3-D Composite Velocity Solutions for Subsonic/transonic Flow Over Forebodies and Afterbodies

3-D Composite Velocity Solutions for Subsonic/transonic Flow Over Forebodies and Afterbodies
Author: Raymond E. Gordnier
Publisher:
Total Pages: 62
Release: 1989
Genre: Aerodynamics, Transonic
ISBN:

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A composite velocity procedure for the three-dimensional reduced Navier-Stokes equations is developed. In the spirit of matched asymptotic expansions, the velocity components are written as a combined multiplicative and additive composite of viscous like velocities (U, W) and pseudo-potential or inviscid velocities (phi sub x, phi sub y, phi sub z). The solution procedure is then consistent with both asymptotic inviscid flow and boundary layer theory. For transonic flow cases, the Enquist-Osher flux biasing scheme developed for the full potential equation is used. A quasi-conservation form of the governing equation is used in the shock region to capture the correct rotational behavior. This is combined with the standard nonconservation nonentropy generating form used in nonshock regions. The consistent strongly implicit procedure is coupled with plane relaxation to solve the discretized equations. The composites velocity procedure is coupled with plane relaxation to solve the discretized equations. The composits velocity procedure applied for the solution of three-dimensional afterbody problems.

Theoretical Calculation of Viscous-inviscid Transonic Flows

Theoretical Calculation of Viscous-inviscid Transonic Flows
Author: Tsze C. Tai
Publisher:
Total Pages: 58
Release: 1980
Genre: Viscous flow
ISBN:

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The current status of computational capabilities for calculating viscous-inviscid transonic flows other than the solution of Navier-Stokes equations is presented. Techniques for solving transonic inviscid flows and compressible integral boundary layer methods are reviewed, and systems for strong viscous-inviscid interactions are described. Generally, the transonic viscous-inviscid interaction is characterized by a subcritical boundary layer with a supersonic outer stream. The thickening boundary layer produces a pressure rise which causes further thickening of the boundary layer. The physical flow is best modeled by direct coupling of the viscous and inviscid systems to allow immediate interaction between the shock wave and the boundary layer. It appears that the method of integral relations for the outer inviscid flow, combined with an integral boundary layer scheme, possesses such a capability. To facilitate the computation, an hybrid approach to the transonic inviscid solution, which consists of the finite difference method for solving the overall transonic inviscid potential flow field and the method of integral relations for solving Euler's equation in the shock region, is suggested. Finally, the application of the steady two-dimensional methods to the quasi two-dimensional problem on axisymmetric stream surface of a cascade flow at transonic speeds is discussed. (Author).

Computation of Transonic Viscous-Inviscid Interacting Flow

Computation of Transonic Viscous-Inviscid Interacting Flow
Author: D. L. Whitfield
Publisher:
Total Pages: 6
Release: 1983
Genre:
ISBN:

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Transonic viscous-inviscid interaction is considered using the Euler and inverse compressible turbulent boundary-layer equations. Certain improvements in the inverse boundary-layer method are mentioned, along with experiences in using various Runge-Kutta schemes to solve the Euler equations. Numerical conditions imposed on the Euler equations at a surface for viscous-inviscid interaction using the method of equivalent sources are developed, and numerical solutions are presented and compared with experimental data to illustrate essential points. (Author).