Fountain-Jet Turbulence.

reportActive / Technical Report | Accession Number: ADA098098 | Open PDF

Abstract:

A series of experiments was conducted on a model to investigate the characteristics of fountain jets that develop beneath hovering VSTOL aircraft. The results confirm the results of previous studies in that normally developing fountains possess abnormally high turbulence levels that can be reduced by the presence of trip devices placed along the fountain stagnation line. The present work shows that fountain turbulence is highly anisotropic with the intensity of the streamwise component an order of magnitude greater than the cross component. Further, the anamoly appears to occur only in fountains produced by jets of air that strike normal to the ground surface jets that strike at angles other than the perpendicular do not appear to generate highly turbulent fountains. Author

Author(s):
Foley, William H. ; Finlay, Dennis B.
Author Organization(s):
GENERAL DYNAMICS CORP FORT WORTH TX FORT WORTH DIV
Descriptive Note:
Final rept. 1 Oct 79-30 Sep 80,
Supplementary Note:
DOI: 10.21236/ADA098098
Pagination:
0021

Security Markings

DOCUMENT & CONTEXTUAL SUMMARY

Distribution:
Approved For Public Release

RECORD

Collection: TR
Identifying Numbers
Report Number(s):
AFOSR-TR-81-0286
Contract/Grant Number(s):
F49620-80-C-0003
Task Number(s):
A1
Project Number(s):
2307
Monitor Series:
TR-81-0286
 Subject Terms
Joint Capability Areas:
JCA_6.3.3_Spectrum Management; JCA_6_Net Centric; JCA_1.2.7_Experimentation; JCA_6.3_Net Management
Communities of Interest:
Air Platforms
Descriptor(s):
*TURBULENT FLOW, *JET FLOW, *HOVERING, VELOCITY, FLOW FIELDS, VERTICAL TAKEOFF AIRCRAFT, BUOYANCY, TRIP WIRES, BOUNDARY LAYER FLOW, STAGNATION, SHORT TAKEOFF AIRCRAFT, RIGHT ANGLES
Field(s)/Group(s):
Fluid Mechanics
Keyword(s):
*Fountain jet turbulence, Air jets, Fountain buoyancy, Suckdown, WUAFOSR2307A1, PE61102F
Report Date:
1980 Sep 01