Program determines flow field about jets with velocity stratification exhausting into crossflow. Jets with three different types of exit-velocity stratification have been considered: (a) jets with relatively high-velocity core, (b) jets with relatively low-velocity core, and (c) jets originating from vaned nozzle

Ziegler, H.

English

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NASA TECH BRIEF 
Langley Research Center .
November 1974	 B74-10207 
NASA Tech Briefs announce new technology derived from the U.S. space program. They are issued to encourage 
commercial application. Tech Briefs are available on a subscription basis from the National Technical Information 
Service, Springfield, Virginia 22151. Requests for individual copies or questions relating to the Tech Brief program may 
be directed 10 the Technology Utilization Office, NASA, Code KT, Washington, D.C. 20546. 
Investigation of Exit-Velocity Stratification Effects on

Jets in a Crossflow (STRJET) 
.
The problem: 
A fundamental problem in the development of 
methods for predicting aerodynamic characteristics of 
lift-jet, vector-thrust, and lift-fan V/STOL (Vertical! 
Short Takeoff and Landing) aircraft is that of formula-
ting a mathematical model to estimate the effects of the 
propulsion system efflux interaction with a crossflow. 
The solution: 
A considerable amount of research activity, both 
experimental and analytical, has been devoted to the 
development of an understanding of this flow problem 
and also to a computer program to calculate the 
resulting interference flow fields. 
How it's done: 
A program has been developed for determining the 
flow field about jets with velocity stratification exhaust-
ing into a crossflow. Jets with three different types of 
exit-velocity stratification have been considered, namely: 
(a) jets with a relatively high-velocity core, (b) jets with 
a relatively low-velocity core, and (c) jets originating 
from a vaned nozzle. 
The procedure developed for a jet originating from a 
high-velocity core nozzle is to construct an equivalent 
nozzle having the same mass flow and thrust but having 
a uniform exit-velocity profile. Calculations of the jet 
centerline and induced surface static pressures are 
shown to be in good agreement with test data for a high-
velocity core nozzle. The equivalent ideal nozzle is also 
shown to be a good representation for jets with a 
relatively low-velocity core and for jets originating from 
a vaned nozzle, in evaluating jet-induced flow fields.
For the singular case of a low-velocity core nozzle, 
namely a nozzle with a dead air core, and for the vaned 
nozzle, an alternative procedure has been developed. The 
internal mixing which takes place in the jet core has 
been properly accounted for in the equations of motion 
governing the jet development. The calculations of jet 
centerlines and the induced surface static pressures 
showed good agreement with the test data for these 
nozzles. 
A method for treating two-jet configurations has 
been extended to include mutual interference effects 
between the two jets, in addition to the jet blockage 
effects already considered. Comparisons have been made 
between the calculations and the test data for a number 
of jet configurations. 
Notes: 
1. This program was written in FORTRAN IV for the 
CDC 6000-series computers. 
2. Inquiries concerning this program should be directed 
to:
COSMIC 
112 Barrow Hall 
University of Georgia 
Athens, Georgia 30601 
Reference: LAR-1 1581
Source: H. Ziegler of

Northrop Corp.

under contract to

Langley Research Center 
(LAR-1 1581) 
Category 09,03,06 
This document was prepared under the sponsorship of the National
	
Government assumes any liability resulting from the use of the 
Aeronautics and Space Administration. Neither the United States	 information contained in this document, or warrants that such use 
Government nor any person acting on behalf of the United States
	
will be free from privately owned rights.
https://ntrs.nasa.gov/search.jsp?R=19740000207 2020-03-17T13:51:04+00:00Z


Investigation of exit-velocity stratification effects on jets in a crossflow (STRJET)

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