Manningtrap: Trapezoidal cross-section for the Gauckler-Manning-Strickler...
In iemisc: Irucka Embry's Miscellaneous Functions
Manningtrap R Documentation
Trapezoidal cross-section for the Gauckler-Manning-Strickler equation
Description
This function solves for one missing variable in the Gauckler-Manning-
Strickler equation for a trapezoidal cross-section and uniform flow. The
uniroot function is used to obtain the missing parameters.
Usage
Manningtrap(
Q = NULL,
n = NULL,
m = NULL,
m1 = NULL,
m2 = NULL,
Sf = NULL,
y = NULL,
b = NULL,
Temp = NULL,
units = c("SI", "Eng"),
type = c("symmetrical", "non-symmetrical"),
output = c("list", "data.table")
)
Arguments
Q
numeric vector that contains the discharge value (m^3/s or ft^3/s),
if known.
n
numeric vector that contains the Manning's roughness coefficient n,
if known.
m
numeric vector that contains the symmetric "cross-sectional side slope
of m:V (horizontal:vertical)", if known.
m1
numeric vector that contains the non-symmetric "cross-sectional side
slope of m1:V (horizontal:vertical)", if known.
m2
numeric vector that contains the non-symmetric "cross-sectional side
slope of m2:V (horizontal:vertical)", if known.
Sf
numeric vector that contains the bed slope (m/m or ft/ft),
if known.
y
numeric vector that contains the flow depth (m or ft), if known.
b
numeric vector that contains the bottom width, if known.
Temp
numeric vector that contains the temperature (degrees C or degrees
Fahrenheit), if known. Otherwise, the default value is 20 degrees Celsius
(68 degrees Fahrenheit).
units
character vector that contains the system of units [options are
SI for International System of Units or Eng for English units
(United States Customary System in the United States and Imperial Units in
the United Kingdom)]
type
character vector that contains the type of trapezoid (symmetrical
or non-symmetrical). The symmetrical trapezoid uses m while the non-
symmetrical trapezoid uses m1 and m2.
output
character vector that contains the output type, either it will
be a list or data.table. The list is
the easiest to obtain a singular value. Please see the examples and the
vignettes.
Details
Parameters Definitions from Chow pages 7, 13, 20, 22-23
"The depth of flow y is the vertical distance of the lowest point of a
channel section from the free surface."
"The top width Temp is the width of channel section at the free surface."
"The water area A is water area of the flow normal to the direction of flow."
"The wetted perimeters P is the length of the line of intersection of the
channel wetted surface with a cross-sectional plane normal to the direction
of flow."
"The hydraulic radius R is the ratio of the water area to its wetted
perimeters."
"The hydraulic radius D is the ratio of the water area to the top width."
"The section factor for critical-flow computation Z is the product of the
water area and the square root of the hydraulic depth."
"The section factor for uniform-flow computation AR^2/3 is the product of the
water area and the two-thirds power of the hydraulic radius."
"A channel built with unvarying cross section and constant bottom slope is
called a prismatic channel. Otherwise, the channel is nonprismatic."
"For any flow, the discharge Q at a channel section is expressed by Q = V A
where V is the mean velocity and A is the flow cross-sectional area normal
to the direction of the flow, since the mean velocity is defined as the
discharge divided by the cross-sectional area."
"The effect of viscosity relative to inertia can be represented by the
Reynolds number. ..."
"The effect of gravity upon the state of flow is represented by a ratio of
inertial forces to gravity forces. This ratio is given by the Froude
number. ..."
