The Use of Pressure Constructs in Aerodynamics May Lead to Misinformation

From biology, to genetics, and paleontology, these fields share the DNA as a common and time-proven tool. In science, pressure may be such a tool, shared by thermodynamics, material science, and astrophysics, but not by aerodynamics. Pressure is a shorthand for a force acting perpendicular to a surface. When this surface is reduced to zero, so should the pressure. The wing area of an aircraft acts as a reference area to calculate its parasite drag coefficient. In this scenario, the parasite drag acts as a force over the wing area. If the wing area is reduced to zero, its parasite drag does not, as the fuselage is still generating parasite drag. The ratio of the parasite drag and wing area is an example of a pressure construct that uses a physically irrelevant reference area and has no absolute zero. Pressure constructs, more frequently used than pressures in aerodynamics, are a math-based parameter that preserve dimensional propriety according to the Buckingham Pi theorem but lacks a physical meaning and causes geometry bias, which may lead to misinformation. This article discusses the shortcomings of using pressure constructs in the legacy lift and drag equations, and the benefits of using actual pressures within the recently introduced aerodynamic equation of state of engineered and biological flyers.

• Record URL:
  • https://doi.org/10.4271/01-17-03-0020
• Availability:
  • Find a library where document is available. Order URL: http://worldcat.org/issn/19463855
• Supplemental Notes:
  • Abstract reprinted with permission of SAE International.
• Authors:
  • Burgers, Phillip
• Publication Date: 2025-1-6

Language

• English

Media Info

• Media Type: Web
• Features: References;
• Pagination: pp 325-337
• Serial:
  • SAE International Journal of Aerospace
  • Volume: 17
  • Issue Number: 3
  • Publisher: SAE International
  • ISSN: 1946-3855
  • EISSN: 1946-3901
  • Serial URL: https://www.sae.org/publications/collections/content/e-journal-01/

Subject/Index Terms

• TRT Terms: Aerodynamics; Aircraft wings; Drag; Fabrication; Flight dynamics; Fuselages; Pressure; Properties of materials
• Subject Areas: Aviation; Vehicles and Equipment;

Filing Info

• Accession Number: 01942890
• Record Type: Publication
• Source Agency: SAE International
• Report/Paper Numbers: 01-17-03-0020
• Files: TRIS, SAE
• Created Date: Jan 21 2025 10:22AM