Investigation of VTOL Upwash Flows Formed by two Impinging Jets,
Abstract
This report presents results of an experimental investigation of the complex flows that occur under a VTOL vehicle operating near the ground. The effects of geometric and operating parameters on the upwash flow produced by ground impingement of two parallel subsonic jets have been modeled. This flow has been subdivided into separate, modular elements: jet impingement, wall jet behavior, stagnation line formation, and upwash flow field properties. Models have been developed and evaluated for each of these elements. These models can be used in numerical computation methods that have been developed to predict such ground effects as suckdown and upwash lift on VTOL aircraft. Parameters included in this investigation were jet velocity, distance from the ground, separation distance between jets, relative jet strength, impingement angle, and nozzle diameter. Properties of the upwash were determined by local flow measurements above the ground and by ground plane measurements of surface pressure and oil flow patterns.
Document Details
- Document Type
- Technical Report
- Publication Date
- Nov 01, 1977
- Accession Number
- ADA047805
Entities
People
- Richard C. Jenkins
- William G. Hill Jr.
Organizations
- Grumman