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Flow Characteristics of a Turbulent Pulsating Flow in a Straight Duct Connected to a Curved Duct by using an LDV  

손현철 (순천제일대학 건축설비과)
이행남 (조선대학교 기계공학과)
박길문 (조선대학교 기계공학과)
Publication Information
Korean Journal of Air-Conditioning and Refrigeration Engineering / v.15, no.3, 2003 , pp. 177-186 More about this Journal
Abstract
In the present study, the flow characteristics of developing turbulent flows are investigated at the exit region of a square cross-sectional 180" curved duct with dimensions of 40mm$\times$40mm$\times$4000mm (height $\times$ width $\times$length). Smoke particles produced from mosquito coils were used as seed particles for the LDV measurement. Experiments were carried out to measure axial velocity profiles, shear stress distributions and entrance lengths by using an LDV system and Rotating Machinery Resolver RMR with PHASE software. Experimental results clearly show that the time-averaged Reynolds number does not affect oscillatory flow characteristics because the turbulent components tend to balance the oscillatory components in the fully developed flow region. Also, the velocity profiles are in good agreement with 1/7power law such as the results of steady turbulent flows. The turbulent intensity linearly increases along the walls and is slightly higher, especially in the period of deceleration. On the other hand, the LDV measurements show that shear stress values in slightly higher in the period of deceleration due to the flow characteristics in the exit region. The entrance length where flows become stable appears at the point that is 40 times the length of hydraulic diameter.eter.
Keywords
Laser doppler velocimeter; Turbulent pulsating flow; Square duct; Entrance region; Axial velocity; Shear stress;
Citations & Related Records
Times Cited By KSCI : 4  (Citation Analysis)
연도 인용수 순위
1 A study on flow characteristics of laminar oscillatory flows in a square-sectional 180° curved duct /
[ Cho, B. G.;Park, G.M.;Bong, T.G. ] / Transactions of the KSME(B)   과학기술학회마을
2 Axial direction velocity and wall shear stress distributions of turbulent steady flow in a curved duct /
[ Lee, H. G.;Shon, H. C.;Lee, H. N.;Park, G. M. ] / Journal of KOSME   과학기술학회마을
3 The stream-line motion of fluid in a curved pipe /
[ Dean, W. R. ] / Phil Mag. S. 7
4 Pressure distributions of turbulent oscilla-tory and pulsating flow in a curved duct /
[ Sohn, H. C.;Lee, H. N.;Park, G. M. ] / Proceeding of the 1st National Congress on Fluids Engineering
5 A study on the flow char-acterstics of developing turbulent steady, turbulent oscillatory and turbulent pulsationg flows in entrance region of a curved duct /
[ Sohn, H. C. ] / Ph.D thesis, Chosun University
6 An experimental study on flow characteristics of turbulent pulsating flow in a curved duct by using LDV /
[ Lee, H. G.;Sohn, H. C.;Lee, H. N.;Park, G. M. ] / Transactions of the KSME(B)   과학기술학회마을
7 A Study Turbulent Characteristics of Developing Turbulent Steady and unsteady flows in the Entrance region of a Square Duct /
[ Koh, Y. H. ] / Ph.D thesis, Chosun University
8 Viscosity measurements of the nin-Newtonian fluid and blood by the unsteady flowconcept in the capillary tube /
[ Shu, S. H.;Cho, M. T.;Yoo, S. S. ] / Proceeding of the 1st National Congress on Fluids Engineering
9 A study on critical Dean number of steady, oscillatory and pulsating flows in curved duct /
[ Park, G. M.;Bong, T. G.;Sohn, H. C. ] / Proceeding of the KOSME Spring Annual Meeting
10 An analysis of free oscillatory flow in a U bend /
[ Ohmi, M.;Iguchi.M. ] / Journal of JSME(B)
11 Methods of estimating load in water supply systems /
[ Lee, Y. H. ] / Airconditioning and Refrigeration   과학기술학회마을
12 Personal AVAC system in intelligent buildings /
[ Jeong, K. B.;Cho, D. W. ] / Air-conditioning and Refrigeration