Large Eddy Simulations of Rectangular Jets in Crossflow: Effect of Hole Aspect Ratio
Large eddy simulations of rectangular jets in crossflow are performed to study the effect of hole geometry on the penetration and spread of the coolant jet. Three different holes of aspect ratio 0.5, 1.0 and 2.0 are studied. In the present study, the jet to crossflow blowing ratio is 0.5 and the jet Reynolds number is approximately 4,700.
It is observed that the dynamics of jets in crossflow are influenced significantly by the hole geometry for low jet to mainstream velocity ratios near the hole exit. The vertical penetration is greatest for the aspect ratio 2.0 and least for the aspect ratio 0.5. Dynamics of various steady as well as unsteady flow structures for different holes is markedly distinct at this Reynolds number. The separation between the leading and trailing edges of holes controls the evolution of the counter rotating vortex pair (CVP) near the jet exit. The relative strength of horseshoe vortex as compared to CVP changes with the hole geometry.
KeywordsWall Shear Stress Large Eddy Simulation Reynolds Stress Cross Flow Film Cool
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- Ajersch, P., Zhou, J.M., Ketler, S., Salcudean, M. and Gartshore, I. A. (1995), Multiple jets in a crossflow: detailed measurements and numerical simulations, ASME 95-GT-9Google Scholar
- Bardina, J. Ferziger, J.H. and Reynolds, W.C. (1983), Improved turbulence models based on large eddy simulations of homogeneous, incompressible turbulent flows. Report TF-19. Thermosciences Div., Eng., Dept. Mech. Stanford Univ.Google Scholar
- Batchelor, G.K. ( 1953), Theory of homogeneous turbulence, Cambridge University Press.Google Scholar
- Dubois, T., Jauberteau, F. and Temam, R. (1999), Dynamic multilevel methods and the numerical simulation of turbulence, Cambridge University Press.Google Scholar
- Garg, V. K., and Gaugler R. E., (1995), Effect of velocity and temperature distribution at the hole exit on film cooling of turbine blades, ASME paper 95-GT-2Google Scholar
- Garg, V. K., and Gaugier R. E. (1994), Prediction of film cooling on gas turbine airfoils, ASME paper 94-GT-2Google Scholar
- Haven, B.A. (1996), The effect of hole geometry on the near field character of crossflow jets, PhD. thesis, University of Washington.Google Scholar
- Jones, W. P. and Wille, M. (1996), Large eddy simulation of a round jet in crossflow, Engineering Turbulence Modeling and Experiments 3. Ed. Rodi, W. and Bergeles, G. pp.199–209Google Scholar
- Jordan, S.A. (1994), Use of the large eddy simulation dynamic model for turbulent shear driven cavity flows, ASME FED-Vol. 184 pp. 141–150.Google Scholar
- Kelso, R.M., Delo, C. and Smits, A.J. (1993), Unsteady wake structures in transverse jets, Fluid Dynamics Panel Symposium, UK, AGARD-CP-534.Google Scholar
- Muldoon, F. and Acharya, S. (1999), Numerical investigation of the dynamical behavior of a row of square jets in crossflow over a surface, (To be presented at ASME-IGTI99)Google Scholar
- Sykes, R. I., Lewellen, W. S. and Parker, S. F. (1986), On the vorticity dynamics of a turbulent jet in a crossflow, J. Fluid Mech. vol. 80, pp. 49–80Google Scholar
- Yuan L.L., and Street, R. L. (1996), Large Eddy Simulation of a Jet in Crossflow, ASME Fluids Engineering Division Vol. 242, pp.253–260Google Scholar