Multipath Pipeline Problems
Fluid Mechanics · FE Reference Handbook section
Handbook notes for this section
Definitions and conditions exactly as the handbook states them.
- For pipes in parallel, the head loss is the same in each pipe.
- The total flowrate Q is the sum of the flowrates in the parallel pipes.
- The resultant force in a given direction acting on the fluid equals the rate of change of momentum of the fluid.
Core formulas for this FE topic
Definitions, applicability, units, assumptions and worked examples for each relation.
Worked exam-style examples
The four ways this section is written on the real exam — thoughts first, then equations, then substitution.
a multipath pipeline with two parallel branches around an obstruction Given flow in branch 1 (Q_1) = 0.2200 m^3/s; flow in branch 2 (Q_2) = 0.2250 m^3/s, determine the total flow (Q) in m^3/s.
Given
Find
total flow (Q), in m^3/s
Start with the thinking
- The governing relation printed in this handbook section is Multipath pipeline problems (continuity/head-loss balance).
- Everything except Q is given, so isolate Q symbolically first — never rearrange after the numbers are in.
- Tabulate each given with its unit and confirm the units are consistent with the relation before substituting.
- Multipath pipeline problems split total flow between parallel branches so head loss is equal in each path.
Figure 1 — schematic for Multipath pipeline problems (continuity/head-loss balance) — solve for total flow — Multipath Pipeline Problems
Step-by-step solution
Step 1 — State the governing relation:
Step 2 — Rearrange the relation so that Q stands alone on the left-hand side.
Step 3
Step 4 — Substitute the given values into the rearranged relation.
Step 5 — Evaluate:
Q = 0.4450\ \text{m^3/s}Step 6 — Check: returning Q = 0.4450 m^3/s to
reproduces the given quantities, and both sides carry the same units.
Why the other options are there
- 0.8900 — kept a factor of two that cancels in the correct rearrangement.
- 0.2225 — dropped that same factor in the other direction.
- 0.4895 — rounded an intermediate value before the final step.
Reference: FE Handbook — Multipath Pipeline Problems
multipath pipeline problems in a looped water distribution network Given total flow (Q) = 0.3550 m^3/s; flow in branch 2 (Q_2) = 0.0350 m^3/s, determine the flow in branch 1 (Q_1) in m^3/s.
Given
Find
flow in branch 1 (Q_1), in m^3/s
Start with the thinking
- The governing relation printed in this handbook section is Multipath pipeline problems (continuity/head-loss balance).
- Everything except Q_1 is given, so isolate Q_1 symbolically first — never rearrange after the numbers are in.
- Tabulate each given with its unit and confirm the units are consistent with the relation before substituting.
- Multipath pipeline problems split total flow between parallel branches so head loss is equal in each path.
Figure 2 — schematic for Multipath pipeline problems (continuity/head-loss balance) — solve for flow in branch 1 — Multipath Pipeline Problems (2)
Step-by-step solution
Step 1 — State the governing relation:
Step 2 — Rearrange the relation so that Q_1 stands alone on the left-hand side.
Step 3
Step 4 — Substitute the given values into the rearranged relation.
Step 5 — Evaluate:
Q_{1} = 0.3200\ \text{m^3/s}Step 6 — Check: returning Q_1 = 0.3200 m^3/s to
reproduces the given quantities, and both sides carry the same units.
Why the other options are there
- 0.6400 — kept a factor of two that cancels in the correct rearrangement.
- 0.1600 — dropped that same factor in the other direction.
- 0.3520 — rounded an intermediate value before the final step.
Reference: FE Handbook — Multipath Pipeline Problems
a multipath pipeline delivering flow to two service pipes Given total flow (Q) = 0.1000 m^3/s; flow in branch 1 (Q_1) = 0.2900 m^3/s, determine the flow in branch 2 (Q_2) in m^3/s.
Given
Find
flow in branch 2 (Q_2), in m^3/s
Start with the thinking
- The governing relation printed in this handbook section is Multipath pipeline problems (continuity/head-loss balance).
