Supersonic Base Flow Computation Using Higher Order Closure Turbulence Models

Supersonic Base Flow Computation Using Higher Order Closure Turbulence Models PDF Author: Ching-Chang Chieng
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Category :
Languages : en
Pages :

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Supersonic Base Flow Computation Using Higher Order Closure Turbulence Models

Supersonic Base Flow Computation Using Higher Order Closure Turbulence Models PDF Author: Ching-Chang Chieng
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Numerical Computations of Supersonic Base Flow with Special Emphasis on Turbulence Modeling

Numerical Computations of Supersonic Base Flow with Special Emphasis on Turbulence Modeling PDF Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 0

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A zonal, implicit, time-marching Navier-Stokes computational technique has been used to compute the turbulent supersonic base flow over cylindrical afterbodies. A critical element of calculating such flows is the turbulence model. Various eddy viscosity turbulence models have been used in the base region flow computations. These models include two algebraic turbulence models and a two-equation k-epsilon model. The k-epsilon equations are developed in a general coordinate system and solved using an implicit algorithm. Calculations with the k-epsilon model are extended up to the wall. Flow field computations have been performed for a cylindrical afterbody at M = 2.46 and at angle of attack alpha = 0. The results are compared to the experimental data for the same conditions and the same configuration. Details of the mean flow field as well as the turbulence quantifies have been presented. In addition, the computed base pressure distribution has been compared with the experiment. In general, the k-epsilon turbulence model performs better in the near wake than the algebraic models and predicts the base pressure much better. Base flow, Base pressure, Turbulence models, Wake, Supersonic flow.

Theatrum chemicum, praecipuos electorum auctorum tractatus de chemiae et lapidis philosophici antiquitate, veritate... continens...

Theatrum chemicum, praecipuos electorum auctorum tractatus de chemiae et lapidis philosophici antiquitate, veritate... continens... PDF Author:
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Numerical Investigation of Supersonic Base Flow with Base Bleed

Numerical Investigation of Supersonic Base Flow with Base Bleed PDF Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 0

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Book Description
A zonal, implicit, time-marching Navier-Stokes computational technique has been used to compute the turbulent supersonic base flow over a cylindrical afterbody with base bleed. A critical element of calculating such flows is the turbulence model. Two eddy viscosity turbulence models have been used in the base region flow computations. These models include an algebraic turbulence model and a two-equation k-e model. The k-e equations are solved using an implicit algorithm, and calculations with the k-e model are extended up to the wall. Flow field computations have been performed for a cylindrical afterbody at M approx. = 2.46 and at an angle of attack of a = 0. The results are compared to the experimental data for the same conditions and the same configuration. Details of the mean flow field as well as the turbulence quantities have been presented. In addition, the computed base pressure distribution has been compared with the experiment. In general, the k-e turbulence model performs better in the near wake than the algebraic model and predicts the base pressure much better.

Numerical Investigation of Supersonic Base Flow with Base Bleed

Numerical Investigation of Supersonic Base Flow with Base Bleed PDF Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 40

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Book Description
A zonal, implicit, time-marching Navier-Stokes computational technique has been used to compute the turbulent supersonic base flow over a cylindrical afterbody with base bleed. A critical element of calculating such flows is the turbulence model. Two eddy viscosity turbulence models have been used in the base region flow computations. These models include an algebraic turbulence model and a two-equation k-e model. The k-e equations are solved using an implicit algorithm, and calculations with the k-e model are extended up to the wall. Flow field computations have been performed for a cylindrical afterbody at M approx. = 2.46 and at an angle of attack of a = 0. The results are compared to the experimental data for the same conditions and the same configuration. Details of the mean flow field as well as the turbulence quantities have been presented. In addition, the computed base pressure distribution has been compared with the experiment. In general, the k-e turbulence model performs better in the near wake than the algebraic model and predicts the base pressure much better.