The References for the following equations, include, but are not limited to:
Chow pages 5, 7, 13, 21, 23, 28; Schall pages 4-17 and 5-5; Wikimedia
Conversion and Manning
Gauckler-Manning-Strickler equation is expressed as
V = \frac{K_n}{n}R^\frac{2}{3}S^\frac{1}{2}
- V
the mean velocity (m/s or ft/sec)
- n
Manning's roughness coefficient (dimensionless)
- R
the hydraulic radius (m or ft)
- S
the slope of the channel bed (m/m or ft/ft)
- K_n
the conversion constant – 1.0 for SI and
3.2808399 ^ (1 / 3) for English units – m^(1/3)/s or ft^(1/3)/s
This equation is also expressed as
Q = \frac{K_n}{n}\frac{A^\frac{5}{3}}{P^\frac{2}{3}}S^\frac{1}{2}
- Q
the discharge [m^3/s or ft^3/s (cfs)] is VA
- n
Manning's roughness coefficient (dimensionless)
- P
the wetted perimeters of the channel (m or ft)
- A
water area (m^2 or ft^2)
- S
the slope of the channel bed (m/m or ft/ft)
- K_n
the conversion constant – 1.0 for SI and
3.2808399 ^ (1 / 3) for English units – m^(1/3)/s or ft^(1/3)/s
Other important equations regarding the trapezoidal cross-section follow:
R = \frac{A}{P}
- R
the hydraulic radius (m or ft)
- A
water area (m^2 or ft^2)
- P
the wetted perimeters of the channel (m or ft)
A = y\left(b + my\right)
- A
water area (m^2 or ft^2)
- y
the flow depth (normal depth in this function) [m or ft]
- m
the horizontal side slope
- b
the bottom width (m or ft)
P = b + 2y\sqrt{\left(1 + m^2\right)}
- P
the wetted perimeters of the channel (m or ft)
- y
the flow depth (normal depth in this function) [m or ft]
- m
the horizontal side slope
- b
the bottom width (m or ft)
B = b + 2my
- B
the top width of the channel (m or ft)
- y
the flow depth (normal depth in this function) [m or ft]
- m
the horizontal side slope
- b
the bottom width (m or ft)
D = \frac{A}{B}
- D
the hydraulic depth (m or ft)
- A
water area (m^2 or ft^2)
- B
the top width of the channel (m or ft)
Z = \frac{[(b + my)y]^1.5}{\sqrt{b + 2my}}
- Z
the Section factor (m or ft)
- y
the flow depth (normal depth in this function) [m or ft]
- m
the horizontal side slope
- b
the bottom width (m or ft)
E = y + \frac{Q^2}{2gA^2}
- E
the Specific Energy (m or ft)
- Q
the discharge [m^3/s or ft^3/s (cfs)] is VA
- g
gravitational acceleration (m/s^2 or ft/sec^2)
- A
water area (m^2 or ft^2)
- y
the flow depth (normal depth in this function) [m or ft]
VH = \frac{V^2}{2g}
- VH
the Velocity Head (m or ft)
- V
the mean velocity (m/s or ft/sec)
- g
gravitational acceleration (m/s^2 or ft/sec^2)
w = {y}\sqrt{m^2 + 1}
- w
the Wetted Length (m or ft)
- m
the horizontal side slope
- y
the flow depth (normal depth in this function) [m or ft]
\\tau_0 = {\\gamma}{RS}
- \tau_0
"mean boundary shear stress" (N/m^2 or lbf/ft^2)
- \gamma
unit weight of water at the given temperature (N/m^3 or lbf/ft^3)
- R
the hydraulic radius (m or ft)
- S
the slope of the channel bed ["average bottom slope (equal to energy slope for uniform flow)"] (m/m or ft/ft)
\\tau_d = {\\gamma}{yS}
- \tau_d
"shear stress in channel at maximum depth" (N/m^2 or lbf/ft^2)
- \gamma
unit weight of water at the given temperature (N/m^3 or lbf/ft^3)
- y
the flow depth ("maximum depth of flow in the channel for the design discharge") [m or ft]
- S
the slope of the channel bed ["average bottom slope (equal to energy slope for uniform flow)"] (m/m or ft/ft)
# where
\\gamma = {g}{\\rho}
- \gamma
unit weight of water at the given temperature (N/m^3 or lbf/ft^3)
- g
gravitational acceleration (m/s^2 or ft/sec^2)
- \rho
density of the fluid at a certain temperature (kg/m^3 or slugs/ft^3)
\\gamma = {\\rho}\frac{g}{g_c}
- \gamma
unit weight of water at the given temperature (lbf/ft^3)
- \rho
density of the fluid at a certain temperature (lbm/ft^3)
- g
gravitational acceleration (m/s^2 or ft/sec^2)
- gc
