Longitudinal Dispersion Coefficient in Single-Channel Streams

Abstract

Using a new channel shape equation for straight channels and a more versatile channel shape or local flow depth equation for natural streams a method is developed for prediction of the longitudinal dispersion coefficient in single-channel natural streams, including straight and meandering ones. The method involves derivation of a new triple integral expression for the longitudinal dispersion coefficient and development of an analytical method for prediction of this coefficient in natural streams. The proposed method is verified using 70 sets of field data collected from 30 streams in the United States ranging from straight manmade canals to sinuous natural rivers. The new method predicts the longitudinal dispersion coefficient, where more than 90% calculated values range from 0.5 to 2 times the observed values. The advantage of the new method is that it is capable of accurately predicting the longitudinal dispersion coefficient in single-channel natural streams without using detailed dye concentration test data. A comparison between the new method and the existing methods shows that the new method significantly improves the prediction of the longitudinal dispersion coefficient.

Mass transport of contaminated soil released into surface water by landslides (Göta River, SW Sweden)

“…There are various storage processes that influence the transport of fine particles and hence the spatial distribution of particles, which have been reported in numerous studies (see for example Atkinson and Davis, 2000;Chanson, 2004;Karwan and Saiers, 2009;Singh and Beck, 2003;Deng et al, 2001Deng et al, , 2002Bender et al, 2011;van Mazijk and Veling, 2005;Deng and Jung, 2009). Nevertheless, the study by Karwan and Saiers (2009) suggests that transient storage can often be neglected and that a model accounting for advection, dispersion, and first-order kinetic deposition only may be sufficient to describe micrometer-sized particles.…”

GA-optimized model predicts dispersion coefficient in natural channels

“…In order to obtain optimal values of the parameters (a, h, 1, d) of the above proposed Equations (Equations (2-11)) by the GA and test the performance of the equations, this study employed 80 sets of measured field data (see Appendix) from the literature (Seo & Cheong 1998;Deng et al 2001Deng et al , 2002Kashefipour & Falconer 2002). The statistics (mean, standard deviation, minimum and maximum) for each variable are also summarized in the same Appendix.…”

“…Appendix A: | Experimental data of channel characteristics, flow variables and the dispersion coefficient in natural streams (Seo & Cheong 1998;Deng et al 2001Deng et al , 2002Kashefipour & Falconer 2002)…”

“…Deng et al (2001Deng et al ( , 2002 developed theoretically based models from Equation (1). Their first model is semi-theoretical and has the form of Equation (2).…”

Development of Longitudinal Dispersion Coefficient Based on Theoretical Equation for Transverse Distribution of Stream-Wise Velocity in Open Channel : Part II. Longitudinal Dispersion Coefficient

“…주흐름의 횡 분포를 이용하여 이론적으로 1차원 종분산계수를 제안한 연구는 Fischer(1966연구는 Fischer( , 1968)로부터 비롯된다. 그의 연구 절차를 따라 Sooky(1969), Deng et al (2001), Deng et al (2002), Seo and Baek(2004) Liu(1977), Iwasa and Aya (1991), Seo and Cheong (1998), Koussis and Rodriguez-Mirasol (1998), Swamee et al (2000), Kashefipour and Falconer(2002) …”