Document Type

Presentation

Journal/Book Title/Conference

AIAA Aviation 2019 Forum

Location

Dallas, Texas

Publication Date

6-14-2019

First Page

1

Last Page

19

Abstract

This paper presents a detailed comparison between the linear panel solver PANAIR A502 and the in-house Navier–Stokes solver UNS3D for a supersonic low-boom geometry. The high-fidelity flow solver was used to predict both the inviscid and laminar flow about the aircraft geometry. The JAXA wing body was selected as the supersonic low-boom geometry for this study. A comparison of the undertrack near-field pressure signatures showed good agreement between the three levels of model fidelity along the first 0.8L of the signature. Large oscillations in the PANAIR results were observed. The PANAIR discrepancies were traced back to violations of the underlying assumptions within PANAIR: (1) small perturbation velocities and (2) no regions of transonic flow. These violations were due to large changes in surface curvature resulting in a strong expansion wave. While investigating the PANAIR discrepancy, measures of the fundamental assumptions of the Prandtl-Glauert equation used by PANAIR were quantified and used to assess the applicability of PANAIR to a given problem. Further comparison of surface temperatures predicted between the inviscid and laminar solutions was made. It was found that the recovery temperatures predicted by the inviscid solution were 5% less than those predicted by the laminar solution in likely candidate regions for distributed adaptivity. A surface deformation was added to the forward portion of the geometry to asses the viability of a future optimization study in this region. In this study, it was found that the near-field and ground signatures predicted by PANAIR and the UNS3D solutions responded in similar manners to the deformation.

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