gravitational constant (32.2 lbm-ft/lbf-sec^2) used for dimensional analysis so that the Reynolds number will be dimensionless with US Customary units
K = \frac{k(A * R ^ (2 / 3))}{n}
- K
channel conveyance (m^3/s or ft^3/sec)
- k
unit conversion factor (1 in SI and 3.2808399^(1/3) in US Customary units
- A
water area (m^2 or ft^2)
- R
the hydraulic radius (m or ft)
- n
Manning's roughness coefficient (dimensionless)
A rough turbulent zone check is performed on the water flowing in the
channel using the Reynolds number (Re). The Re equation follows:
Re = \frac{\\rho RV}{\\mu}
- Re
Reynolds number (dimensionless)
- \rho
water density (kg/m^3 or slug/ft^3)
- R
the hydraulic radius (m or ft)
- V
the mean velocity (m/s or ft/sec)
- \mu
dynamic viscosity (* 10^-3 kg/m*s or * 10^-5 lb*sec/ft^2)
A critical flow check is performed on the water flowing in the channel
using the Froude number (Fr). The Fr equation follows:
Fr = \frac{V}{\left(\sqrt{g * D}\right)}
- Fr
the Froude number (dimensionless)
- V
the mean velocity (m/s or ft/sec)
- g
gravitational acceleration (m/s^2 or ft/sec^2)
- D
the hydraulic depth (m or ft)
Value
the missing parameters (Q, n, b, m, m1, m2, Sf, or y) & V (velocity),
Flow depth (y), Bottom width (b), symmetric side slope (m), Slope (Sf),
A (area), P (wetted perimeters), R (hydraulic radius), B (top width), D
(hydraulic depth), w (Wetted Length), w1 (Wetted Length for a
non-symmetric trapezoid), w2 (Wetted Length for a non-symmetric trapezoid),
Z (Section Factor), E (Specific Energy), K (conveyance), Vel_Head (Velocity
Head), Re (Reynolds number), Fr (Froude number), taud (maximum shear
stress), tau0 (average shear stress) as a list.
Alternatively, the Flow depth (y), Flow area (A), Wetted Perimeters (P),
Top Width (B), Bottom width (b), Hydraulic Radius (R), Hydraulic Depth (D),
Flow Mean Velocity (V), Flow Discharge (Q), Manning's roughness coefficient
(n), Slope (Sf), Temperature, Absolute Temperature, Saturated Liquid
Density, Absolute or Dynamic Viscosity, Kinematic Viscosity, Froude number
(Fr), Reynolds number (Re), symmetric side slope (m), non-symmetric side
slope (m1), non-symmetric side slope (m2), Wetted Length (w), Wetted Length
for a non-symmetric trapezoid (w1), Wetted Length for a non-symmetric
trapezoid (w2), Section Factor (Z), conveyance (K), Specific Energy (E),
Velocity Head (Vel_Head), Maximum Shear Stress (taud), Average Shear Stress
(tau0) along with the associated units can be returned in a data.table.
Note
Assumption: Surface water temperature of 20 degrees Celsius (68 degrees
Fahrenheit) at atmospheric pressure
Note: Units must be consistent
Author(s)
Irucka Embry
References
Harlan Bengtson, "Calculation of Open Channel Flow Hydraulic Radius: Calculate using Trapezoid Area", Bright Hub Engineering Hydraulics in Civil Engineering, https://www.brighthubengineering.com/hydraulics-civil-engineering/67126-calculation-of-hydraulic-radius-for-uniform-open-channel-flow/.
Andrew Chadwick, John Morfett, and Martin Borthwick, Hydraulics in Civil and Environmental Engineering, Fourth Edition, New York City, New York: Spon Press, 2004, pages 132-133.
R.J. Charbeneau, "Topic 8: Open Channel Flow", CE 365K Hydraulic Engineering Design, The University of Texas at Austin Cockrell School of Engineering Department of Civil, Architectural and Environmental Engineering, https://www.caee.utexas.edu/prof/maidment/CE365KSpr14/Visual/OpenChannels.pdf.
Ven Te Chow, Ph.D., Open-Channel Hydraulics, McGraw-Hill Classic Textbook Reissue, New York City, New York: McGraw-Hill Book Company, 1988, pages 7-8, 13, 20-23, 28, 39-43.
John C. Crittenden, R. Rhodes Trussell, David W. Hand, Kerry J. Howe, George Tchobanoglous, MWH's Water Treatment: Principles and Design, Third Edition, Hoboken, New Jersey: John Wiley & Sons, Inc., 2012, pages 1861-1862.