- Everything except Q_2 is given, so isolate Q_2 symbolically first — never rearrange after the numbers are in.
- Tabulate each given with its unit and confirm the units are consistent with the relation before substituting.
- Multipath pipeline problems split total flow between parallel branches so head loss is equal in each path.
Figure 3 — schematic for Multipath pipeline problems (continuity/head-loss balance) — solve for flow in branch 2 — Multipath Pipeline Problems (3)
Step-by-step solution
Step 1 — State the governing relation:
Step 2 — Rearrange the relation so that Q_2 stands alone on the left-hand side.
Step 3
Step 4 — Substitute the given values into the rearranged relation.
Step 5 — Evaluate:
Q_{2} = -0.1900\ \text{m^3/s}Step 6 — Check: returning Q_2 = -0.1900 m^3/s to
reproduces the given quantities, and both sides carry the same units.
Why the other options are there
- -0.3800 — kept a factor of two that cancels in the correct rearrangement.
- -0.0950 — dropped that same factor in the other direction.
- -0.2090 — rounded an intermediate value before the final step.
Reference: FE Handbook — Multipath Pipeline Problems
a multipath pipeline with two parallel branches around an obstruction Given flow in branch 1 (Q_1) = 0.2150 m^3/s; flow in branch 2 (Q_2) = 0.0250 m^3/s, determine the total flow (Q) in m^3/s.
Given
Find
total flow (Q), in m^3/s
Start with the thinking
- The governing relation printed in this handbook section is Multipath pipeline problems (continuity/head-loss balance).
- Everything except Q is given, so isolate Q symbolically first — never rearrange after the numbers are in.
- Tabulate each given with its unit and confirm the units are consistent with the relation before substituting.
- Multipath pipeline problems split total flow between parallel branches so head loss is equal in each path.
Figure 4 — schematic for Multipath pipeline problems (continuity/head-loss balance) — solve for total flow (case 2) — Multipath Pipeline Problems (4)
Step-by-step solution
Step 1 — State the governing relation:
Step 2 — Rearrange the relation so that Q stands alone on the left-hand side.
Step 3
Step 4 — Substitute the given values into the rearranged relation.
Step 5 — Evaluate:
Q = 0.2400\ \text{m^3/s}Step 6 — Check: returning Q = 0.2400 m^3/s to
reproduces the given quantities, and both sides carry the same units.
Why the other options are there
- 0.4800 — kept a factor of two that cancels in the correct rearrangement.
- 0.1200 — dropped that same factor in the other direction.
- 0.2640 — rounded an intermediate value before the final step.
Reference: FE Handbook — Multipath Pipeline Problems
multipath pipeline problems in a looped water distribution network Given total flow (Q) = 0.3250 m^3/s; flow in branch 2 (Q_2) = 0.1850 m^3/s, determine the flow in branch 1 (Q_1) in m^3/s.
Given
Find
flow in branch 1 (Q_1), in m^3/s
Start with the thinking
- The governing relation printed in this handbook section is Multipath pipeline problems (continuity/head-loss balance).
- Everything except Q_1 is given, so isolate Q_1 symbolically first — never rearrange after the numbers are in.
- Tabulate each given with its unit and confirm the units are consistent with the relation before substituting.
- Multipath pipeline problems split total flow between parallel branches so head loss is equal in each path.
Figure 5 — schematic for Multipath pipeline problems (continuity/head-loss balance) — solve for flow in branch 1 (case 2) — Multipath Pipeline Problems (5)
Step-by-step solution
Step 1 — State the governing relation:
Step 2 — Rearrange the relation so that Q_1 stands alone on the left-hand side.
Step 3
Step 4 — Substitute the given values into the rearranged relation.
Step 5 — Evaluate:
Q_{1} = 0.1400\ \text{m^3/s}Step 6 — Check: returning Q_1 = 0.1400 m^3/s to
reproduces the given quantities, and both sides carry the same units.