Second-order Closure Models for Supersonic Turbulent Flows

Second-order Closure Models for Supersonic Turbulent Flows PDF Author: Charles G. Speziale
Publisher:
ISBN:
Category : Shear flow
Languages : en
Pages : 32

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RESPACE - Key Technologies for Reusable Space Systems

RESPACE - Key Technologies for Reusable Space Systems PDF Author: Ali Gülhan
Publisher: Springer Science & Business Media
ISBN: 3540778195
Category : Technology & Engineering
Languages : en
Pages : 195

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Book Description
A few years ago the Helmholtz Association (HGF) consisting of 15 research Institutions including the German Aerospace Center (DLR) started a network research program called ‘Virtual Institutes’. The basic idea of this program was to establish research groups formed by Helmholtz research centers and universities to study and develop methods or technologies for future applications and educate young scientists. It should also enable and encourage the partners of this Virtual Institute after 3 years funding to continue their cooperation in other programs. Following this HGF request and chance the DLR Windtunnel Department of the Institute of Aerodynamics and Flow Technology took the initiative and established a network with other DLR institutes and German u- versities RWTH Aachen, University of Stuttgart and Technical University Munich. The main goal of this network was to share the experience in system analysis, ae- dynamics and material science for aerospace for improving the understanding and applicability of some key technologies for future reusable space transportation s- tems. Therefore, the virtual institute was named RESPACE (Key Technologies for Re- Usable Space Systems).

Supersonic Flow Calculation Using a Reynolds-Stress and an Eddy Thermal Diffusivity Turbulence Model

Supersonic Flow Calculation Using a Reynolds-Stress and an Eddy Thermal Diffusivity Turbulence Model PDF Author: National Aeronautics and Space Administration (NASA)
Publisher: Createspace Independent Publishing Platform
ISBN: 9781722829797
Category :
Languages : en
Pages : 42

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Book Description
A second-order model for the velocity field and a two-equation model for the temperature field are used to calculate supersonic boundary layers assuming negligible real gas effects. The modeled equations are formulated on the basis of an incompressible assumption and then extended to supersonic flows by invoking Morkovin's hypothesis, which proposes that compressibility effects are completely accounted for by mean density variations alone. In order to calculate the near-wall flow accurately, correction functions are proposed to render the modeled equations asymptotically consistent with the behavior of the exact equations near a wall and, at the same time, display the proper dependence on the molecular Prandtl number. Thus formulated, the near-wall second order turbulence model for heat transfer is applicable to supersonic flows with different Prandtl numbers. The model is validated against flows with different Prandtl numbers and supersonic flows with free-stream Mach numbers as high as 10 and wall temperature ratios as low as 0.3. Among the flow cases considered, the momentum thickness Reynolds number varies from approximately 4,000 to approximately 21,000. Good correlation with measurements of mean velocity, temperature, and its variance is obtained. Discernible improvements in the law-of-the-wall are observed, especially in the range where the big-law applies. Sommer, T. P. and So, R. M. C. and Zhang, H. S. Unspecified Center NAG1-1080; RTOP 505-70-59-08...

Scientific and Technical Aerospace Reports

Scientific and Technical Aerospace Reports PDF Author:
Publisher:
ISBN:
Category : Aeronautics
Languages : en
Pages : 994

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Computation and Comparison of Efficient Turbulence Models for Aeronautics — European Research Project ETMA

Computation and Comparison of Efficient Turbulence Models for Aeronautics — European Research Project ETMA PDF Author: Alain Dervieux
Publisher: Springer Science & Business Media
ISBN: 3322898598
Category : Technology & Engineering
Languages : en
Pages : 580

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Book Description
This volume contains contributions to the BRITE-EURAM 3rd Framework Programme ETMA and extended articles of the TMA-Workshop. It focusses on turbulence modelling techniques suitable to use in typical flow configurations, with emphasis on compressibility effects and inherent unsteadiness. These methodologies are applied to the Navier-Stokes equations, involving various turbulence modelling levels from algebraic to RSM. Basic turbulent flows in aeronautics are considered; mixing layers, wall-flows (flat-plate, backward-facing step, ramp, bump), and more complex configurations (bump, aerofoil). A critical assessment of the turbulence modelling performances is offered, based on previous results and on the experimental data-base of this research programme. The ETMA results figure in the data-base constituted by all partners and organized by INRIA