Prof. Dr. Aminuddin Ab Ghani, "Specific Energy & Hydraulic Jump", Universiti Sains Malaysia (USM) Engineering Campus River Engineering and Urban Drainage Research Centre (REDACE), https://web.archive.org/web/20200110165556/https://redac.eng.usm.my/EAH/Handouts/Specific%20Energy%202011.pdf. Retrieved thanks to the Internet Archive: Wayback Machine
Tyler G. Hicks, P.E., Civil Engineering Formulas: Pocket Guide, 2nd Edition, New York City, New York: The McGraw-Hill Companies, Inc., 2002, pages 423, 425.
Gary P. Merkley, "BIE6300 - Irrigation & Conveyance Control Systems, Spring 2004", 2004, Biological and Irrigation Engineering - OCW. Course 2, https://digitalcommons.usu.edu/ocw_bie/2/.
Dan Moore, P.E., NRCS Water Quality and Quantity Technology Development Team, Portland Oregon, "Using Mannings Equation with Natural Streams", August 2011, https://web.archive.org/web/20210416091858/https://www.wcc.nrcs.usda.gov/ftpref/wntsc/H&H/xsec/manningsNaturally.pdf. Retrieved thanks to the Internet Archive: Wayback Machine
Robert L. Mott and Joseph A. Untener, Applied Fluid Mechanics, Seventh Edition, New York City, New York: Pearson, 2015, pages 376, 392.
The NIST Reference on Constants, Units, and Uncertainty, Fundamental Constants Data Center of the NIST Physical Measurement Laboratory, "standard acceleration of gravity g_n", https://physics.nist.gov/cgi-bin/cuu/Value?gn.
James D. Schall, Everett V. Richardson, and Johnny L. Morris, U.S. Department of Transportation Federal Highway Administration & National Highway Institute (NHI) and Office of Bridge Technology (HIBTemp), Introduction to Highway Hydraulics: Hydraulic Design Series Number 4, Fourth Edition, June 2008, pages 4-5, 4-16 - 4-17 and 5-5, https://www.fhwa.dot.gov/engineering/hydraulics/pubs/08090/HDS4_608.pdf.
Terry W. Sturm, Open Channel Hydraulics, 2nd Edition, New York City, New York: The McGraw-Hill Companies, Inc., 2010, pages 2, 8, 36, 102, 120, 153.
US Department of Transportation Federal Highway Administration (FHWA), "Urban Drainage Design Manual", Hydraulic Engineering Circular No. 22, Third Edition, Publication No. FHWA-NHI-10-009 September 2009 (Revised August 2013), pages 5-7 - 5-8, https://www.fhwa.dot.gov/engineering/hydraulics/library_arc.cfm?pub_number=22&id=140.
Ali R.Vatankhah, "Explicit solutions for critical and normal depths in trapezoidal and parabolic open channels", Ain Shams Engineering Journal, Volume 4, Issue 1, March 2013, Pages 17-23, https://www.sciencedirect.com/science/article/pii/S2090447912000329.
Wikimedia Foundation, Inc. Wikipedia, 15 May 2019, "Conversion of units", https://en.wikipedia.org/wiki/Conversion_of_units.
Wikimedia Foundation, Inc. Wikipedia, 23 May 2019, "Manning formula", https://en.wikipedia.org/wiki/Manning_formula.
See Also
Manningrect for a rectangular cross-section, Manningtri
for a triangular cross-section, Manningpara for a parabolic
cross-section, and Manningcirc for a circular cross-section.
Examples
# Example 1
library(iemisc)
# Exercise 4.1 from Sturm (page 153)
uu <- Manningtrap(Q = 3000, b = 40, m = 3, Sf = 0.002, n = 0.025,
units = "Eng", type = "symmetrical", output = "list")
# Q = 3000 cfs, b = 40 ft, m = 3, Sf = 0.002 ft/ft, n = 0.025,
# units = English units
# This will solve for y since it is missing and y will be in ft
uu$y # only returns y
uu # returns all results
# Example 2
# Please refer to the iemisc: Manning... Examples using iemiscdata
# [https://www.ecoccs.com/R_Examples/Manning_iemiscdata_Examples.pdf] and iemisc:
# Open Channel Flow Examples involving Geometric Shapes with the
# Gauckler-Manning-Strickler Equation
# [https://www.ecoccs.com/R_Examples/Open-Channel-Flow_Examples_Geometric_Shapes.pdf]
# for the cross-section examples using iemiscdata
iemisc documentation built on June 22, 2024, 9:45 a.m.
