An Investigation of the Transonic Viscous Drag Coefficient for Axi-symmetric Bodies

An Investigation of the Transonic Viscous Drag Coefficient for Axi-symmetric Bodies
Author: Yue Sang Fan
Publisher:
Total Pages: 0
Release: 1995
Genre:
ISBN:

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Viscous drag in the transonic regime over an axi-symmetric body with a unique aft contour surface is investigated. The forebody is composed of an arbitrary ellipsoid. The unique aft contour surface has been obtained by an exact solution of the small perturbation transonic equation, using guidelines and tools developed at the Naval Postgraduate School. This unique contour allows the delay of shock formation in the aft portion, hence delaying the onset of wave drag which results in a reduction of the overall transonic pressure drag on the body. The drag coefficient thus computed is compared with another axisymmetric body with the same ellipsoid forebody but a simple boat-tailed conical afterbody. Computational Fluid Dynamics (CFD) has been used to compute the viscous flow over the two bodies at zero incidence using a Navier-Stokes flow-solver. Results obtained confirm the advantage of the special shaped afterbody over the conical afterbody by showing the delayed formation of shock waves at the aft portion in transonic flow, consequently achieving a lower maximum drag coefficient of approximately 5.5%. These results can be used in the design low pressure-drag surfaces for shapes such as missiles, projectiles, aircraft external ferry tanks and aircraft engine nacelles for improved performance within the transonic flight regime.

An Investigation of the Transonic Viscous Drag Coefficient for Axi-symmetric Bodies

An Investigation of the Transonic Viscous Drag Coefficient for Axi-symmetric Bodies
Author: Yue Sang Fan
Publisher:
Total Pages: 53
Release: 1995
Genre:
ISBN:

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Viscous drag in the transonic regime over an axi-symmetric body with a unique aft contour surface is investigated. The forebody is composed of an arbitrary ellipsoid. The unique aft contour surface has been obtained by an exact solution of the small perturbation transonic equation, using guidelines and tools developed at the Naval Postgraduate School. This unique contour allows the delay of shock formation in the aft portion, hence delaying the onset of wave drag which results in a reduction of the overall transonic pressure drag on the body. The drag coefficient thus computed is compared with another axisymmetric body with the same ellipsoid forebody but a simple boat-tailed conical afterbody. Computational Fluid Dynamics (CFD) has been used to compute the viscous flow over the two bodies at zero incidence using a Navier-Stokes flow-solver. Results obtained confirm the advantage of the special shaped afterbody over the conical afterbody by showing the delayed formation of shock waves at the aft portion in transonic flow, consequently achieving a lower maximum drag coefficient of approximately 5.5%. These results can be used in the design low pressure-drag surfaces for shapes such as missiles, projectiles, aircraft external ferry tanks and aircraft engine nacelles for improved performance within the transonic flight regime.

An Investigation of the Transonic Pressure Drag Coefficient for Axi-symmetric Bodies

An Investigation of the Transonic Pressure Drag Coefficient for Axi-symmetric Bodies
Author: Eddy Priyono
Publisher:
Total Pages: 85
Release: 1994
Genre:
ISBN:

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This thesis investigates the pressure drag coefficient in the transonic regime over an axi-symmetric body, with a set of unique contour surfaces developed in a previous thesis. The contour surfaces were obtained by an exact solution of the small perturbation transonic equation, using the guidelines and tools developed at NPS. In this work, Computational Fluid Dynamics (CFD) was not only used to compute the afterbody contour surface, but also to investigate a conical afterbody and complete bodies, which are composed of an arbitrary forebody (ellipsoid) and a variable afterbody (contour and conical). Euler as well as Navier-Stokes flow-solvers were applied to the geometries of interest, giving Mach-number contours for viscous and inviscid flow, pressure drag coefficient magnitude, and depicting shock wave location. On the basis of these results, it can be verified that our contour surface afterbodies will decrease by 15% the peak of the pressure drag coefficient (C sub d) versus Mach number curves in the transonic regime. These results can be used to design low pressure drag surfaces for such as missiles, projectiles and aircraft engine nacelles.

Transonic Off-design Drag and Performance of an Axisymmetric Inlet with 40 Percent Internal Contraction on Design

Transonic Off-design Drag and Performance of an Axisymmetric Inlet with 40 Percent Internal Contraction on Design
Author: Richard R. Woollett
Publisher:
Total Pages: 60
Release: 1974
Genre: Aerodynamics, Transonic
ISBN:

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An experimental investigation determined the drag and pressure performance of an axisymmetric supersonic inlet when operated in the transonic speed range. The inlet configuration was derived from a Mach 2.5 mixed compression inlet design with assumed variable geometry. At typical engine airflows the drag coefficient varied from 0.057 to 0.192 when the Mach number changed from 0.80 to 1.27. The presence of a wing simulator resulted in a sizable increase in total drag at Mach 1.2. This interference drag, which is roughly a 0.1 increase in drag coefficient, originates equally from an increase in both additive and cowl pressure drag.

Masters Theses in the Pure and Applied Sciences

Masters Theses in the Pure and Applied Sciences
Author: Wade H. Shafer
Publisher: Springer Science & Business Media
Total Pages: 341
Release: 2012-12-06
Genre: Science
ISBN: 1461559693

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Masters Theses in the Pure and Applied Sciences was first conceived, published, and disseminated by the Center for Information and Numerical Data Analysis and Synthesis (CINDAS)* at Purdue University in 1957, starting its coverage of theses with the academic year 1955. Beginning with Volume 13, the printing and dis semination phases of the activity were transferred to University Microfilms/Xerox of Ann Arbor, Michigan, with the thought that such an arrangement would be more beneficial to the academic and general scientific and technical community. After five years of this jOint undertaking we had concluded that it was in the interest of all concerned if the printing and distribution of the volumes were handled by an international publishing house to assure improved service and broader dissemination. Hence, starting with Volume 18, Masters Theses in the Pure and Applied Sciences has been disseminated on a worldwide basis by Plenum Publishing Corporation of New York, and in the same year the coverage was broadened to include Canadian universities. All back issues can also be ordered from Plenum. We have reported in Volume 40 (thesis year 1995) a total of 10,746 thesis titles from 19 Canadian and 144 United States universities. We are sure that this broader base for these titles reported will greatly enhance the value of this impor tant annual reference work. While Volume 40 reports theses submitted in 1995, on occasion, certain uni versities do report theses submitted in previous years but not reported at the time.

Experimental Investigation of the Effects of Viscosity on the Drag of Bodies of Revolution at a Mach Number of 1.5

Experimental Investigation of the Effects of Viscosity on the Drag of Bodies of Revolution at a Mach Number of 1.5
Author: Dean R. Chapman
Publisher:
Total Pages: 92
Release: 1947
Genre: Aerodynamics
ISBN:

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Summary: Tests were conducted to determine the effects of viscosity on the drag and base pressure characteristics of various bodies of revolution at a Mach number of 1.5. The models were tested both with smooth surfaces and with roughness added to evaluate the effects of Reynolds number for both laminar and turbulent boundary layers. The principal geometric variables investigated were after-body shape and length-diameter ratio. For most models, force tests and base pressure measurements were made over a range of Reynolds numbers, based on model length, from 0.6 million to 5.0 millions. Schlieren photographs were used to analyze the effects of viscosity on flow separation and shock-wave configuration near the base and to verify the condition of the boundary layer as deduced from force tests. The results are discussed and compared with theoretical calculations.

STAR

STAR
Author:
Publisher:
Total Pages: 1964
Release: 1964
Genre: Aeronautics
ISBN:

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