1D Manholes: Difference between revisions
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The resulting headloss value is then applied, when sub-critical flow is experienced, to the standard head loss equation, i.e. dh = K*V<sup>2</sup>/2g. Where K is the loss coefficient, V is the conduit velocity and g the gravitation constant.
The equations used for the Engelund loss approach are provided below
[[File:Engelund Equations.PNG]]
Where:
'''Q<sub>p</sub>''' = Flow in Conduit
'''Q<sub>im</sub>''' = Total flow into manhole
'''Q<sub>om</sub>''' = Total flow out of manhole
'''y<sub>i</sub>''' = Height of inlet conduit
'''y<sub>o</sub>''' = Height of outlet conduit
'''h<sub>i</sub>''' = Inlet conduit invert
'''h<sub>o</sub>''' = Outlet Conduit invert
'''θ''' = Angle in degrees of inlet conduit relative to outlet conduit(θ = 0° "when the culverts are in line," θ=90° when the outlet culvert is at right angles)
'''Q<sub>p</sub>''' = Flow in conduit outlet
'''W<sub>m</sub>''' = Flow width in manhole (1d_mh width attribute)
'''y<sub>m</sub>''' = Depth of water in manhole
'''A<sub>m</sub>''' = Flow are in manhole
'''A'<sub>m</sub>''' = Effective flow are in manhole
'''A<sub>p</sub>''' = Flow area of conduit
'''K<sub>m</sub>''' = Manhole Loss Parameter (1d_mh Km attribute)
'''K<sub>b</sub>''' = Bend Loss Coefficient (1d_nwk Form_loss attribute)
'''K<sub>f</sub>''' = Fixed Loss (1d_mh K_Fixed attribute)
'''K<sub>Bendmax</sub>''' = Upper limit to sum of K<sub>θ</sub> and K<sub>drop</sub> (1d_mh K_Bend_Max attribute)
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Below are three worked examples of the application of the Engelund method applied to a simple model for the following scenarios:
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