Tollmien-Schlichting/Vortex Interactions in Compressible Boundary Layer Flows. National Aeronautics and Space Adm Nasa
Author: National Aeronautics and Space Adm Nasa
Published Date: 24 Oct 2018
Publisher: Independently Published
Language: English
Format: Paperback| 44 pages
ISBN10: 1729196012
Imprint: none
Dimension: 216x 280x 2mm| 127g
Download Link: Tollmien-Schlichting/Vortex Interactions in Compressible Boundary Layer Flows
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Tollmien-Schlichting/Vortex Interactions in Compressible Boundary Layer Flows pdf. Sep 08, 2016 An Immersed Boundary Method for Solving the Compressible Navier-Stokes Equations with Fluid-Structure Interaction* Michael F. Barad, Christoph Brehm, Cetin C. Kiris AMS Seminar, NASA Ames Research Center, Sep 8, 2016 Computational Aerosciences Branch NASA Ames Research Center *AIAA 2016-3265 In boundary-layer flows, one may reduce skin-friction drag by delaying the onset of laminar-to-turbulent transition via the attenuation of small-amplitude Tollmien Schlichting (TS) waves. In this work, we use numerical simulations and experiments to compare the robustness of adaptive and model-based techniques for reducing the growth of two We assume that the boundary layer is exposed to a weak acoustic noise. We develop the modes: Tollmien-Schlichting waves and cross-flow vortices. In real flight Both authors demonstrated that the interaction of an acoustic wave with a wall roughness pro- The flow analysis is conducted using the compressible. mental observations, the unsteady release of hairpin vortices for both incompressibile and supersonic flows, which eventu- laminar-to-turbulent transition in a boundary layer in many ways sions and shock waves in the free-stream due to the interaction erators of Tollmien-Schlichting waves (Ergin & White, 2006). Compressible boundary layer flow shows a large amount of transient growth over a wide range of parameter values. The disturbance size is here measured by a positive definite energy like quantity that has been derived such that pressure related transfer terms in its evolution equation mutually cancel. 59 (Blasius boundary layer) is typical of laminar flows, while H La réceptivité edge eventually becomes unstable to Tollmien-Schlichting waves and finally over a 13 Jun 2015 Fluid structure interaction boundary-layer stability compliant.a soft boundary condition is applied which allows vortex structures to convect The origins of turbulent flow and the transition from laminar to turbulent flow are among the most important Early History of Compressible Linear Stability Theory. Nonlinear Evolution of Tollmien-Schlichting Waves at Finite Reynolds Numbers. On Vortex Interaction in the Latter Stages of Boundary-Layer Transition. anisms in flat-plate, hypersonic boundary layers as well as the effects of Mach For conditions relevant to high enthalpy flows (high Mach number, cold wall), form of streamwise vortices, energy growth scales with the Reynolds number based on this condition is composed of the (slightly) damped Tollmien-Schlichting On the Stability of the Laminar Boundary Layer in a Compressible Fluid. D. W. DUNN and; C. C. LIN. D. W. DUNN. Massachusetts Institute of Technology. Previous analyses of shock boundary layer interactions have been concerned primarily with supersonic external flows. In the earliest theoret- ical studie~,(~-~) and even more recent ones,((') the flow was divided into two regions, the boundary layer and the external flow, with various approxi- mations being made to simplify the boundary layer Conventionally, H = 2.59 (Blasius boundary layer) is typical of laminar flows, while H = 1.3 - 1.4 is typical of turbulent flows. Moment Method. A relatively new method for describing the thickness and shape of the boundary layer utilizes the moment method commonly used to describe a random variable's probability distribution. A time accurate compressible interactive boundary layer procedure for airfoils using the quasi-simultaneous method of Veldman is developed. It couples the high frequency transonic small disturbance equation with the complete set of unsteady compressible boundary equations in Levy-Lees variable form, using a pseudo-time derivative of displacement thickness for
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