On the Turbulence Properties of Channel Flows

This thesis investigates the turbulent properties of channel flows within a controlled laboratory environment. The experimental setup features a rectangular test section with dimensions of 1.45 meters in length, 20 centimeters in width, and 10 millimeters in height. Water was utilized as the working fluid, and Laser Doppler Anemometry (LDA) was employed to measure the flow velocity at various Reynolds numbers ranging from 135 to 1800. Measurements were conducted at two specific points: Point A, located 5 millimeters from the bottom center of the test section, and Point B, situated 2.5 millimeters from the bottom. Additionally, both points were positioned 83.5 centimeters along the length and at the center of the width of the test section. The primary objective of this study was to determine the velocity profiles and corresponding turbulent intensities at these points. The results indicated that the flow regime at both points transitioned from laminar (Reynolds number 135 to 650) to transitional (Reynolds number 650 to 1000), and finally to turbulent (Reynolds number above 1000). Despite higher velocities observed at Point A, Point B exhibited greater turbulent intensity. Graphs of turbulent intensity versus Reynolds number were plotted for both points, revealing distinct flow characteristics and transitions. The findings contribute to a deeper understanding of the behavior of channel flows under varying conditions, highlighting the complex interplay between velocity and turbulence. This research provides valuable insights for applications involving fluid dynamics and engineering systems, such as suction performance in water filtration experiments, which can be conducted using similar test sections.