Computational Investigations of High -Speed Dual -Stream Jets

A series of coaxial dual -stream jets issuing into quiescent air was investigated using Reynolds -averaged Navier -Stokes calculations with linear two -equation and nonlinear two -equation explicit algebraic stress turbulence modeling. Comparisons of calculated mean flowfield development were made with experimental data. For all cases, a single axisymmetric convergent -divergent nozzle provided a Mach 1.5 primary flow. Three conical secondary flow nozzles with outer (secondary) to inner (primary) nozz le diameter ratios of 1.4, 1.7, and 2.0 were examined. For each configuration, three subsonic secondary flow Mach numbers (0.37, 0.60, and 0.90) were investigated. A single jet case was also investigated for comparison with the coaxial arrangements. Com parisons of calculated centerline jet velocity decay, velocity profiles in the developing jet region, and potential core lengths yield reasonably good agreement with experimental data. Experimentally observed potential core lengthening with increasing cof low nozzle diameter and increasing secondary flow Mach number is also observed in the calculations. Calculated turbulent kinetic energy fields are provided in order to further characterize the development of the turbulent jet flowfields. The peak kinetic energy magnitude decreases and the location of the peak moves downstream with increasing secondary flow Mach number and increasing secondary nozzle diameter.

[1]  Christopher L. Rumsey,et al.  Effects of RANS Turbulence Modeling on Calculation of Lobed Nozzle Flowfields , 2003 .

[2]  Dimitri Papamoschou,et al.  Noise Suppression in Moderate-Speed Multistream Jets , 2002 .

[3]  K. Chien,et al.  Predictions of Channel and Boundary-Layer Flows with a Low-Reynolds-Number Turbulence Model , 1982 .

[4]  F. Menter.  Two-equation eddy-viscosity turbulence models for engineering applications , 1994 .

[5]  Christopher K. W. Tam,et al.  Fine-Scale Turbulence Noise from Dual-Stream Jets , 2004 .

[6]  L Rumsey Christopher,et al.  Recent Turbulence Model Advances Applied to Multi-Element Airfoil Computations , 2000 .

[7]  Dimitri Papamoschou,et al.  Mean Flow Development in Dual-Stream Compressible Jets , 2002 .

[8]  D. Yoder,et al.  Initial Evaluation of an Algebraic Reynolds Stress Model for Compressible Turbulent Shear Flows , 2003 .

[9]  F. Menter.  Improved two-equation k-omega turbulence models for aerodynamic flows , 1992 .

[10]  Marco Debiasi,et al.  Directional Suppression of Noise from a High-Speed Jet , 2001 .

[11]  D. Papamoschou.  AIAA 2002-3917 Engine Cycle and Exhaust Configurations for Quiet Supersonic Propulsion , 2002 .

[12]  C. Nelson,et al.  CHSSI Project CFD-7: The NPARC Alliance Flow Simulation System , 2001 .

[13]  Joseph H. Morrison,et al.  Turbulence Model Predictions of Strongly Curved Flow in a U-Duct , 2000 .

[14]  Marco Debiasi,et al.  Mach Wave Elimination Applied to Turbofan Engines , 2002 .