The experiment and analysis of transitional flow in pipe

• Published in: Journal of hydrodynamics. Series B Vol. 28; no. 2; pp. 313 - 318
• Main Author: 王军 杜广生 王京盈 耿介 李冬
• Format: Journal Article
• Language: English
• Published: Singapore Elsevier Ltd 01.04.2016; Springer Singapore; School of Energy and Power Engineering,Shandong University,Jinan 250061,China; School of Thermal Engineering,Shandong Jianzhu University,Jinan 250101,China%School of Energy and Power Engineering,Shandong University,Jinan 250061,China
• Subjects: Attenuation; Coefficients; energy coefficient; Engineering; Engineering Fluid Dynamics; flow instability; Fluid dynamics; Fluid flow; Hydrology/Water Resources; Instability; Numerical and Computational Physics; Pipe; Reynolds number; Simulation; transitional flow; velocity gradient; Walls; 实验; 激光多普勒测速仪; 管内; 衰减特性; 轴向速度; 过渡流; 速度梯度; 雷诺兹数; transitional flow; flow instability; velocity gradient; attenuation; energy coefficient
• ISSN: 1001-6058; 1878-0342
• DOI: 10.1016/S1001-6058(16)60633-9

The transitional flow in a pipe is important for delivery, but its characteristics remain to be explored. In this paper, the two-dimensional laser Doppler velocimetry (LDV) is used for the study, focusing on the attenuation characteristics of the axial velocity, the variation of the velocity gradient, the effect of the angle between the axis and the resultant velocity vector, and the relationship between the energy coefficient and the flow state. The attenuation characteristics of the axial velocity along the radial direction are obtained. It is shown that with the increase of the Reynolds number, the change rate of the velocity gradient slows down with a similar distribution, and a rapid decrease is seen in the near wall region. The amplitude and the frequency of the angular variation are obviously improved with the increase of the Reynolds number. The instability of the velocity field is enhanced with the increase of the energy coefficient.