Accession Number:

AD1076362

Title:

Tracking Shock Movement on the Surface of an Oscillating, Straked Semispan Delta Wing

Descriptive Note:

Technical Report,01 Aug 2017,21 Mar 2019

Corporate Author:

AIR FORCE INSTITUTE OF TECHNOLOGY WRIGHT-PATTERSON AFB OH WRIGHT-PATTERSON AFB United States

Personal Author(s):

Report Date:

2019-03-21

Pagination or Media Count:

122.0

Abstract:

Limit cycle oscillations LCO, an aeromechnical instability similar to flutter, have affected high performance aircraft, like the F-16 and F-18, for years. To better understand the nature of LCO and why high-performance aircraft were typically afflicted, a series of wind tunnel experiments were conducted. The experiments were designed to investigate the flow field around a straked, semispan delta wing and monitor the changes as the semispan was pitched in an oscillatory fashion. By understanding the flow field around an oscillating wing, the fluid force that causes the motion could be discerned. The wind tunnel experiments and recent computational methods have focused on tracking shock movement along the top surface of the semispan to confirm the presence of shock-induced trailing edge separation, one possible LCO driver. For the current effort, a computational model was developed to compare to the results of the wind tunnel tests and discern more information about the flow features around a straked, delta wing. The computational model was constructed using the Cartesian overset capabilities of the fixed wing fluid dynamics solver Kestrel. Overall, the numerical results showed good qualitative agreement with the wind tunnel tests. Shock-induced trailing edge separation SITES was observed during a large number of the simulations, proving its prevalence at flow conditions pertinent to LCO motion. The high angle of attack simulations demonstrated good agreement with the experimental data, especially the integrated values.

Subject Categories:

  • Fluid Mechanics
  • Attack and Fighter Aircraft

Distribution Statement:

APPROVED FOR PUBLIC RELEASE