Improved supersonic performance design for the F-16 inlet modified for the J-79 engine

Hunter, L.; Cawthon, J.

doi:10.2514/6.1984-1272

Cited by 6 publications

(2 citation statements)

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“…6. The F-16/79 inlet was designed for higher Mach number performance, 13 with an inlet ramp extended approximately 20 in. for more efficient compression and a bleed system to stabilize the shock.…”

Section: Configuration 2 (Two-dimensional F-16/79 Inlet Mach 20 a mentioning

confidence: 99%

Supersonic inlet study using the Navier-Stokes equations

Hunter

Tripp

Howlett

1986

Journal of Propulsion and Power

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The three-dimensional, unsteady, compressible Navier-Stokes equations were numerically solved for the flowfield about three external-compression inlet configurations. Configuration 1 was a generic Mach 2.2 variable-geometry, two-ramp inlet with a bleed slot. Configuration 2 was an F-16/79 inlet at Mach 2.0 with porous-ramp and slot bleed. For these configurations, two different approaches were used to model the bleed. Configurations 1 and 2 were modeled by using three lateral planes in the three-dimensional code with symmetry around the center plane, which provides an equivalent two-dimensional solution. Configuration 3 was an axisymmetric spike inlet at Mach 2.2 at 0 deg angle of attack. A full three-dimensional solution was obtained for this configuration. For configurations 2 and 3, the computed surface pressures are in good agreement with the experimental data for cases with and without bleed. The computed pressure recovery at the throat for the threedimensional spike inlet at A Q /A f = 0.84 was 2% higher than the compressor-face data. In all the configurations, a computational flow plug was used for the duct outflow boundary. This flow plug eliminates the need to specify a back pressure, particularly at angles of incidence, where the back pressure varies circumferentially. Due to limited computer resources, the analysis was limited to the shock system plus 25-45% of the subsonic diffuser length. Numerical results are given in terms of Mach number and static pressure plots and are compared with experimental data. Nomenclaturespecific heat at constant volume e = specific internal energy, C V T E = total internal energy F,G,H = vector flux M =Mach number P,P T = static and total pressure q =heat flux R = gas constant s = entropy T -static temperature u, v y w -Cartesian velocity components U = vector of dependent variables [p,p«,pt>,pw,p£] x,y,z = Cartesian coordinates a.= angle of attack 7 = ratio of specific heats H,fjL t = molecular and turbulent viscosity coefficients, respectively Ht->v>t = inner and outer turbulent viscosity coefficients, respectively £,r;,f = transformed body fitted coordinates p = density a,r = viscous stress tensors 0 = circumferential position

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Section: Configuration 2 (Two-dimensional F-16/79 Inlet Mach 20 a mentioning

confidence: 99%

Supersonic inlet study using the Navier-Stokes equations

Hunter

Tripp

Howlett

1986

Journal of Propulsion and Power

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“…The resulting spillage drag distributions are shown in Figure 33 compared to the data of Hunter and Cawthon (1984).…”

Section: Test Case -F-16 Inlet Spillage Dragmentioning

confidence: 99%

Inlet drag prediction for aircraft conceptual design

Malan

Brown

1994

Journal of Aircraft

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Mechanical Engineering (ABSTRACT)A research effort aimed at enhancing ACSYNT, a computer program for aircraft conceptual design, has necessitated the development of methods for predicting inlet drag.Originally, the drag of only one inlet type, the variable-geometry conical inlet, could be calculated within ACSYNT. This prompted the present research which resulted in the creation of a modular suite of subroutines that extend the capability of ACSYNT. Using this new source code, ACSYNT can now predict the drag of subsonic and supersonic pitot inlets, fixed-and variable-geometry conical inlets, and two-dimensional supersonic inlets.Even though the requirement of computational efficiency has necessitated that many simplifications be made in the analysis, the drag calculations have a sound physical basis. The semi-empirical methods have been extracted from a number of sources based on an extensive literature survey, and these have been enhanced to encompass the full range of inlet operating conditions. The effectiveness of the methods has been demonstrated by comparing some results of the predictions to published data. AcknowledgementsI would like to thank the fallowing faculty members who served on my committee:Professor Eugene F. Brown, my advisor, for his willing assistance and guidance during the course of this work; Professor Arvid Myklebust, for his able management of the ACSYNT project; Professor J. Robert Mahan, for getting me involved with the project.Grateful acknowledgement is given to the Powered Lift Investigations Branch, NASA Ames Research Center, for providing the financial support for this work.Thanks also to and the rest of the ACSYNT team. The meetings wouldn't have been the same without them! Finally, a special thanks to my wife who made great sacrifices so that I could come to Virginia Tech. Without her love and support, we just wouldn't be here.. .. .. Tables Table 1. NACA I-Series Cowl Coordinates (from Seddon and Goldsmith ( 1985), Aircraft conceptual design is the process whereby the size and general configuration of an aircraft are selected to meet a specific mission profile. This process involves the choice of a candidate aircraft layout, and an initial guess must be made as to its overall size. Acknowledgements IllThe aircraft is then synthesized by a series of design relations which describe important aspects of the design such as the aerodynamic performance, component weights and the propulsion system performance. This synthesis enables the aircraft weight to be calculated, and hence the initial aircraft layout can be revised accordingly. The procedure needs to be repeated until the design converges satisfactorily. This iterative design process is best performed by computer, thus enabling the design turn-around time to be minimized without foregoing the use of relatively complex design relations.ACSYNT is one such computer program for aircraft synthesis and conceptual design.It is distinguished by the incorporation of numerical optimization techniques to allow specific characteri...

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