Q1: The Empirical formula for discharge over large rectangular weirs, is known as

ANS:B - Bazin formula

The Bazin formula, named after the French engineer Henri Philibert Gaspard Bazin, is an empirical equation used to estimate the discharge (flow rate) of water in an open channel or river. It is particularly applicable to uniform flow conditions where the flow is steady, the channel slope is relatively constant, and the roughness characteristics of the channel bed and banks are well-defined. The Bazin formula expresses the discharge (Q) in terms of the hydraulic radius (R), the slope of the channel (S), the roughness coefficient (C), and the channel width (B). It is typically written as: Q=C⋅B⋅R^2/3⋅S^1/2 Where:

• Q is the discharge (flow rate) in cubic meters per second (m33/s),
• C is the Bazin's roughness coefficient (dimensionless), which accounts for the channel roughness characteristics,
• B is the width of the channel (meters),
• R is the hydraulic radius of the channel (meters),
• S is the slope of the channel (dimensionless).

The hydraulic radius (R) is defined as the ratio of the cross-sectional area of flow to the wetted perimeter of the channel. It represents the effective depth of flow in the channel. The Bazin formula is based on empirical observations and experimental data collected by Bazin and others. It provides a simplified approach to estimating flow rates in open channels, particularly those with moderate to high roughness characteristics. It's important to note that the Bazin formula is empirical and its applicability can vary depending on factors such as channel geometry, flow conditions, and the presence of obstructions. Calibration and validation against field data are often necessary to ensure accurate results when using the Bazin formula in practical applications.