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| Manningtrap | R Documentation |
Trapezoidal cross-section for the Gauckler-Manning-Strickler equation
Description
This function solves for one missing variable in the Gauckler-Manning-
Strickler equation for a trapezoidal cross-section and uniform flow. The
uniroot function is used to obtain the missing parameters.
Usage
Manningtrap(
Q = NULL,
n = NULL,
m = NULL,
m1 = NULL,
m2 = NULL,
Sf = NULL,
y = NULL,
b = NULL,
Temp = NULL,
units = c("SI", "Eng"),
type = c("symmetrical", "non-symmetrical"),
output = c("list", "data.table")
)
Arguments
Q |
numeric vector that contains the discharge value (m^3/s or ft^3/s), if known. |
n |
numeric vector that contains the Manning's roughness coefficient n, if known. |
m |
numeric vector that contains the symmetric "cross-sectional side slope of m:V (horizontal:vertical)", if known. |
m1 |
numeric vector that contains the non-symmetric "cross-sectional side slope of m1:V (horizontal:vertical)", if known. |
m2 |
numeric vector that contains the non-symmetric "cross-sectional side slope of m2:V (horizontal:vertical)", if known. |
Sf |
numeric vector that contains the bed slope (m/m or ft/ft), if known. |
y |
numeric vector that contains the flow depth (m or ft), if known. |
b |
numeric vector that contains the bottom width, if known. |
Temp |
numeric vector that contains the temperature (degrees C or degrees Fahrenheit), if known. Otherwise, the default value is 20 degrees Celsius (68 degrees Fahrenheit). |
units |
character vector that contains the system of units [options are
|
type |
character vector that contains the type of trapezoid (symmetrical
or non-symmetrical). The symmetrical trapezoid uses |
output |
character vector that contains the output type, either it will
be a |
Details
Parameters Definitions from Chow pages 7, 13, 20, 22-23 "The depth of flow y is the vertical distance of the lowest point of a channel section from the free surface."
"The top width Temp is the width of channel section at the free surface."
"The water area A is water area of the flow normal to the direction of flow."
"The wetted perimeters P is the length of the line of intersection of the channel wetted surface with a cross-sectional plane normal to the direction of flow."
"The hydraulic radius R is the ratio of the water area to its wetted perimeters."
"The hydraulic radius D is the ratio of the water area to the top width."
"The section factor for critical-flow computation Z is the product of the water area and the square root of the hydraulic depth."
"The section factor for uniform-flow computation AR^2/3 is the product of the water area and the two-thirds power of the hydraulic radius."
"A channel built with unvarying cross section and constant bottom slope is called a prismatic channel. Otherwise, the channel is nonprismatic."
"For any flow, the discharge Q at a channel section is expressed by Q = V A where V is the mean velocity and A is the flow cross-sectional area normal to the direction of the flow, since the mean velocity is defined as the discharge divided by the cross-sectional area."
"The effect of viscosity relative to inertia can be represented by the Reynolds number. ..."
"The effect of gravity upon the state of flow is represented by a ratio of inertial forces to gravity forces. This ratio is given by the Froude number. ..."
