Numerical Simulation of Unsteady Three-Dimensional Turbulent Structures in Boundary Layer Flows

Numerical Simulation of Unsteady Three-Dimensional Turbulent Structures in Boundary Layer Flows
Author: Nan S. Lui
Publisher:
Total Pages: 45
Release: 1985
Genre:
ISBN:

The capabilities for numerical simulations of the dynamical effects of the underlying structures occurring in turbulent boundary layers have been developed. A mathematically operational model of hairpin vortex, which closely resembles the experimentally observed underlying structure of wall turbulence, has been constructed and the evolution of this incipient hairpin vortex as well as the distortion of a background laminar boundary layer has been successfully simulated. The height of the incipient hairpin vortex is about 1/5 fo the local boundary layer thickness. The calculated results not only exhibit most of the prominent features associated with turbulent spots and turbulent boundary layer flows, but also reveal dynamic processes which have been very difficult to observe in experimental studies, notably, the formation and intensification of another counter rotating hairpin vortex immediately upstream of the incipient hairpin vortex. Keywords: Navier-Stokes equations; Coherent wall structure.

Frontiers in Fluid Mechanics

Frontiers in Fluid Mechanics
Author: Stephen H. Davis
Publisher: Springer Science & Business Media
Total Pages: 299
Release: 2012-12-06
Genre: Technology & Engineering
ISBN: 3642465439

Three Dimensional Interactions in High Speed Boundary Layer Flows

Three Dimensional Interactions in High Speed Boundary Layer Flows
Author: George R. Inger
Publisher:
Total Pages: 37
Release: 1985
Genre:
ISBN:

The objective of this research is the basic theoretical investigation of three-dimensional pressure, skin friction, and heat transfer disturbances in both laminar and turbulent boundary layer flows including viscous-inviscid interaction effects, separation, and reattachment. A sound understanding of these phenomena is required in modern aerodynamic design analyses of high-speed flight vehicles. The primary emphasis in these studies has been to seek a basic physical understanding of the underlying fluid behavior by means of analytically-oriented methods; in this way, the results can be used to guide and interpret concurrent experimental and computationally-oriented investigations. This inquiry has focused on two parallel paths of investigation: three-dimensional, viscous-inviscid interaction phenomena within turbulent boundary layers in supersonic flow due to impinging swept shock and/or 3-D surface deflections, and streamwise vortex-disturbance mechanisms within laminar or turbulent boundary layers that are either separated or attached.

Advances in Applied Mechanics

Advances in Applied Mechanics
Author:
Publisher: Academic Press
Total Pages: 321
Release: 1994-08-12
Genre: Science
ISBN: 0080564097

This acclaimed series provides survey articles on the present state and future direction of research in important branches of applied mechanics. Volume 31 provides the following fully referenced, and comprehensive articles:A New Integrable Shallow Water Equation discusses the initial value problem and soliton solutions for a newly discovered, completely integrable, dispersive shallow water equation as well as the elastic collision properties of the N-soliton solutionThe Onset and Development of Thermal Convection in Fully Developed Shear Flows focuses on a few basic states involving a Boussinesq fluid and fully developed forced flows, mainly of the Couette or Poiseuille typeVortex Element Methods for Flow Simulation covers vortex patches and filaments and a critical account of difficulties, limitations, and continuing efforts to improve the simulations of laminar or peturbulent flows through the use of vortex elementmethodsMicromechanics Constitutive Description of Thermoelastic Martensitic Transformations is concerned with the micromechanics description of transformation plasticity, incorporating microstructure, crystallography, thermodynamics and micromechanics into the continuum formulation of the macroscopic constitutive behavior.

Laminar-Turbulent Transition

Laminar-Turbulent Transition
Author: Ryoji Kobayashi
Publisher: Springer Science & Business Media
Total Pages: 541
Release: 2013-03-12
Genre: Technology & Engineering
ISBN: 3642797652

The International Union of Theoretical and Applied Mechanics (IUTAM) decided in 1992 to sponsor the fourth Symposium on Laminar-Turbulent Transition, Sendai/Japan, 1994. The objectives of the present Symposium were to deepen the fundamental knowledge of stability and laminar turbulent transition in three-dimensional and compressible flows and to contribute to recent developing technologies in the field. This Symposium followed the three previous IUTAM-Symposia (Stuttgart 1979, Novosibirsk 1984 and Toulouse 1989). The Scientific Committee selected two keynote lectures and 62 technical papers. The Symposium was held on the 5th to 9th of September, 1994, at the Sendai International Center in Sendai. The participants were 82 scientists from 10 countries. The keynote lectures have critically reviewed recent development of researches concerning the laminar-to-turbulent transition phenomena from the fundamental and the application aspects. Many papers presented were concerned about the detailed mechanism of the boundary layer transition (receptivity, secondary instability, turbulent spot and bypass transition). Particular emphasis was further placed on the transition of three-dimensional boundary layers on rotation systems and on swept wings. Attention was also given to compressible hypersonic flows.