|
|
| Line 1: |
Line 1: |
| Outlet control means that the amount of water the culvert barrel can carry is limited by the barrel and/or tailwater conditions downstream. As a result, the flow in the barrel is subcritical, and the energy equation may be used to find the upstream headwater depth. Several flow profiles are possible and are shown below and on page 32 of HDS-5. The following correlations apply to HY-8: Type A in HDS-5 is Type 4 in HY-8, Type B in HDS-5 is Type 3 in HY-8; Type C in HDS-5 is Type 6 in HY-8, Type D in HDS-5 is Type 7 in HY-8, and Type E in HDS-5 is Type 2 in HY-8. Descriptions of these flow types may be found in HY-8 by selecting the “Flow Types” button from the Culvert Summary Table. The logic for determining flow type and the headwater elevation due to outlet control is shown below from the HY-8 help file. | | Outlet control means that the amount of water the culvert barrel can carry is limited by the barrel and/or tailwater conditions downstream. As a result, the flow in the barrel is subcritical, and the energy equation may be used to find the upstream headwater depth. Several flow profiles are possible and are shown below and on page 32 of HDS-5. The following correlations apply to HY-8: Type A in HDS-5 is Type 4 in HY-8, Type B in HDS-5 is Type 3 in HY-8; Type C in HDS-5 is Type 6 in HY-8, Type D in HDS-5 is Type 7 in HY-8, and Type E in HDS-5 is Type 2 in HY-8. Descriptions of these flow types may be found in HY-8 by selecting the “Flow Types” button from the Culvert Summary Table. |
| | |
|
| |
|
|
| |
|
| |
|
| [[Image:HY8image38.gif]] | | [[Image:HY8image38.gif]] |
|
| |
|
|
| |
|
| |
| ==='''STEP'''===
| |
| #Compute critical depth (dco)
| |
| #Compute normal depth (dno)
| |
| #Compute fullflow if nomograph solution assumed "6-FFt or FFc".
| |
| #If dco > rise, assume fullflow "6-FFc".
| |
| #:If oh < ih, compute S2 curve, "5-S2n" if submerged, else "1-S2n"
| |
| #If dco < dno, assume mild slope.
| |
| #:A. If tailwater (twh) >= So(L) + rise, compute fullflow "4-FFt".
| |
| #:B. If twh >= rise, outlet submerged, assume inlet unsubmerged
| |
| #::i. Pipe flows partially full, compute M1 curve "3-M1f".
| |
| #::: Length of curve = L - (twh - rise) / So
| |
| #::: Outlet DEPTH = rise.
| |
| #::ii. If inlet submerged, full flow "6-FFt".
| |
| #:C. If twh >= dco, outlet depth = twh.
| |
| #::i. If twh is >= dno, calculate M1 curve "3-M1t"
| |
| #::: If depth = rise, fullflow from that point. "7-M1t"
| |
| #::ii. If twh is < dno, calculate M2 curve "3-M2t"
| |
| #::: If depth = rise, fullflow from that point. "7-M2t"
| |
| #:D. If twh is < dco, outlet depth = dco.
| |
| #::i. Calculate M2 curve "2-M2c".
| |
| #::: If depth = rise, fullflow from that point. "7-M2c"
| |
| #If dco >= dno, assume steep slope.
| |
| #:A. If twh is >= So(L) + rise, assume fullflow "4-FFt".
| |
| #:B. If twh is >= rise, outlet submerged, assume inlet unsubmerged.
| |
| #::i. Steep channel-hydraulic jump forms
| |
| #::ii. Calculate fullflow headwater (oh) "6-FFt or FFc"
| |
| #::iii. If oh < rise, then inlet is unsubmerged.
| |
| #:::a. Length full = (twh - rise) / So
| |
| #:::b. Calculate S1 curve "1-S1f".
| |
| #:::: If oh >= rise, inlet submerged "5-S1f".
| |
| #:::c. If oh is < twh, tailwater drowns out jump.
| |
| #:::: Calculate M1 curve "3-M1f".
