Yang1973 Function
private function Yang1973(flow, s, v, d, dp) result(tc)
compute sediment transport capacity using Yang (1973) approach (kg/s) limitation: Yang1973 equation can be applied for noncohesive natural beds with particle sizes between 0.062 mm and 2 mm, a specific gravity of 2.65 g/cm3, and a shape factor of 0.7
References:
Yang, C. T., Unit stream power and sediment transport, J. Hydraul. Div. Am. Soc. Civ. Eng., 98(HY10), 1805– 1826, 1972.
Yang, C. T., Incipient motion and sediment transport, J. Hydraul. Div. Am. Soc. Civ. Eng., 99(HY10), 1679– 1705, 1973.
Arguments
| Type | Intent | Optional | Attributes | Name | ||
|---|---|---|---|---|---|---|
| real(kind=float), | intent(in) | :: | flow |
water discharge in channel (m3/s) |
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| real(kind=float), | intent(in) | :: | s |
channel slope (m/m) |
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| real(kind=float), | intent(in) | :: | v |
water flow velocity in channel (m/s) |
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| real(kind=float), | intent(in) | :: | d |
particle size of bed material (mm) |
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| real(kind=float), | intent(in) | :: | dp |
water depth (m) |
Return Value real(kind=float)
computed transport capacity (kg/s)
Variables
| Type | Visibility | Attributes | Name | Initial | |||
|---|---|---|---|---|---|---|---|
| real(kind=float), | public | :: | I |
terms to compute transport capacity in Yang method |
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| real(kind=float), | public | :: | J |
terms to compute transport capacity in Yang method |
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| real(kind=float), | public | :: | conc |
sediment concentration (mg/l) |
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| real(kind=float), | public | :: | kVisc | = | 0.000001004 |
kinematic viscosity of water at 20 °C(m2/s) |
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| real(kind=float), | public | :: | vs |
channel Unit Stream Power (m/s) |
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| real(kind=float), | public | :: | vsCrit |
critical channel Unit Stream Power (m/s) |
Source Code
FUNCTION Yang1973 & ! (flow, s, v, d, dp) & ! RESULT (tc) IMPLICIT NONE !Arguments with intent in: REAL (KIND = float), INTENT(IN) :: flow !!water discharge in channel (m3/s) REAL (KIND = float), INTENT(IN) :: s !!channel slope (m/m) REAL (KIND = float), INTENT(IN) :: v !!water flow velocity in channel (m/s) REAL (KIND = float), INTENT(IN) :: d !!particle size of bed material (mm) REAL (KIND = float), INTENT(IN) :: dp !!water depth (m) !local declarations: REAL (KIND = float) :: tc !!computed transport capacity (kg/s) REAL (KIND = float) :: vs !! channel Unit Stream Power (m/s) REAL (KIND = float) :: vsCrit !! critical channel Unit Stream Power (m/s) REAL (KIND = float) :: kVisc = 0.000001004 !!kinematic viscosity of water at 20 °C(m2/s) REAL (KIND = float) :: I, J !! terms to compute transport capacity in Yang method REAL (KIND = float) :: conc !!sediment concentration (mg/l) !------------end of declaration------------------------------------------------ !compute channel unit stream power vs = v * s !compute channel critical unit stream power vsCrit = CriticalVelocity(d, dp, s) * s !compute I and J !I = 5.435 - 0.286 * LOG (FallVelocity(d) * (d/1000.) / kVisc) - & I = 6.0 - 0.286 * LOG (FallVelocity(d) * (d/1000.) / kVisc) - & 0.457 * LOG (ShearVelocity(dp,s)/FallVelocity(d)) !J = 1.799 - 0.409 * LOG (FallVelocity(d) * (d/1000.) / kVisc) - & J = 1.5 - 0.409 * LOG (FallVelocity(d) * (d/1000.) / kVisc) - & 0.314 * LOG (ShearVelocity(dp,s)/FallVelocity(d)) !if (isnan (I)) then ! write(*,*) 'I isnan', FallVelocity(d), ShearVelocity(dp,s) ! pause !end if ! !if (isnan (J)) then ! write(*,*) 'J isnan', FallVelocity(d), ShearVelocity(dp,s) ! pause !end if !compute sediment concentration (ppm or mg/l) IF (vs > vsCrit) THEN conc = EXP ( I + J * LOG((vs - vsCrit)/FallVelocity(d)) ) ELSE conc = 0. END IF IF (conc < 0.) THEN conc = 0. END IF !compute transport capacity (kg/s) tc = flow * conc / 1000. END FUNCTION Yang1973