Accession Number : ADA299698
Title : Thrust Vector Control of Rectangular Jets Using Counterflow.
Descriptive Note : Final technical rept. 1 Jan 94-30 Jun 95,
Corporate Author : MINNESOTA UNIV MINNEAPOLIS OFFICE OF RESEARCH AND TECHNOLOGY TRANSFER ADMINIS TRATION
Personal Author(s) : Veer, Michael R. Van der ; Strykowski, Paul J.
PDF Url : ADA299698
Report Date : 31 AUG 1995
Pagination or Media Count : 141
Abstract : Fluidic vectoring of a subsonic jet was examined using a curved countercurrent mixing layer. A rectangular jet having a 4:1 aspect ratio was studied at Mach numbers up to 0.5 at a stagnation temperature of 300 K. Several different curved control surfaces called "collars" were placed downstream of the nozzle exit over which the pressure forces could act to produce jet thrust vectoring. Results showed that by applying counterfiow over the collar surface, the entrainment characteristics of the jet shear layer could be altered, thereby establishing the cross stream pressure gradient necessary to achieve continuous thrust vectoring up to 220. Under certain conditions, however, continuous thrust vector control was lost, causing jet attachment to the collar. This condition resulted in a strong hysteresis loop which demanded that the suction be reduced considerably before the jet detached from the collar surface. Since such bistability was undesirable for applications requiring continuous control, the phenomenon was studied in detail. Optimization of the collar geometry was shown to delay jet attachment, creating a larger regime of smooth and continuous vectoring.
Descriptors : *SUBSONIC FLOW, *THRUST VECTOR CONTROL SYSTEMS, *CROSS FLOW, PRESSURE GRADIENTS, OPTIMIZATION, TURBULENCE, FLOW VISUALIZATION, MASS FLOW, SUBSONIC CHARACTERISTICS, MACH NUMBER, TWO DIMENSIONAL FLOW, INVISCID FLOW, PRESSURE DISTRIBUTION, HYSTERESIS, ENTRAINMENT, MOMENTUM, STAGNATION TEMPERATURE, NOZZLE GAS FLOW, SHEAR FLOW, BOUNDARY LAYER FLOW, AXISYMMETRIC FLOW, EXHAUST GASES, JET MIXING FLOW, COANDA EFFECT, CONVERGENT DIVERGENT NOZZLES.
Subject Categories : Fluid Mechanics
Distribution Statement : APPROVED FOR PUBLIC RELEASE