| |
| #:::: If oh >= rise, inlet submerged "5-M1f".
| |
| #:C. If twh is < rise, outlet is unsubmerged, inlet can be either.
| |
| #::i. Headwater (oh) = fullflow headwater
| |
| #::: Calculate S2 curve "1-S2n" for outlet depth.
| |
| #::: If oh >= rise, inlet submerged "5-S2n"
| |
| #::ii. If twh > headwater, tailwater drowns out jump.
| |
| #::: Calculate M1 curve "3-M1t".
| |
| #::: If culvert flows part full, "7-Mit".
| |
|
| |
|
| |
|
| |
|
|
| |
|
| |
|
|
| | The logic for determining flow type due to outlet control is shown below: |
|
| |
|
| ==='''OUTLET CONTROL 'FIXES' FOLLOWING HY-8 6.1'''===
| |
|
| |
|
| : KE = KE(IC)
| |
| : A7 = 64.4: A8 = 29: A1 = 1: A2 = .25: A3 = 2: A4 = 4 / 3: A5 = 3.14159: A6 = 4
| |
| : SELECT CASE PSHAPE 'CRITICAL DEPTH
| |
| : CASE 2
| |
| :: GOSUB 6210
| |
| : CASE 1, 3 TO 10
| |
| :: GOSUB 6220
| |
| : END SELECT
| |
| : GOSUB 6280 'NORMAL DEPTH
| |
| SELECT CASE WSP$ '***added 3.1, 4.4 changed wsp
| |
| CASE "F"
| |
| : GOSUB fullflow
| |
| CASE ELSE
| |
| : SELECT CASE DCO 'changed to DCO from DNO 4.5
| |
| : CASE IS >= RISE'If Yn = to RISE, assume full. ***added >.95 3.3, revised 4.5
| |
| :: WSPTYPE$ = "FFc"
| |
| :: GOSUB fullflow
| |
| :: IF (IH + I1E) > (OH + I1E) THEN
| |
| ::: WSPTYPE$ = "S2n": GOSUB S2CURVE
| |
| ::: IF IH > RISE THEN FLTYPE = 5 ELSE FLTYPE = 1 'added 3/05 to correct FLTYPE=6
| |
| :: END IF
| |
| : CASE IS < DNO 'Mild slope
| |
| :: SELECT CASE TWH
| |
| :: CASE IS >= S0 * L + RISE 'Pipe flows full
| |
| ::: GOSUB fullflow
| |
| :: CASE IS >= RISE 'Outlet submerged, Inlet unsubmerged
| |
| ::: 'Pipe flows partially full, M1 Curve
| |
| ::: D0 = RISE
| |
| ::: LCURVE = L - (TWH - RISE) / S0: LADJ = LCURVE
| |
| ::: GOSUB M1CURVE 'M1 Profile
| |
| ::: DL = RISE: GOSUB SectionProp: VOUT = Q / AC: DOUT = RISE '***added 3.3
| |
| ::: FLTYPE = 3: WSPTYPE$ = "M1f"
| |
| :: 'Inlet unsubmerged, outlet unsubmerged
| |
| :: 'If Inlet is submerged FLTYPE = 7 is returned
| |
| :: CASE IS >= DCO
| |
| ::: SELECT CASE TWH
| |
| ::: CASE IS >= DNO
| |
| :::: FLTYPE = 3: WSPTYPE$ = "M1t"
| |
| :::: D0 = TWH: LADJ = L
| |
| :::: GOSUB M1CURVE: DL = TWH: GOSUB SectionProp: VOUT = Q / AC: DOUT = TWH
| |
| ::: CASE IS < DNO
| |
| :::: FLTYPE = 3: WSPTYPE$ = "M2t"
| |
| :::: D0 = TWH '**3.3 changed from DO=DCO
| |
| :::: GOSUB M2CURVE: DL = TWH: GOSUB SectionProp: VOUT = Q / AC: DOUT = TWH