The References for the following equations, include, but are not limited to: Chow pages 5, 7, 13, 21, 23, 28; Schall pages 4-17 and 5-5; Wikimedia Conversion and Manning
Gauckler-Manning-Strickler equation is expressed as
V = \frac{K_n}{n}R^\frac{2}{3}S^\frac{1}{2}
- V
the mean velocity (m/s or ft/sec)
- n
Manning's roughness coefficient (dimensionless)
- R
the hydraulic radius (m or ft)
- S
the slope of the channel bed (m/m or ft/ft)
- K_n
the conversion constant – 1.0 for SI and 3.2808399 ^ (1 / 3) for English units – m^(1/3)/s or ft^(1/3)/s
This equation is also expressed as
Q = \frac{K_n}{n}\frac{A^\frac{5}{3}}{P^\frac{2}{3}}S^\frac{1}{2}
- Q
the discharge [m^3/s or ft^3/s (cfs)] is VA
- n
Manning's roughness coefficient (dimensionless)
- P
the wetted perimeters of the channel (m or ft)
- A
water area (m^2 or ft^2)
- S
the slope of the channel bed (m/m or ft/ft)
- K_n
the conversion constant – 1.0 for SI and 3.2808399 ^ (1 / 3) for English units – m^(1/3)/s or ft^(1/3)/s
Other important equations regarding the trapezoidal cross-section follow:
R = \frac{A}{P}
- R
the hydraulic radius (m or ft)
- A
water area (m^2 or ft^2)
- P
the wetted perimeters of the channel (m or ft)
A = y\left(b + my\right)
- A
water area (m^2 or ft^2)
- y
the flow depth (normal depth in this function) [m or ft]
- m
the horizontal side slope
- b
the bottom width (m or ft)
P = b + 2y\sqrt{\left(1 + m^2\right)}
- P
the wetted perimeters of the channel (m or ft)
- y
the flow depth (normal depth in this function) [m or ft]
- m
the horizontal side slope
- b
the bottom width (m or ft)
B = b + 2my
- B
the top width of the channel (m or ft)
- y
the flow depth (normal depth in this function) [m or ft]
- m
the horizontal side slope
- b
the bottom width (m or ft)
D = \frac{A}{B}
- D
the hydraulic depth (m or ft)
- A
water area (m^2 or ft^2)
- B
the top width of the channel (m or ft)
Z = \frac{[(b + my)y]^1.5}{\sqrt{b + 2my}}
- Z
the Section factor (m or ft)
- y
the flow depth (normal depth in this function) [m or ft]
- m
the horizontal side slope
- b
the bottom width (m or ft)
E = y + \frac{Q^2}{2gA^2}
- E
the Specific Energy (m or ft)
- Q
the discharge [m^3/s or ft^3/s (cfs)] is VA
- g
gravitational acceleration (m/s^2 or ft/sec^2)
- A
water area (m^2 or ft^2)
- y
the flow depth (normal depth in this function) [m or ft]
VH = \frac{V^2}{2g}
- VH
the Velocity Head (m or ft)
- V
the mean velocity (m/s or ft/sec)
- g
gravitational acceleration (m/s^2 or ft/sec^2)
w = {y}\sqrt{m^2 + 1}
- w
the Wetted Length (m or ft)
- m
the horizontal side slope
- y
the flow depth (normal depth in this function) [m or ft]
\\tau_0 = {\\gamma}{RS}
- \tau_0
"mean boundary shear stress" (N/m^2 or lbf/ft^2)
- \gamma
unit weight of water at the given temperature (N/m^3 or lbf/ft^3)
- R
the hydraulic radius (m or ft)
- S
the slope of the channel bed ["average bottom slope (equal to energy slope for uniform flow)"] (m/m or ft/ft)
\\tau_d = {\\gamma}{yS}
- \tau_d
"shear stress in channel at maximum depth" (N/m^2 or lbf/ft^2)
- \gamma
unit weight of water at the given temperature (N/m^3 or lbf/ft^3)
- y
the flow depth ("maximum depth of flow in the channel for the design discharge") [m or ft]
- S
the slope of the channel bed ["average bottom slope (equal to energy slope for uniform flow)"] (m/m or ft/ft)
# where
\\gamma = {g}{\\rho}
- \gamma
unit weight of water at the given temperature (N/m^3 or lbf/ft^3)
- g
gravitational acceleration (m/s^2 or ft/sec^2)
- \rho
density of the fluid at a certain temperature (kg/m^3 or slugs/ft^3)
\\gamma = {\\rho}\frac{g}{g_c}
- \gamma
unit weight of water at the given temperature (lbf/ft^3)
- \rho
density of the fluid at a certain temperature (lbm/ft^3)
- g
gravitational acceleration (m/s^2 or ft/sec^2)
- gc
