Comparison between experimental and numerical results for a researchhypersonic aircraft

Richardson, Pamela F.; Parlette, Edward B.; Morrison, Joseph H.; Switzer, George; Dilley, Arthur D.

doi:10.2514/3.25272

Cited by 9 publications

(2 citation statements)

References 2 publications

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“…Previous studies have shown that y + values on the order of 1.0 will yield an accurate solution. 9 A diagram of both the waverider and flat-top model grids is shown in figure 4.…”

Section: Computational Studymentioning

confidence: 99%

Interpretation of waverider performance data using computational fluid dynamics

Cockrell

1994

Journal of Aircraft

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A computational study was conducted to better understand experimental results obtained from wind tunnel tests of a Mach 4 waverider model and a comparative reference configuration. The experimental results showed that the performance of the reference configuration was slightly better than that of the waverider model. These results contradict waverider design theory, which suggests that a waverider optimized for maximum lift-to-drag should provide better performance than any other non-waverider configuration at a given design point, especially at hypersonic speeds. The computational results showed that the predicted surface pressure values and the integrated lift and drag coefficients from the pressure distributions were much lower for the reference model than for the flat-top model, due to the reference model bottom surface having a slight expansion. The lift-to-drag ratios for the flat-top model were higher due to a relatively low drag for the same amount of lift. These results indicate that the performance advantage of the reference model was due to the shape of the bottom surface and not due to the flat top surface. The results also showed that the reference model exhibited the same shock attachment characteristics as the waverider because the planform shapes were identical. CFD predictions show that the planform shape gives the waverider an advantage in performance over conventional hypersonic vehicles and that altering the bottom surface of a waverider does not cause significant performance degradation.

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“…Previous studies have shown that y + values on the order of 1.0 will yield an accurate solution. 9 A diagram of both the waverider and flat-top model grids is shown in figure 4.…”

Section: Computational Studymentioning

confidence: 99%

Interpretation of waverider performance data using computational fluid dynamics

Cockrell

1994

Journal of Aircraft

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“…The downstream boundary was ascribed a second-order extrapolation boundary condition, while the upper and lower center-planes of the grid had an x-z symmetry boundary condition imposed. The grids were clustered near solid surfaces such that the average value of the inner law variable 9 at the first computational cell center away from the body was about three, with some localized regions that were as high as twelve (on the wing leading edge). Marching plane residuals were reduced five orders of magnitude for the first three planes of the external and internal flows, providing a good establishment of the solution features.…”

Section: Cfd Solution Issuesmentioning

confidence: 99%

CFD code calibration and inlet-fairing effects on a 3D hypersonic powered-simulation model

Lawrence

Kenneth²

1993

23rd Fluid Dynamics, Plasmadynamics, and Lasers Conference

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A three-dimensional (3D) computational study has been performed addressing issues related to the wind tunnel testing of a hypersonic powered-simulation model. The study consisted of three objectives. The first objective was to calibrate a state-of-the-art computational fluid dynamics (CFD) code in its ability to predict hypersonic powered-simulation flows by comparing CFD solutions with experimental surface pressure data. Aftbody lower surface pressures were well predicted, but lower surface wing pressures were less accurately predicted. The second objective was to determine the 3D effects on the aftbody created by fairing over the inlet; this was accomplished by comparing the CFD solutions of two closed-inlet powered configurations with a flowing-inlet powered configuration. Although results at four freestream Mach numbers indicate that the exhaust plume tends to isolate the aftbody surface from most forebody flowfield differences, a smooth inlet fairing provides the least aftbody force and moment variation compared to a flowing inlet. The final objective was to predict and understand the 3D characteristics of exhaust plume development at selected points on a representative flight path. Results showed a dramatic effect of plume expansion onto the wings as the freestream Mach number and corresponding nozzle pressure ratio are increased. NomenclatureM Mach number NPR nozzle pressure ratio, p t,jet / p pressure, Pa Re Reynolds number, 1/m T temperature, K X aftbody aftbody length from cowl trailing edge to body trailing edge x, y, z streamwise, spanwise, and vertical coordinates Y aftbody model fuselage maximum semispan α angle of attack, degrees ρ density, kg/m 3 Subscripts freestream conditions throat conditions at the internal nozzle throat t, jet jet total conditions wall conditions at a solid wall boundary p ∞ ∞

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Computational flowfields for static testing of powered hypersonic aftbody models

Huebner

1993

Journal of Aircraft

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Comparison between experimental and numerical results for a researchhypersonic aircraft

Cited by 9 publications

References 2 publications

Interpretation of waverider performance data using computational fluid dynamics

Interpretation of waverider performance data using computational fluid dynamics

CFD code calibration and inlet-fairing effects on a 3D hypersonic powered-simulation model

Computational flowfields for static testing of powered hypersonic aftbody models

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