Determination of longitudinal dispersion coefficients of a channel having rigid vegetation

Abstract

The impact of the rigid flora on longitudinal dispersion was examined in the laboratory channel located at Thapar University Patiala. The total of nine rigid plant density used with a varying diameter of 12, 16, and 20 mm. The total 27 velocities taken and the discharge is calculated using calibrated v-notch. Rhodamine dye is used as a tracer and injected in upstream of flow and collection of a sample every 1 m distance in downstream of the canal. The dispersion coefficient stands influenced by the diameter of the rigid flora. As the diameter of rigid vegetation is increased the dispersion coefficient increases and declines with increases in the density of the flora. In vegetation, the longitudinal scatter is reduced as the vegetation density increases, with a decrease of about 30% to 50% when the density is doubled. In the pollution aspect, the speed of cloud and dispersion play a vital role and as the Reynolds number value is large the speed of cloud is slow and vice-versa. The results of the experiences gained in this study are compared with the empirical relationship of different researchers. Also, the equation is developed for calculating the dispersion coefficient with rigid vegetation in the flow of the channel of varying density and diameter.