gravitational constant (32.2 lbm-ft/lbf-sec^2) used for dimensional analysis so that the Reynolds number will be dimensionless with US Customary units
K = \frac{k(A * R ^ (2 / 3))}{n}
- K
channel conveyance (m^3/s or ft^3/sec)
- k
unit conversion factor (1 in SI and 3.2808399^(1/3) in US Customary units
- A
water area (m^2 or ft^2)
- R
the hydraulic radius (m or ft)
- n
Manning's roughness coefficient (dimensionless)
A rough turbulent zone check is performed on the water flowing in the channel using the Reynolds number (Re). The Re equation follows:
Re = \frac{\\rho RV}{\\mu}
- Re
Reynolds number (dimensionless)
- \rho
water density (kg/m^3 or slug/ft^3)
- R
the hydraulic radius (m or ft)
- V
the mean velocity (m/s or ft/sec)
- \mu
dynamic viscosity (* 10^-3 kg/m*s or * 10^-5 lb*sec/ft^2)
A critical flow check is performed on the water flowing in the channel using the Froude number (Fr). The Fr equation follows:
Fr = \frac{V}{\left(\sqrt{g * D}\right)}
- Fr
the Froude number (dimensionless)
- V
the mean velocity (m/s or ft/sec)
- g
gravitational acceleration (m/s^2 or ft/sec^2)
- D
the hydraulic depth (m or ft)
Value
the missing parameters (Q, n, b, m, m1, m2, Sf, or y) & V (velocity),
Flow depth (y), Bottom width (b), symmetric side slope (m), Slope (Sf),
A (area), P (wetted perimeters), R (hydraulic radius), B (top width), D
(hydraulic depth), w (Wetted Length), w1 (Wetted Length for a
non-symmetric trapezoid), w2 (Wetted Length for a non-symmetric trapezoid),
Z (Section Factor), E (Specific Energy), K (conveyance), Vel_Head (Velocity
Head), Re (Reynolds number), Fr (Froude number), taud (maximum shear
stress), tau0 (average shear stress) as a list.
Alternatively, the Flow depth (y), Flow area (A), Wetted Perimeters (P),
Top Width (B), Bottom width (b), Hydraulic Radius (R), Hydraulic Depth (D),
Flow Mean Velocity (V), Flow Discharge (Q), Manning's roughness coefficient
(n), Slope (Sf), Temperature, Absolute Temperature, Saturated Liquid
Density, Absolute or Dynamic Viscosity, Kinematic Viscosity, Froude number
(Fr), Reynolds number (Re), symmetric side slope (m), non-symmetric side
slope (m1), non-symmetric side slope (m2), Wetted Length (w), Wetted Length
for a non-symmetric trapezoid (w1), Wetted Length for a non-symmetric
trapezoid (w2), Section Factor (Z), conveyance (K), Specific Energy (E),
Velocity Head (Vel_Head), Maximum Shear Stress (taud), Average Shear Stress
(tau0) along with the associated units can be returned in a data.table.
Note
Assumption: Surface water temperature of 20 degrees Celsius (68 degrees Fahrenheit) at atmospheric pressure
Note: Units must be consistent
Author(s)
Irucka Embry
References
Harlan Bengtson, "Calculation of Open Channel Flow Hydraulic Radius: Calculate using Trapezoid Area", Bright Hub Engineering Hydraulics in Civil Engineering, https://www.brighthubengineering.com/hydraulics-civil-engineering/67126-calculation-of-hydraulic-radius-for-uniform-open-channel-flow/.
Andrew Chadwick, John Morfett, and Martin Borthwick, Hydraulics in Civil and Environmental Engineering, Fourth Edition, New York City, New York: Spon Press, 2004, pages 132-133.
R.J. Charbeneau, "Topic 8: Open Channel Flow", CE 365K Hydraulic Engineering Design, The University of Texas at Austin Cockrell School of Engineering Department of Civil, Architectural and Environmental Engineering, https://www.caee.utexas.edu/prof/maidment/CE365KSpr14/Visual/OpenChannels.pdf.
Ven Te Chow, Ph.D., Open-Channel Hydraulics, McGraw-Hill Classic Textbook Reissue, New York City, New York: McGraw-Hill Book Company, 1988, pages 7-8, 13, 20-23, 28, 39-43.
John C. Crittenden, R. Rhodes Trussell, David W. Hand, Kerry J. Howe, George Tchobanoglous, MWH's Water Treatment: Principles and Design, Third Edition, Hoboken, New Jersey: John Wiley & Sons, Inc., 2012, pages 1861-1862.