| |
| ::: END SELECT
| |
| :: CASE IS < DCO
| |
| ::: FLTYPE = 2: WSPTYPE$ = "M2c"
| |
| ::: D0 = DCO: GOSUB M2CURVE: DL = DCO: GOSUB SectionProp: VOUT = Q / AC: DOUT = DCO
| |
| :: END SELECT 'TWH for mild slope
| |
| : CASE IS >= DNO 'Steep slope
| |
| :: SELECT CASE TWH
| |
| :: CASE IS >= S0 * L + RISE
| |
| ::: GOSUB fullflow
| |
| :: CASE IS >= RISE 'Outlet submerged, Inlet unsubmerged
| |
| ::: 'STEEP CHANNEL-HYDRAULIC JUMP FORMS
| |
| ::: IF TWH < DNO THEN TWH = DNO '***3.3 moved
| |
| ::: GOSUB fullflow
| |
| ::: IF OH < RISE THEN
| |
| :::: LFULL = (TWH - RISE) / S0
| |
| :::: D0 = RISE: LCURVE = L - LFULL
| |
| :::: GOSUB S1CURVE
| |
| :::: IF OH + I1E > TWH + I2E THEN
| |
| ::::: FLTYPE = 1: WSPTYPE$ = "S1f"
| |
| :::: ELSE
| |
| ::::: FLTYPE = 3: WSPTYPE$ = "M1t"
| |
| ::::: D0 = RISE: LADJ = L 'Tailwater drowns out jump
| |
| ::::: GOSUB M1CURVE
| |
| :::: END IF
| |
| ::: END IF
| |
| :: CASE IS < RISE 'Outlet unsubmerged, Inlet unsubmerged & submerged
| |
| ::: 'OH = IH deleted 12/05 (should check OH from M1 with IH
| |
| ::: 'IF OH + I1E > TWH + I2E THEN
| |
| ::: ' 'GOSUB fullflow 'added 45 to revise plot, deleted 61
| |
| ::: ' FLTYPE = 1: WSPTYPE$ = "S2n"
| |
| ::: ' GOSUB S2CURVE
| |
| ::: 'ELSE 'Tailwater drowns out jump
| |
| ::: ' FLTYPE = 3: WSPTYPE$ = "M1t" 'M1 profile
| |
| ::: ' D0 = TWH: LADJ = L
| |
| ::: ' GOSUB M1CURVE: DL = TWH: GOSUB SectionProp
| |
| ::: ' VOUT = Q / AC: DOUT = TWH
| |
| ::: ' 'If culvert flows part full FLTYPE = 7 is returned
| |
| ::: 'END IF
| |
| :
| |
| ::: IF TWH <= DNO THEN
| |
| :::: FLTYPE = 1: WSPTYPE$ = "S2n"
| |
| :::: GOSUB S2CURVE
| |
| ::: ELSE 'assume Tailwater forces jump calculate M1
| |
| :::: FLTYPE = 3: WSPTYPE$ = "M1t" 'M1 profile
| |
| :::: D0 = TWH: LADJ = L
| |
| :::: GOSUB M1CURVE: DL = TWH: GOSUB SectionProp
| |
| :::: VOUT = Q / AC: DOUT = TWH
| |
| :::: 'If culvert flows part full FLTYPE = 7 is returned
| |
| :::: IF IH > OH THEN 'M1 does not control calculate S2
| |
| ::::: FLTYPE = 1: WSPTYPE$ = "S2n"
| |
| ::::: GOSUB S2CURVE
| |
| :::: END IF
| |
| ::: END IF
| |
| ::: IF OH >= RISE THEN FLTYPE = 5
| |
| :: END SELECT 'TW for steep
| |
| : END SELECT 'DNO
| |
| END SELECT 'HDS5
| |
| : WSPTYPE$(0, 0) = WSPTYPE$
| |
| : RETURN
| |
|
| |
|
| | [[Image:OutletControlFlowchart.png]] |
|
| |
|
|
| |
|
|
| |
|
| {{HY8Main}} | | {{HY8Main}} |
