Stability and Suppression of Turbulence in Relaxing Molecular Gas Flows
Stability and Suppression of Turbulence in Relaxing Molecular Gas Flows

Author: Yurii N. Grigoryev

Publisher: Springer

Published: 2017-04-08

Total Pages: 225

ISBN-13: 3319553607

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This book presents an in-depth systematic investigation of a dissipative effect which manifests itself as the growth of hydrodynamic stability and suppression of turbulence in relaxing molecular gas flows. The work describes the theoretical foundations of a new way to control stability and laminar turbulent transitions in aerodynamic flows. It develops hydrodynamic models for describing thermal nonequilibrium gas flows which allow the consideration of suppression of inviscid acoustic waves in 2D shear flows. Then, nonlinear evolution of large-scale vortices and Kelvin-Helmholtz waves in relaxing shear flows are studied. Critical Reynolds numbers in supersonic Couette flows are calculated analytically and numerically within the framework of both linear and nonlinear classical energy hydrodynamic stability theories. The calculations clearly show that the relaxation process can appreciably delay the laminar-turbulent transition. The aim of the book is to show the new dissipative effect, which can be used for flow control and laminarization. This volume will be of interest and useful to mechanical engineers, physicists, and mathematicians who specialize in hydrodynamic stability theory, turbulence, and laminarization of flows.

Flows and Chemical Reactions in Homogeneous Mixtures
Flows and Chemical Reactions in Homogeneous Mixtures

Author: Roger Prud'homme

Publisher: John Wiley & Sons

Published: 2013-10-08

Total Pages: 200

ISBN-13: 1118832663

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Flows with chemical reactions can occur in various fields such as combustion, process engineering, aeronautics, the atmospheric environment and aquatics. The examples of application chosen in this book mainly concern homogeneous reactive mixtures that can occur in propellers within the fields of process engineering and combustion: – propagation of sound and monodimensional flows in nozzles, which may include disequilibria of the internal modes of the energy of molecules; – ideal chemical reactors, stabilization of their steady operation points in the homogeneous case of a perfect mixture and classical instruments of experimental and theoretical analysis such as population balances, and the distribution of residence and passage times; – laminar and turbulent flames, separating those which are premixed from those which are not and which do not exhibit the same mechanisms, but which also occur in the case of triple flames. Flows and Chemical Reactions in Homogeneous Mixtures provides information on dimensional analysis, statistical thermodynamics with coupling between internal modes and chemical reactions, the apparition and damping of fluid turbulence as well as its statistical processing, bifurcations, flames in a confined medium and diffusion. Contents 1. Flows in Nozzles. 2. Chemical Reactors. 3. Laminar and Turbulent Flames. Appendix 1. Dimensionless Numbers, Similarity. Appendix 2. Thermodynamic Functions. Appendix 3. Concepts of Turbulence. Appendix 4. Thermodynamic functions for a mixture in disequilibrium. Appendix 5. Notion of bifurcation. Appendix 6. Confined flame. Appendix 7. Limits of Validity of the First-order Expansions for Diffusion Flames.