It is the depth of flow in a channel or culvert when the slope of the water surface and channel bottom is the same and the water depth remains constant.Normal depth occurs when gravitational force of the water is equal to the friction drag along the culvert and there is no acceleration of flow.
Normal depth is the depth of flow that would occur if the flow was uniform and steady, and is usually predicted using the Manning's Equation. Critical depth is defined as the depth of flow where energy is at a minimum for a particular discharge. Steep Slope is steeper than critical slope, normal depth is less than critical depth (y n c). The flow is supercritical and controlled upstream. S1 profiles begin with rise at the upstream end, then becomes horizontal, for example where a steep channel enters a pool. The Excel spreadsheet template at the left can be used to calculate the normal depth for uniform open channel flow in a rectangular channel. The channel width, b; Manning roughness coefficient, n; and bottom slope, S, must be specified along with the volumetric flow rate through the channel. The Excel spreadsheet template at the right can be used to calculate the normal depth for uniform open channel flow in a trapezoidal channel. In addition to the parameters in the previous section, a value is needed for the channel side slope, z, for a trapezoidal channel. The water surface profile is a measure of how the flow depth changes longitudinally. The profiles are classified based on the relationship between the actual water depth (y), the normal depth (y n) and the critical depth (y c). Steep Slope is steeper than critical slope, normal depth is less than critical depth (y n c). The flow is supercritical and controlled upstream. S1 profiles begin with rise at the upstream end, then becomes horizontal, for example where a steep channel enters a pool. Find help calculating normal depth for uniform open channel flow with the downloadable templates available in this article. We use iterative Manning equation calculations to determine the normal depth of flow that will take place for a given flow rate, in a channel of known bottom slope, size, shape, and roughness. The Excel spreadsheet template at the right can be used to calculate the normal depth for uniform open channel flow in a trapezoidal channel. In addition to the parameters in the previous section, a value is needed for the channel side slope, z, for a trapezoidal channel. Calculating Open Channel Flow/Normal Depth. The normal depth for a reach of uniform open channel flow is the flow depth that will occur for a given volumetric flow rate in a channel of known bottom slope, shape, size, and Manning roughness. The Excel spreadsheet template at the right can be used to calculate the normal depth for uniform open channel flow in a trapezoidal channel. In addition to the parameters in the previous section, a value is needed for the channel side slope, z, for a trapezoidal channel. normal depth. (fluid mechanics). The depth in an open channel at which a given flow has uniform velocity. 1  Facebook.  For the trapezoidal cross section, the maximum error of critical flow depth is less than 6 × 10 −6 % (near exact solution) and the maximum error of normal depth is less than 0.25% (very accurate solution). There is no analytical solution to explicitly compute the normal water depths in trapezoidal and parabolic open channels; also there is no analytical solution for critical depth in trapezoidal open channels. The maximum error of normal flow depth for parabolic cross section is also less than 8 × 10 −3 % (near exact solution). Proposed explicit equations have definite physical concept, high accuracy, easy calculation, and wide application range compared with the existing direct equations. There is no analytical solution to explicitly compute the normal water depths in trapezoidal and parabolic open channels; also there is no analytical solution for critical depth in trapezoidal open channels. Defining Normal Depth. Normal depth is the depth of flow in a channel or culvert when the slope of the water surface and channel bottom is the same and the water depth remains constant. Normal depth occurs when gravitational force of the water is equal to the friction drag along the culvert and there is no acceleration of flow. In culverts, water flows at normal depth when outside the influence of the inlet and outlet tailwater. Normal depth is undefined for culverts placed at horizontal or adverse slopes. FishXing uses Manning's Equation to calculate normal depth at each flow based on the channel roughness, wetted area and hydraulic radius
http://www.fsl.orst.edu/geowater/FX3/help/8_Hydraulic_Reference/Flow_Profiles.htm http://www.brighthubengineering.com/hydraulics-civil-engineering/86170-calculation-of-normal-depth-for-open-channel-flow/ http://www.fsl.orst.edu/geowater/FX3/help/8_Hydraulic_Reference/Flow_Profiles.htm http://www.brighthubengineering.com/hydraulics-civil-engineering/86170-calculation-of-normal-depth-for-open-channel-flow/ http://www.brighthubengineering.com/hydraulics-civil-engineering/86170-calculation-of-normal-depth-for-open-channel-flow/ http://encyclopedia2.thefreedictionary.com/normal+depth http://www.sciencedirect.com/science/article/pii/S2090447912000329 http://www.sciencedirect.com/science/article/pii/S2090447912000329 http://www.fsl.orst.edu/geowater/FX3/help/8_Hydraulic_Reference/Defining_NormalDepth.htm
what is normal depth