Metcalfe, RW
1988-1986
Effects of Heat Release on the Large-Scale Structure in Turbulent Mixing Layers
McMurtry, P.A.; Riley, J.J. and Metcalfe, R.W.
To appear in Journal of Fluid Mechanics, 1988. Funded by NASA Lewis Research Center and Office of Naval Research.
The effects of chemical heat release on the large-scale structure in a chemically reacting, turbulent mixing layer are investigated using direct numerical simulations. Three-dimensional, time-dependent simulations are performed for a binary, single-step chemical reaction occurring across a temporally developing turbulent mixing layer. It is found that moderate heat release slows the development of the large-scale structures and shifts their wavelengths to larger scales. The resulting entrainment of reactants is reduced, decreasing the overall chemical product formation rate. The simulation results are interpreted in terms of turbulence energetics, vorticity dynamics, and stability theory. The baroclinic torque and thermal expansion in the mixing layer produce changes in the flame vortex structure that result in more diffuse vortices than in the large-scale structures. Previously unexplained anomalies observed in the mean velocity profiles of reacting jets and mixing layers are shown to result from vorticity generation by baroclinic torques.
Direct Numerical Simulations of a Reacting Mixing Layer with Chemical Heat Release
McMurtry, P.A.; Metcalfe, R.W.; Jou, W.H. and Riley, J.J.
AIAA Journal, 24, (6), 962, 1986. Funded by NASA Lewis Research Center.
To study the coupling between chemical heat release and fluid dynamics, we have performed direct numerical simulations of a two-dimensional mixing layer undergoing a simple single-step chemical reaction with heat release. The reaction is function only of the species concentrations and does not depend on temperature. We have treated the fully compressible equations, as well as an approximate set of equations that is asymptotically valid for low Mach number flows. These latter equations have the computational advantage that high-frequency acoustic waves have been filtered out, allowing much larger time steps to be taken in the numerical solution procedure. A derivation of these equations along with an outline of the numerical solution technique is given. Simulation results indicate that the rate of chemical product formed, the thickness of the mixing layer, and the dynamics are studied to analyze and interpret some effects of heat release on the fluid motion.
Metcalfe, RW
1988-1986
Effects of Heat Release on the Large-Scale Structure in Turbulent Mixing Layers
McMurtry, P.A.; Riley, J.J. and Metcalfe, R.W.
To appear in Journal of Fluid Mechanics, 1988. Funded by NASA Lewis Research Center and Office of Naval Research.
The effects of chemical heat release on the large-scale structure in a chemically reacting, turbulent mixing layer are investigated using direct numerical simulations. Three-dimensional, time-dependent simulations are performed for a binary, single-step chemical reaction occurring across a temporally developing turbulent mixing layer. It is found that moderate heat release slows the development of the large-scale structures and shifts their wavelengths to larger scales. The resulting entrainment of reactants is reduced, decreasing the overall chemical product formation rate. The simulation results are interpreted in terms of turbulence energetics, vorticity dynamics, and stability theory. The baroclinic torque and thermal expansion in the mixing layer produce changes in the flame vortex structure that result in more diffuse vortices than in the large-scale structures. Previously unexplained anomalies observed in the mean velocity profiles of reacting jets and mixing layers are shown to result from vorticity generation by baroclinic torques.
Direct Numerical Simulations of a Reacting Mixing Layer with Chemical Heat Release
McMurtry, P.A.; Metcalfe, R.W.; Jou, W.H. and Riley, J.J.
AIAA Journal, 24, (6), 962, 1986. Funded by NASA Lewis Research Center.
To study the coupling between chemical heat release and fluid dynamics, we have performed direct numerical simulations of a two-dimensional mixing layer undergoing a simple single-step chemical reaction with heat release. The reaction is function only of the species concentrations and does not depend on temperature. We have treated the fully compressible equations, as well as an approximate set of equations that is asymptotically valid for low Mach number flows. These latter equations have the computational advantage that high-frequency acoustic waves have been filtered out, allowing much larger time steps to be taken in the numerical solution procedure. A derivation of these equations along with an outline of the numerical solution technique is given. Simulation results indicate that the rate of chemical product formed, the thickness of the mixing layer, and the dynamics are studied to analyze and interpret some effects of heat release on the fluid motion.