Potential Flow Analysis of Dynamic Ground EffectInterpretation of some flight test data suggests the presence of a 'dynamic ground effect'. The lift of an aircraft approaching the ground depends on the rate of descent and is lower than the aircraft steady state lift at a same height above the ground. Such a lift deficiency under dynamic conditions could have a serious impact on the overall aircraft layout. For example, the increased pitch angle needed to compensate for the temporary loss in lift would reduce the tail strike margin or require an increase in landing gear length. Under HSR2 an effort is under way to clarify the dynamic ground effect issue using a multi-pronged approach. A dynamic ground effect test has been run in the NASA Langley 14x22 ft wind tunnel. Northup-Grumman is conducting time accurate CFD (Computational Fluid Dynamics) Euler analyses on the National Aerodynamic Simulator facility. Boeing has been using linear potential flow methodology which are thought to provide much needed insight in, physics of this very complex problem. The present report summarizes the results of these potential flow studies.
Document ID
20000036442
Acquisition Source
Langley Research Center
Document Type
Conference Paper
Authors
W. M. Feifel (Boeing (United States) Chicago, Illinois, United States)
Date Acquired
September 8, 2013
Publication Date
December 1, 1999
Publication Information
Publication: 1998 NASA High-Speed Research Program Aerodynamic Performance Workshop: Volume II--High Lift
Publisher: National Aeronautics and Space Administration
Volume: 2
Issue Publication Date: December 1, 1999
URL: https://ntrs.nasa.gov/citations/20000036432
Subject Category
Aerodynamics
Meeting Information
Meeting: Aerodynamic Performance
Location: Los Angeles, CA
Country: US
Start Date: February 8, 1998
End Date: February 12, 1998
Sponsors: National Aeronautics and Space Administration