원형관로내 층류 맥동유동의 속도와 압력 분포에 관한 연구 = Distributions of Velocity and pressure of Pulsatile Laminar Flow in a Circular Pipe

다국어 초록 (Multilingual Abstract)

In this study basic equations for the pulsatile laminar flow in a circular rigid pipe containing a slightly compressible fluid are derived and analytical solutions for the distributions of wave propagation factor K, cross-sectional mean velocity u_(m) and pressure P are schematically developed and confirmed experimentally. The pulsatile flow with 0 ≤ f ≤ 48Hz and 0 ≤ Re ≤ 2500 generated by summing the oscillatory flow made by ball valve into steady one. The wave form of pulsatile flow is described as a longitudinal wave and particle velocities measured experimentally are group velocities of the wave packet which are always smaller than phase velocities which are approximate to the sonic velocity C when the radial dispersion and wall friction are negligible. Therefore wave number is approximated to k ＝ ω/c for high angular velocity region. The axial pressures and centerline velocities were measured by strain-gage type pressure transducers and Pito-static tubes, respectively. The cross-sectional mean velocities calculated from centerline velocities with the parabolic distributions of the laminar flow and confirmed by using the ultrasonic flowmeter. We knew that axial distributions of oscillatory velocity and pressure coincide with thoeretical and depend on the Reynolds number and angular velocity.