a “Mach-cone aligned” structured mesh excluding the airplane geometry, was applied to extrapolate the nearfield pressure data to mid-field. The near-field effects were propagated to mid-field by solving the Euler equations. The Mach-cone aligned mesh used in the solutions were constructed using the open source mesh generation software Gmsh in an automated manner where the user specifies the radii of the inner and outer surfaces, mesh spacing along streamwise and circumferential directions and flow Mach number. The tests conducted using the near-field data obtained from an inviscid flow solution for the C25D geometry by the open source CFD software SU2 showed that this mid-solver approach used can successfully propagate near-field data to mid-field regions.

Keywords

• sonic boom prediction, augmented burgers equation, perceived loudness level, extrapolation to mid-field, openfoam®, su 2