Why the other options are there
- 0.2800 — kept a factor of two that cancels in the correct rearrangement.
- 0.0700 — dropped that same factor in the other direction.
- 0.1540 — rounded an intermediate value before the final step.
Reference: FE Handbook — Multipath Pipeline Problems
a multipath pipeline delivering flow to two service pipes Given total flow (Q) = 0.1300 m^3/s; flow in branch 1 (Q_1) = 0.2850 m^3/s, determine the flow in branch 2 (Q_2) in m^3/s.
Given
Find
flow in branch 2 (Q_2), in m^3/s
Start with the thinking
- The governing relation printed in this handbook section is Multipath pipeline problems (continuity/head-loss balance).
- Everything except Q_2 is given, so isolate Q_2 symbolically first — never rearrange after the numbers are in.
- Tabulate each given with its unit and confirm the units are consistent with the relation before substituting.
- Multipath pipeline problems split total flow between parallel branches so head loss is equal in each path.
Figure 6 — schematic for Multipath pipeline problems (continuity/head-loss balance) — solve for flow in branch 2 (case 2) — Multipath Pipeline Problems (6)
Step-by-step solution
Step 1 — State the governing relation:
Step 2 — Rearrange the relation so that Q_2 stands alone on the left-hand side.
Step 3
Step 4 — Substitute the given values into the rearranged relation.
Step 5 — Evaluate:
Q_{2} = -0.1550\ \text{m^3/s}Step 6 — Check: returning Q_2 = -0.1550 m^3/s to
reproduces the given quantities, and both sides carry the same units.
Why the other options are there
- -0.3100 — kept a factor of two that cancels in the correct rearrangement.
- -0.0775 — dropped that same factor in the other direction.
- -0.1705 — rounded an intermediate value before the final step.
Reference: FE Handbook — Multipath Pipeline Problems
a multipath pipeline with two parallel branches around an obstruction Given flow in branch 1 (Q_1) = 0.2200 m^3/s; flow in branch 2 (Q_2) = 0.0750 m^3/s, determine the total flow (Q) in m^3/s.
Given
Find
total flow (Q), in m^3/s
Start with the thinking
- The governing relation printed in this handbook section is Multipath pipeline problems (continuity/head-loss balance).
- Everything except Q is given, so isolate Q symbolically first — never rearrange after the numbers are in.
- Tabulate each given with its unit and confirm the units are consistent with the relation before substituting.
- Multipath pipeline problems split total flow between parallel branches so head loss is equal in each path.
Figure 7 — schematic for Multipath pipeline problems (continuity/head-loss balance) — solve for total flow (case 3) — Multipath Pipeline Problems (7)
Step-by-step solution
Step 1 — State the governing relation:
Step 2 — Rearrange the relation so that Q stands alone on the left-hand side.
Step 3
Step 4 — Substitute the given values into the rearranged relation.
Step 5 — Evaluate:
Q = 0.2950\ \text{m^3/s}Step 6 — Check: returning Q = 0.2950 m^3/s to
reproduces the given quantities, and both sides carry the same units.
Why the other options are there
- 0.5900 — kept a factor of two that cancels in the correct rearrangement.
- 0.1475 — dropped that same factor in the other direction.
- 0.3245 — rounded an intermediate value before the final step.
Reference: FE Handbook — Multipath Pipeline Problems
multipath pipeline problems in a looped water distribution network Given total flow (Q) = 0.5000 m^3/s; flow in branch 2 (Q_2) = 0.1700 m^3/s, determine the flow in branch 1 (Q_1) in m^3/s.
Given
Find
flow in branch 1 (Q_1), in m^3/s
Start with the thinking
- The governing relation printed in this handbook section is Multipath pipeline problems (continuity/head-loss balance).
- Everything except Q_1 is given, so isolate Q_1 symbolically first — never rearrange after the numbers are in.
- Tabulate each given with its unit and confirm the units are consistent with the relation before substituting.
