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SECTION 2: TRAPEZOIDAL AND CIRCULAR CHANNEL ANALYSIS PROGRAMS <br /> 2.4.3.5 Energy Head at Normal Depth <br /> The "Energy Head" of the flow is the total energy of the flow, including both <br /> potential energy and kinetic energy. In other words, the energy head is simply <br /> the sum of the water surface elevation and the velocity head. <br /> 2.4.3.6 Cross-Sectional Area of Flow at Normal Depth <br /> The cross-sectional area of flow is computed in order to provide a quick check <br /> on the other computed quantities, and also to aid in computing excavation <br /> requirements for a trapezoidal channel. The flow area of a trapezoidal channel <br /> is computed using the following formula: <br /> Flow Area — (B+T)(D/2) <br /> in which: <br /> B — Channel Bottom Width (feet) <br /> - - - T -- Top Width of Flow (feet) <br /> D — Depth of Flow (feet) <br /> The flow area for a circular channel is computed by the following formula: <br /> 2 2 2 <br /> A — (F-r) r - (F-r) + r ArcCos[(r-F)/r] <br /> in which: <br /> A — Cross-sectional Area of Flow (square feet) <br /> F — Depth of Flow (feet) <br /> r — Radius of Channel (feet) <br /> 2.4.3.7 Top Width of Flow at Normal Depth <br /> The top width of flow is computed in order to make it easier to quickly <br /> estimate the required right-of-way width for a trapezoidal channel. The top <br /> width of the channel will probably be greater than the top width of the flow, <br /> because most channels are required to have some freeboard. <br /> The top width of flow for a circular channel is computed for comparison <br /> purposes only. It is computed by the following formula: <br /> 2 2 <br /> T — 2 r - (F-r) <br /> in which: <br /> T — Top width of flow (feet) <br /> r — Radius of Channel (feet) <br /> F — Depth of Flow (feet) <br /> 2.4. 3.8 Printing Reports of Normal Depth Procedure <br /> The Normal Depth procedure can provide a complete printed report of each <br /> computation. Section 1.6 of this manual describes how to print reports. <br /> DODSON & ASSOCIATES, INC. THE DODSON HYDRAULICS LIBRARY, PAGE 18 <br />