Author: James T. HowlettPublisher:
ISBN:
Category : Aerodynamics, Transonic
Languages : en
Pages : 44
Book Description
Calculation of Unsteady Transonic Flows with Mild Separation by Viscous-inviscid Interaction
Author: James T. HowlettPublisher:
ISBN:
Category : Aerodynamics, Transonic
Languages : en
Pages : 44
Book Description
Calculation of Unsteady Transonic Flows with Mild Separation by Viscous-Inviscid Interaction
Author: National Aeronautics and Space Adm NasaPublisher:
ISBN: 9781729430842
Category :
Languages : en
Pages : 44
Book Description
This paper presents a method for calculating viscous effects in two- and three-dimensional unsteady transonic flow fields. An integral boundary-layer method for turbulent viscous flow is coupled with the transonic small-disturbance potential equation in a quasi-steady manner. The viscous effects are modeled with Green's lag-entrainment equations for attached flow and an inverse boundary-layer method for flows that involve mild separation. The boundary-layer method is used stripwise to approximate three-dimensional effects. Applications are given for two-dimensional airfoils, aileron buzz, and a wing planform. Comparisons with inviscid calculations, other viscous calculation methods, and experimental data are presented. The results demonstrate that the present technique can economically and accurately calculate unsteady transonic flow fields that have viscous-inviscid interactions with mild flow separation. Howlett, James T. Langley Research Center RTOP 509-10-02-03...
Calculation of Unsteady Transonic Flows with Mild Separation by Viscous-inviscid Interaction
Author: James T. HowlettViscous-inviscid Interaction in Transonic Flow
Author: Laurence Byron WigtonPublisher:
ISBN:
Category :
Languages : en
Pages : 244
Book Description
The aim of this thesis is to couple an inviscid two dimensional steady transonic flow calculation with a boundary layer calculation. This interaction is especially important in transonic problems since the boundary layer has a significant effect on the inviscid portion of the flow. Here, the inviscid solution is obtained by an algorithm developed for the full potential equation by Holst and Ballhaus while the attached and separated turbulent boundary layer calculations are performed by Green's lag entrainment method. Guided by a model problem suggested by Le Balleur, a viscous-inviscid coupling algorithm is developed. Theoretical analysis indicates that it coverages rapidly for attached flows ad also performs well for separated flows. These conclusions are confirmed through a series of challenging transonic calculations involving both attached and separated flows. The coupling algorithm is remarkably stable and allows computation of coupled viscous-inviscid flows within times required to perform the inviscid calculations by themselves. (Author).
Computation of Viscous Phenomena in Unsteady Transonic Flow
Author: U. R. MullerPublisher:
ISBN:
Category :
Languages : en
Pages : 16
Book Description
Progress in the development towards a 30 viscous-inviscid strong interaction method for computing unsteady transonic wing flow is reported. In the current version, an ADI-technique for solving the 3D unsteady Transonic Small Perturbation Equation (TSP) has been extended by incorporating an unsteady 2D integral boundary layer method and then simultaneously solving the viscous and inviscid flow equations in a stripwise fashion.
Computation of Transonic Boattail Flow with Separation
Author: Richard G. WilmothPublisher:
ISBN:
Category : Aerodynamics, Transonic
Languages : en
Pages : 72
Book Description
Procedures for the Computation of Unsteady Transonic Flows Including Viscous Effects
Author: NASA Technical Paper
Author: Theoretical Calculation of Viscous-inviscid Transonic Flows
Author: Tsze C. TaiPublisher:
ISBN:
Category : Viscous flow
Languages : en
Pages : 58
Book Description
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).
Transonic Unsteady Aerodynamics and Aeroelasticity, 1987
Author: Publisher:
ISBN:
Category : Aerodynamics, Transonic
Languages : en
Pages : 684
Book Description