- Multipath pipeline problems split total flow between parallel branches so head loss is equal in each path.
Figure 8 — schematic for Multipath pipeline problems (continuity/head-loss balance) — solve for flow in branch 1 (case 3) — Multipath Pipeline Problems (8)
Step-by-step solution
Step 1 — State the governing relation:
Step 2 — Rearrange the relation so that Q_1 stands alone on the left-hand side.
Step 3
Step 4 — Substitute the given values into the rearranged relation.
Step 5 — Evaluate:
Q_{1} = 0.3300\ \text{m^3/s}Step 6 — Check: returning Q_1 = 0.3300 m^3/s to
reproduces the given quantities, and both sides carry the same units.
Why the other options are there
- 0.6600 — kept a factor of two that cancels in the correct rearrangement.
- 0.1650 — dropped that same factor in the other direction.
- 0.3630 — rounded an intermediate value before the final step.
Reference: FE Handbook — Multipath Pipeline Problems
a multipath pipeline delivering flow to two service pipes Given total flow (Q) = 0.0550 m^3/s; flow in branch 1 (Q_1) = 0.1300 m^3/s, determine the flow in branch 2 (Q_2) in m^3/s.
Given
Find
flow in branch 2 (Q_2), in m^3/s
Start with the thinking
- The governing relation printed in this handbook section is Multipath pipeline problems (continuity/head-loss balance).
- Everything except Q_2 is given, so isolate Q_2 symbolically first — never rearrange after the numbers are in.
- Tabulate each given with its unit and confirm the units are consistent with the relation before substituting.
- Multipath pipeline problems split total flow between parallel branches so head loss is equal in each path.
Figure 9 — schematic for Multipath pipeline problems (continuity/head-loss balance) — solve for flow in branch 2 (case 3) — Multipath Pipeline Problems (9)
Step-by-step solution
Step 1 — State the governing relation:
Step 2 — Rearrange the relation so that Q_2 stands alone on the left-hand side.
Step 3
Step 4 — Substitute the given values into the rearranged relation.
Step 5 — Evaluate:
Q_{2} = -0.0750\ \text{m^3/s}Step 6 — Check: returning Q_2 = -0.0750 m^3/s to
reproduces the given quantities, and both sides carry the same units.
Why the other options are there
- -0.1500 — kept a factor of two that cancels in the correct rearrangement.
- -0.0375 — dropped that same factor in the other direction.
- -0.0825 — rounded an intermediate value before the final step.
Reference: FE Handbook — Multipath Pipeline Problems
a multipath pipeline with two parallel branches around an obstruction Given flow in branch 1 (Q_1) = 0.2400 m^3/s; flow in branch 2 (Q_2) = 0.1150 m^3/s, determine the total flow (Q) in m^3/s.
Given
Find
total flow (Q), in m^3/s
Start with the thinking
- The governing relation printed in this handbook section is Multipath pipeline problems (continuity/head-loss balance).
- Everything except Q is given, so isolate Q symbolically first — never rearrange after the numbers are in.
- Tabulate each given with its unit and confirm the units are consistent with the relation before substituting.
- Multipath pipeline problems split total flow between parallel branches so head loss is equal in each path.
Figure 10 — schematic for Multipath pipeline problems (continuity/head-loss balance) — solve for total flow (case 4) — Multipath Pipeline Problems (10)
Step-by-step solution
Step 1 — State the governing relation:
Step 2 — Rearrange the relation so that Q stands alone on the left-hand side.
Step 3
Step 4 — Substitute the given values into the rearranged relation.
Step 5 — Evaluate:
Q = 0.3550\ \text{m^3/s}Step 6 — Check: returning Q = 0.3550 m^3/s to
reproduces the given quantities, and both sides carry the same units.
Why the other options are there
- 0.7100 — kept a factor of two that cancels in the correct rearrangement.
- 0.1775 — dropped that same factor in the other direction.
- 0.3905 — rounded an intermediate value before the final step.
Reference: FE Handbook — Multipath Pipeline Problems