Prof. Dr. Aminuddin Ab Ghani, "Specific Energy & Hydraulic Jump", Universiti Sains Malaysia (USM) Engineering Campus River Engineering and Urban Drainage Research Centre (REDACE), https://web.archive.org/web/20200110165556/https://redac.eng.usm.my/EAH/Handouts/Specific%20Energy%202011.pdf. Retrieved thanks to the Internet Archive: Wayback Machine
Tyler G. Hicks, P.E., Civil Engineering Formulas: Pocket Guide, 2nd Edition, New York City, New York: The McGraw-Hill Companies, Inc., 2002, pages 423, 425.
Gary P. Merkley, "BIE6300 - Irrigation & Conveyance Control Systems, Spring 2004", 2004, Biological and Irrigation Engineering - OCW. Course 2, https://digitalcommons.usu.edu/ocw_bie/2/.
Dan Moore, P.E., NRCS Water Quality and Quantity Technology Development Team, Portland Oregon, "Using Mannings Equation with Natural Streams", August 2011, https://web.archive.org/web/20210416091858/https://www.wcc.nrcs.usda.gov/ftpref/wntsc/H&H/xsec/manningsNaturally.pdf. Retrieved thanks to the Internet Archive: Wayback Machine
Robert L. Mott and Joseph A. Untener, Applied Fluid Mechanics, Seventh Edition, New York City, New York: Pearson, 2015, pages 376, 392.
The NIST Reference on Constants, Units, and Uncertainty, Fundamental Constants Data Center of the NIST Physical Measurement Laboratory, "standard acceleration of gravity g_n", https://physics.nist.gov/cgi-bin/cuu/Value?gn.
James D. Schall, Everett V. Richardson, and Johnny L. Morris, U.S. Department of Transportation Federal Highway Administration & National Highway Institute (NHI) and Office of Bridge Technology (HIBTemp), Introduction to Highway Hydraulics: Hydraulic Design Series Number 4, Fourth Edition, June 2008, pages 4-5, 4-16 - 4-17 and 5-5, https://www.fhwa.dot.gov/engineering/hydraulics/pubs/08090/HDS4_608.pdf.
Terry W. Sturm, Open Channel Hydraulics, 2nd Edition, New York City, New York: The McGraw-Hill Companies, Inc., 2010, pages 2, 8, 36, 102, 120, 153.
US Department of Transportation Federal Highway Administration (FHWA), "Urban Drainage Design Manual", Hydraulic Engineering Circular No. 22, Third Edition, Publication No. FHWA-NHI-10-009 September 2009 (Revised August 2013), pages 5-7 - 5-8, https://www.fhwa.dot.gov/engineering/hydraulics/library_arc.cfm?pub_number=22&id=140.
Ali R.Vatankhah, "Explicit solutions for critical and normal depths in trapezoidal and parabolic open channels", Ain Shams Engineering Journal, Volume 4, Issue 1, March 2013, Pages 17-23, https://www.sciencedirect.com/science/article/pii/S2090447912000329.
Wikimedia Foundation, Inc. Wikipedia, 15 May 2019, "Conversion of units", https://en.wikipedia.org/wiki/Conversion_of_units.
Wikimedia Foundation, Inc. Wikipedia, 23 May 2019, "Manning formula", https://en.wikipedia.org/wiki/Manning_formula.
See Also
Manningrect for a rectangular cross-section, Manningtri
for a triangular cross-section, Manningpara for a parabolic
cross-section, and Manningcirc for a circular cross-section.
Examples
# Example 1
library(iemisc)
# Exercise 4.1 from Sturm (page 153)
uu <- Manningtrap(Q = 3000, b = 40, m = 3, Sf = 0.002, n = 0.025,
units = "Eng", type = "symmetrical", output = "list")
# Q = 3000 cfs, b = 40 ft, m = 3, Sf = 0.002 ft/ft, n = 0.025,
# units = English units
# This will solve for y since it is missing and y will be in ft
uu$y # only returns y
uu # returns all results
# Example 2
# Please refer to the iemisc: Manning... Examples using iemiscdata
# [https://www.ecoccs.com/R_Examples/Manning_iemiscdata_Examples.pdf] and iemisc:
# Open Channel Flow Examples involving Geometric Shapes with the
# Gauckler-Manning-Strickler Equation
# [https://www.ecoccs.com/R_Examples/Open-Channel-Flow_Examples_Geometric_Shapes.pdf]
# for the cross-section examples using iemiscdata
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