The Effect of Similarity Condition for the Test Results in a Wind Tunnel Test

풍동실험에서 상사조건이 실험결과에 미치는 영향에 관한 연구

  • 봉춘근 (서울시립대학교 환경공학부)
  • Published : 2000.08.01

Abstract

To set the similarity conditions between a prototype usually in the field and its reduced-scale model is a crucial part in model tests. No technique is available to keep perfect similarity for this procedure so far. The experimental work using a wind tunnel is not exceptional. based on the field measurements, the effect of stack parameters and wind conditions on the dispersion of stack plume has been investigated in the laboratory. in this paper intensive methodology is focused on matching these similarities. Due to the limitations to keep perfect similarity conditions some simplifications are involved in common. In this study geometric conditions and kinematic conditions using Froude number and Reynolds number have been con-sidered to keep the similarity conditions required. From the tests it is found that the critical Reynolds number (Recrit) is 2,700 when the height of stack discharge is 50mm. The dispersion has a similar trend for the higher Reynolds number than the critical Reynolds number. It is also found that different Froude number does not make any significant influence for the normalized tracer gas concentrations at the recipient providing the same ratio of the wind speed to the discharge speed. No significant effect of stack diameter is observed in the normalized tracer gas concentrations with the same Frounde number. The similarity conditions therefore used in this study are reliable to simulate the conditions in prototype into the wind tunnel tests.

Keywords

References

  1. Chimney Design Symposium Use of the wind tunnel to investigate the influence fo topographical feature on pollution from a tall stack Barrett, R.V.
  2. Journal of Air Pollution control Association v.15 A plume rise model compared with observations Briggs, G.A.
  3. Gas pollution discharge from boiler stacks (A wind tunnel study) Dean, M.
  4. J. of the Air Pollution Control Association v.12 Diffusion of vented gas around buildings Halitsky, J.
  5. Atmospheric Environment v.16 Wind tunnel investigation of the effects of a rectangular-shaped building on dispersion of effluents from short adjacent stacks Huber, A.H.;W.H. Snyder
  6. J. of Wind Engineering v.59 The similarity requirements for wind tunnel model studies of gas diffusion Mochida ,A.;S. Murakami;S. Kato
  7. Journal of Fluid Mechanics v.11 Measurement of entrainment of axisymetrical turbulent jets Ricou, F.P.;D.B. Spalding
  8. Mechanical Engineering v.62 The control of gases in the wake of smoke stacks Sherlok, R.H.;E.A. Stalker
  9. Report No. EPA-600/8-81-009 Guideline for fluid modeling of atmospheric diffusion Snyder, W.H.
  10. Journal of Air Pollution Control Association v.7 Atmospheric dispersal of industrial stack gases determined by concentration measurements in scale model wind tunnel experiments Storm, G.H.;M. Hackman;E.J. Kaplin