Submergence coefficient of full-width sharp-edged broad-crested rectangular weirs

Abstract

Full-width sharp-edged broad-crested rectangular weirs in the range 0.1 < h/L ≤ 0.3 situated in rectangular channels are frequently used in submerged flow conditions. To determine the discharge for the submerged flow, submergence coefficient and modular limit shall be known. This article deals with their determination upon a theoretic derivation and experimental research. The equation for modular limit has been determined from energy balance with simplifications. To validate it, extensive experimental research was carried out. However, the derived equation is too complicated for practical use which is why it was approximated by a simple equation applicable for the limited range. The equation for submergence coefficient was derived by modifying Villemonte’s application of the principle of superposition and its coefficients were determined using the data from experimental research of many authors. The new system of equations computes the discharge more accurately than other authors’ equations, with the error of approximately ±10% in full range of the measured data.

Stage-Discharge Relationships of Broad Crested Weir for submerged Flow Condition Utilizing Incomplete Self-Similarity(ISS) Technique

“…Figure 5 Relationship between Ψ (ks/p) 1.5 and The Ratio (h 1 /p). c=0.5097 (L/p) -0.348 (13) Furthermore, the relationship between t and L/p is shown in Figure 8 to get the following equation. By substituting Eqs.…”

“…Zachoval, et al [13] dealt with the derivation of an equation for a broad-crested weir of a rounded edge on a theoretical basis and empirical study. The standard energy equilibrium limit equation was determined.…”