Stability Analysis of the Karman Boundary-Layer Flow

  • Lee, Yun-Yong (School of Mechanical Engineering, Sungkyunkwan University) ;
  • Hwang, Young-Kyu (School of Mechanical Engineering, Sungkyunkwan University)
  • Published : 2002.03.01

Abstract

The Karman boundary-layer has been numerically investigated for the disturbance wave number, wave velocity, azimuth angle and radius (Reynolds number, Re). The disturbed flow over rotating disk can lead to transition at a much lower Re than that of the well-known Type I instability. This early transition is due to the excitation of the Type II. Presented are the neutral stability results concerning these instabilities by solving newly formulated stability equations with consideration of whole convective terms. When the present numerical results are compared with the previously known results, the value of critical Re corresponding to Type I is moved from ${Re}_{c.1}$=285.3 to 270.2 and the value corresponding to Type II from ${Re}_{c.2}$=69.4 to 36.9, respectively. Also, the corresponding wave number is moved fro)m $k_1$=0.378 to 0.386 for Type I; from $k_2$=0.279 to 0.385 for Type II. For Type II, the upped limit of wave number and azimuth angle is $k_u$=0.5872, $\varepsilon_u$=$-17.5^{\circ}$, while its lower limit is near $k_u$=0, $\varepsilon_u$=$-28.4^{\circ}$. This implies that the disturbances will be relatively fast amplified at small Re and within narrow bands of wave number compared with the previous results.

Keywords

References

  1. Faller, A.J., 1991, Instability and Transition of Disturbed Flow over a Rotating Disk, J. Fluid Mech., Vol. 230, pp. 245-269
  2. Kobayashi, R., Kohama, Y. and Takamadate, Ch., 1980, Spiral Vortices in Boundary Layer Transition Regime on a Rotating Disk, Acta Mechanica, Vol. 35, pp. 71-82
  3. Kohama, Y. and Suda, K., 1993, Crossflow Instability in a Spinning Disk Boundary Layer, AIAA Journal, Vol. 31, No. 1, pp. 212-214
  4. Lilly, D. K., 1966, On the Instability of Ekman Boundary Flow, J. of the Atmospheric Science, Vol. 23, pp. 481-494
  5. Lingwood, R. J., 1996, An Experimental Study of Absolute Instability of the Rotating Disk Boundary Layer Flow, J. Fluid Mech., Vol. 314, pp, 373-405
  6. Malik, M. R., 1986, The Neutral Curve for Stationary Disturbances in Rotating Disk Flow, J. Fluid Mech., Vol. 164, pp. 275-287
  7. Smith, N. H., 1947, Exploratory Investigation of Boundary Layer Oscillations on a Rotating Disk, NACA Tech. Note 1227
  8. Wilkinson, S. P. and Malik, M. R., 1983, Stability Experiments in the Flow over a Rotating Disk, AIAA Journal, Vol. 23, pp. 588-595
  9. Sparrow, E. M. and Gregg, J. L., 1960, Mass Transfer, Flow and Heat Transfer about a Rotating Disk, Transactions ASME, J Heat Transfer, Vol. 82, pp. 294-302
  10. Faller, A. J. and Kaylor, R. E., 1966, A Numerical Study of the Instability of the Laminar Ekman Boundary Layer, J. Atmos, Sci., Vol. 23, pp. 466-480
  11. Gregory, N., Stuart, J. T. and Walker, W. S., 1955, On the Stability of Three-Dimensional Boundary Layers with Application to the Flow Due to a Rotating Disk, Phil. Trans. Roy. Soc., Vol. 248, pp. 155-199
  12. Gregory, N. and Walker, W. S., 1960, Experiments on the Effect of Suction on the Flow Due to a Rotating Disk, J. Fluid Mech., Vol. 9, pp. 225-234
  13. Malik, M. R., Wilkinson, S. P. and Orszag, S. A., 1981, Instability and Transition in Rotating Disk Flow, AIAA Journal, Vol. 19, No. 9, pp. 1131-1138
  14. Faller, A. J., Yang, S. T. and Piomelli, U., 1989, Instability of the KEB Boundary Layers, Tech. Note BN-1102, Inst. Phys, Sci. and Tech., U. of Maryland
  15. Hwang, Y- K, 1996, Stability of BuoyancyInduced Flows Adjacent to a Vertical Isothermal Surface in Cold Pure Water, KSME Journal, Vol. 10, No. 4, pp, 498-508
  16. Bader, G. and Ascher, U., 1985, A New Basis Implementation for a Mixed Order Boundary O.D.E. Solver, Tech. Rep. 85-11, Dept. of Computer Science, U. of British Columbia, Vancouver, Canada
  17. Mack, L. M., 1985, The Wave Pattern Produced by Point Source on a Rotating Disk. AIAA Aerospace Science Meeting, Jan. 14-17, Reno, Nevada, AIAA Paper 85-0490
  18. Hwang, Y.-K. and Lee, Y.-Y., 1999, A Theoretical Flow Instability of the $K{\acute{a}}rm{\acute{a}}n$ Boundary-Layer, Proceedings of the KSME 1999 Fall Annual Meeting B (Korean), pp. 737-742
  19. Tatro, P. R. and Mollo-Christensen, E. L., 1967, Experiments on Ekman Layer Instability, J Fluid Mech., Vol. 28, pp. 531-543