Efficient methods of discharge measurements in rivers and streams based on the probability concept

Abstract

Abstract:Regularities exist in fluid flows and can be represented by a set of constants. These constants are functions of the parameter of a probability distribution that exhibits resilience and stability under various flow conditions. Together, these regularities form a network and interact with each other, such that if one is known then the others can be determined from it. The regularities and their network explain the various fluid-flow phenomena and can be used in analysis of rivers and streams. For example, they can be used as the basis to develop simple and efficient methods of discharge measurements as presented herein, which only require velocity sampling at a single point on a water surface or a few points on a single vertical. Because of their simplicity and the short time requirement, these methods can be easily automated for collecting discharge data in unsteady, high flows that are badly needed for real-time flow forecasting and design of flood control structures, and for advancing the fundamental, scientific knowledge in hydrology.

Experimental Assessment of a 2-D Entropy-Based Model for Velocity Distribution in Open Channel Flow

“…For the sake of brevity, only the most significant data for each test were given in Table 1: the number of measurement points over the cross section, roughness configuration index c, water depth H, flow discharge Q, average and maximum velocity, entropic parameter G. The analyzed configurations provide variability in terms of flow discharge, water level, average and maximum velocity, showing also that the ratio u av /u max is fairly constant at varying the flow characteristics, as already pointed out by Chiu et al [18] and Moramarco and Singh [19]. The proposed model was also compared with the 2D distribution derived by Chiu [3,6,10]: (8) in which j is a generic isovel with velocity u, j 0 and j max are the isovels corresponding to a null and maximum velocity, respectively and M the entropic parameter.…”

Principle of maximum entropy in the estimation of suspended sediment concentration

“…They can be used as variables to characterize and compare various flows (SINGH; CUI, 2015; CHAO-LIN CHIU, 1987). Chiu et al (2005) and Minei (1999) established river flow estimation methods using the probabilistic model based on the Shannon entropy with the velocity measurement at only one point of a vertical of the river or some points of that river vertical. This greatly reduces the time and cost of sampling.…”

“…The channel section is calculated by calculating the discharge or total flow (MORIASI et al, 2007). The discharge data obtained by such methods can also be used to understand the ratios of the discharge phases occurring during unstable high flow periods, which have the forms different from those presented by the conventional classification curves obtained with constant flow periods (CHIU et al, 2005). Such advances should add scientific knowledge to hydrology and may also contribute greatly to engineering projects for flood control.…”

“…Such advances should add scientific knowledge to hydrology and may also contribute greatly to engineering projects for flood control. Once the channel section is known, the discharge or total flow is calculated (CHIU et al, 2005;MORAMARCO et al, 2013). The discharge data obtained by such methods can also be used to understand the ratios of the discharge phases occurring during unstable high flow periods, which have the forms different from those presented by the conventional classification curves obtained with constant flow periods (CHIU et al, 2005).…”

Modelagem hidrodinâmica unidimensional da passagem de onda de cheia em um córrego urbano considerando escoamento transcrítico

“…Elas são obtidas a partir dos princípios da conservação da massa e da quantidade de movimento, na sua versão unidimensional, e consideram as seguintes hipóteses: (1) distribuição de pressão hidrostática; (2) inclinação média do canal suave, podendo-se considerar que a medição vertical da profundidade é equivalente à medição perpendicular; (3) velocidade uniformemente distribuída pelo canal, ou seja, a velocidade e o nível variam apenas na direção longitudinal do canal; (4) canal prismático; (5) fluxo homogêneo e incompressível (CHAUDHRY, 1993;CHOW;MAIDMENT;MAYS, 1988). A forma diferenciável e conservativa das Equações de Saint Venant podem ser expressas como: A escolha do tipo de modelo depende do grau de importância relativo de cada termo da equação de momento.…”