CivilToolbox Manning Pipe

Solve For:

Pipe Parameters (Input Values)

Inside Pipe Diameter D=
Depth of Flow in Pipe d=	in
Slope of Pipe S_o=	^ft /_ft
Relative Pipe Roughness n=
Flow Q=	cfs

Output

Pipe Discharge    Q=^1.49⁄_n A_w R_h^²⁄₃ S_o^½
= ^1.49⁄ ()() ^²⁄₃()^½
= cfs gpd

Pipe Flow Velocity    V = ^Q⁄_{A_w} = ⁄ = ft/s

Percent Full (Volume)    % = ^A_w⁄_{A_t} = ⁄ = %

Percent Full (Depth)    % = ^d⁄_D = ⁄ = %

Manning Equation Variables

Wetted Area of Flow A_w=½r² (α-sinα)
= ½() ²( - sin )
= ft²

Wetted Perimeter P_w=rα= ft x
= ft

Hydraulic Radius R_h=^A_w⁄ _{P_w}=^{ft
²} ⁄ _ft
= ft

Pipe Geometry Variables

Inside Radius of Pipe    r = ^D⁄₂ = ⁄₂ = ft

Flow Depth - Pipe Radius    h = d - r = - = ft

Angle #1    θ = arccos(^h⁄_r) = arccos(⁄) = rad

Angle #2    α = 2 π- 2 θ = 2 π - 2() = rad

Total Inside Pipe Area    A_t = π r² = π()² = ft²