ABSTRACT
This chapter investigates turbulent coherent structures in vegetated canopy open-channel flows, on the basis of flow visualization technology and digital image processing theory. Flow visualization is the process of making the physics of fluid flows visible with some special method and help to understand the specific flow structure. Flow visualization is an effective method to investigate the turbulent structure in vegetated flows. The application of visualization techniques keeps growing. Measuring range of velocity developed from natural low velocity to supersonic. The period and transfer occurred in coherent structures, described by the time series of tracer dye trajectory, are identified and characterized. Experimental consideration revealed that the coherent structure was complicated and had its partition along the depth direction. The experiments adopt dye injection technology to visualize the changing of coherent structures. The size of coherent structures in an image can be expressed as pixels.
