Numerical Simulation Supersonic Free Shear Layers


Book Description

The objective of the current research is to study the mixing and stability characteristics of three dimensional supersonic free shear flows through a direct numerical solution of 3-D compressible flow equations. Supersonic shear flows are of interest to SCRAMJET engine designers. The successful operation of these engines requires rapid and efficient (i.e. minimum total pressure loss) mixing of supersonic airstreams and subsonic/sonic fuel streams. (jhd).




Turbulent Shear Layers in Supersonic Flow


Book Description

A good understanding of turbulent compressible flows is essential to the design and operation of high-speed vehicles. Such flows occur, for example, in the external flow over the surfaces of supersonic aircraft, and in the internal flow through the engines. Our ability to predict the aerodynamic lift, drag, propulsion and maneuverability of high-speed vehicles is crucially dependent on our knowledge of turbulent shear layers, and our understanding of their behavior in the presence of shock waves and regions of changing pressure. Turbulent Shear Layers in Supersonic Flow provides a comprehensive introduction to the field, and helps provide a basis for future work in this area. Wherever possible we use the available experimental work, and the results from numerical simulations to illustrate and develop a physical understanding of turbulent compressible flows.




Numerical Simulation Supersonic Free Shear Layers


Book Description

The objective of the current research is to study the mixing and stability characteristics of three dimensional supersonic free shear flows through a direct numerical solution of 3-D compressible flow equations. Supersonic shear flows are of interest to SCRAMJET engine designers. The successful operation of these engines requires rapid and efficient (i.e. minimum total pressure loss) mixing of supersonic airstreams and subsonic/sonic fuel streams. (jhd).




Transition and Turbulence Control


Book Description

This volume contains articles based on lectures given at the Workshop on Transition and Turbulence Control, hosted by the Institute for Mathematical Sciences, National University of Singapore, 8OCo10 December 2004. The lecturers included 13 of the worldOCOs foremost experts in the control of transitioning and turbulent flows. The chapters cover a wide range of subjects in the broad area of flow control, and will be useful to researchers working in this area in academia, government laboratories and industry. The coverage includes control theory, passive, active and reactive methods for controlling transitional and turbulent wall-bounded flows, noise suppression and mixing enhancement of supersonic turbulent jets, compliant coatings, modern flow diagnostic systems, and swept wing instabilities."







A Two-Dimensional Numerical Simulation of a Supersonic, Chemically Reacting Mixing Layer


Book Description

Research has been undertaken to achieve an improved understanding of physical phenomena present when a supersonic flow undergoes chemical reaction. A detailed understanding of supersonic reacting flows is necessary to successfully develop advanced propulsion systems now planned for use late in this century and beyond. In order to explore such flows, a study was begun to create appropriate physical models for describing supersonic combustion, and to develop accurate and efficient numerical techniques for solving the governing equations that result from these models. From this work, two computer programs were written to study reacting flows. Both programs were constructed to consider the multicomponent diffusion and convection of important chemical species, the finite rate reaction of these species, and the resulting interaction of the fluid mechanics and the chemistry. The first program employed a finite difference scheme for integrating the governing equations, whereas the second used a hybrid Chebyshev pseudospectral technique for improved accuracy. Drummond, J. Philip Langley Research Center BOUNDARY LAYERS; CHEMICAL REACTIONS; FLUID MECHANICS; MIXING; MIXING LAYERS (FLUIDS); NUMERICAL ANALYSIS; SIMULATION; SUPERSONIC FLOW; CHEBYSHEV APPROXIMATION; COMPUTER PROGRAMS; FINITE DIFFERENCE THEORY; HYPERSONIC AIRCRAFT; SUPERSONIC COMBUSTION RAMJET ENGINES...







Research on Supersonic Reacting Flows


Book Description

An experimental and computational investigation of supersonic reacting flows, with the objective of gaining a fundamental understanding of the flow physics and chemistry interactions, is in progress. During the past year, experiments were conducted in a supersonic shear flow facility to visualize the instantaneous, three-dimensional structure of the compressible mixing layer and to measure the mixing efficiency. The mixing efficiency was measured by applying a new planar laser-induced fluorescence (PLIF) technique, termed "cold chemistry." The PLIF techniques, developed previously in our laboratory, were refined to allow measurements of temperature, velocity and multiple species in transient high-speed flows. Current codes for direct numerical simulation of time-developing, three-dimensional, reacting, compressible mixing layers were adapted for a new generation of supercomputers. Previously-developed stability analyses were extended to the range of conditions being investigated in the supersonic reacting flow experiments. (AN).