Date of Award

4-1994

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

First Advisor

Philip Beran, PhD

Abstract

The flow about the complete Hypersonic Applied Research Technology (HART) missile is simulated for inviscid, laminar, and turbulent conditions and Mach numbers from 2 to 6. An explicit, second-order-accurate, flux-difference-splitting, algorithm is implemented and employed to solve the Navier-Stokes equations. The formulation models turbulence with the zero-equation, Baldwin-Lomax turbulence model, accounting for pressure-gradient and compressibility effects. The equations are solved using a finite-volume methodology. In the first part of the study, numerical experiments are performed using an infinitely thin-fin approximation. The aerodynamic and static-stability characteristics are investigated to determine if conventional supersonic missile configurations can be flown at Mach numbers higher than 5. The effects of nosetip blunting and boundary-layer condition are demonstrated. In addition, many unresolved issues from experimental testing of the HART missile are addressed. In the second part of the study, the effects of fin thickness and cross section are explored. A comparison is made between thin-fin results and thick-fin results to assess the impact on missile stability. The structure of the flow near the fins is significantly affected by the turbulent transport of momentum in regions of blocked cross flow. Turbulence and the blockage phenomenon cause bleeding around the fin leading edges. Ultimately, this results in lower fin effectiveness and reduced static stability. In addition, the strength and extent of the flow structures that develop in the blocked regions appear to be enhanced by fin thickness. The aerodynamic characteristics of the HART missile are predicted at Mach numbers beyond the experimental free-flight testing capabilities. The current predictions indicate that the pitching-moment coefficient decreases with increasing Mach number much less than previous numerical computations. The present results also suggest that the clipped-delta-fin configuration is stable beyond Mach 7.

AFIT Designator

AFIT-DS-AA-94-3

DTIC Accession Number

ADA280631

Comments

The author's Vita page is omitted.

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