Rose Equation
Environmental Engineering · FE Reference Handbook section
Handbook notes for this section
Definitions and conditions exactly as the handbook states them.
- Monosized Media Multisized Media
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.
Rose equation headloss through a clean rapid sand filter bed Given drag coefficient (C_D) = 2.2000; filter media depth (L) = 0.7900 m; filtration velocity (v_f) = 0.0038 m/s; shape factor (phi) = 0.8700; gravitational acceleration (g) = 9.8100 m/s^2; grain diameter (d) = 0.0019 m; porosity (eps) = 0.4040, determine the headloss through clean bed (h_L) in m.
Given
Find
headloss through clean bed (h_L), in m
Start with the thinking
- The governing relation printed in this handbook section is Rose Equation.
- Everything except h_L is given, so isolate h_L 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.
- The Rose equation calculates head loss through a clean granular filter bed based on grain size, depth, and porosity.
Step-by-step solution
Step 1 — State the governing relation:
Step 2 — Rearrange symbolically for h_L:
Step 3 — List the givens: drag coefficient (C_D) = 2.2000, filter media depth (L) = 0.7900 m, filtration velocity (v_f) = 0.0038 m/s, shape factor (phi) = 0.8700, gravitational acceleration (g) = 9.8100 m/s^2, grain diameter (d) = 0.0019 m, porosity (eps) = 0.4040.
Step 4 — Substitute the given values:
Step 5 — Evaluate:
Step 6 — Check: returning h_L = 0.0620 m to
reproduces the given quantities, and both sides carry the same units.
Why the other options are there
- 0.1240 — kept a factor of two that cancels in the correct rearrangement.
- 0.0310 — dropped that same factor in the other direction.
- 0.0682 — rounded an intermediate value before the final step.
Reference: FE Handbook — Rose Equation (filter headloss)
Rose equation used to estimate clean-bed head loss in filtration Given drag coefficient (C_D) = 1.6500; filtration velocity (v_f) = 0.0027 m/s; shape factor (phi) = 0.7800; gravitational acceleration (g) = 9.8100 m/s^2; grain diameter (d) = 0.0009 m; porosity (eps) = 0.3990; headloss through clean bed (h_L) = 0.6650 m, determine the filter media depth (L) in m.
Given
Find
filter media depth (L), in m
Start with the thinking
- The governing relation printed in this handbook section is Rose Equation.
- Everything except L is given, so isolate L 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.
- The Rose equation calculates head loss through a clean granular filter bed based on grain size, depth, and porosity.
Step-by-step solution
Step 1 — State the governing relation:
Step 2 — Rearrange symbolically for L:
Step 3 — List the givens: drag coefficient (C_D) = 1.6500, filtration velocity (v_f) = 0.0027 m/s, shape factor (phi) = 0.7800, gravitational acceleration (g) = 9.8100 m/s^2, grain diameter (d) = 0.0009 m, porosity (eps) = 0.3990, headloss through clean bed (h_L) = 0.6650 m.
Step 4 — Substitute the given values:
Step 5 — Evaluate:
Step 6 — Check: returning L = 8.7422 m to
reproduces the given quantities, and both sides carry the same units.
Why the other options are there
- 17.4844 — kept a factor of two that cancels in the correct rearrangement.
- 4.3711 — dropped that same factor in the other direction.
- 9.6164 — rounded an intermediate value before the final step.
Reference: FE Handbook — Rose Equation (filter headloss)
Rose equation filter headloss calculation for uniform media Given drag coefficient (C_D) = 1.6500; filter media depth (L) = 1.4600 m; shape factor (phi) = 0.7500; gravitational acceleration (g) = 9.8100 m/s^2; grain diameter (d) = 0.0013 m; porosity (eps) = 0.3910; headloss through clean bed (h_L) = 0.7850 m, determine the filtration velocity (v_f) in m/s.
Given
Find
filtration velocity (v_f), in m/s
Start with the thinking
- The governing relation printed in this handbook section is Rose Equation.
- Everything except v_f is given, so isolate v_f 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.
- The Rose equation calculates head loss through a clean granular filter bed based on grain size, depth, and porosity.
Step-by-step solution
Step 1 — State the governing relation:
Step 2 — Rearrange symbolically for v_f:
Step 3 — List the givens: drag coefficient (C_D) = 1.6500, filter media depth (L) = 1.4600 m, shape factor (phi) = 0.7500, gravitational acceleration (g) = 9.8100 m/s^2, grain diameter (d) = 0.0013 m, porosity (eps) = 0.3910, headloss through clean bed (h_L) = 0.7850 m.
Step 4 — Substitute the given values:
Step 5 — Evaluate:
Step 6 — Check: returning v_f = 0.0083 m/s to
reproduces the given quantities, and both sides carry the same units.
Why the other options are there
- 0.0165 — kept a factor of two that cancels in the correct rearrangement.
- 0.0041 — dropped that same factor in the other direction.
- 0.0091 — rounded an intermediate value before the final step.
Reference: FE Handbook — Rose Equation (filter headloss)
Rose equation headloss through a clean rapid sand filter bed Given drag coefficient (C_D) = 0.5800; filter media depth (L) = 1.2300 m; filtration velocity (v_f) = 0.0043 m/s; shape factor (phi) = 0.9500; gravitational acceleration (g) = 9.8100 m/s^2; grain diameter (d) = 0.0005 m; porosity (eps) = 0.4080, determine the headloss through clean bed (h_L) in m.
Given
Find
headloss through clean bed (h_L), in m
Start with the thinking
- The governing relation printed in this handbook section is Rose Equation.
- Everything except h_L is given, so isolate h_L 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.
- The Rose equation calculates head loss through a clean granular filter bed based on grain size, depth, and porosity.
Step-by-step solution
Step 1 — State the governing relation:
Step 2 — Rearrange symbolically for h_L:
Step 3 — List the givens: drag coefficient (C_D) = 0.5800, filter media depth (L) = 1.2300 m, filtration velocity (v_f) = 0.0043 m/s, shape factor (phi) = 0.9500, gravitational acceleration (g) = 9.8100 m/s^2, grain diameter (d) = 0.0005 m, porosity (eps) = 0.4080.
Step 4 — Substitute the given values:
Step 5 — Evaluate:
Step 6 — Check: returning h_L = 0.1090 m to
reproduces the given quantities, and both sides carry the same units.
Why the other options are there
- 0.2180 — kept a factor of two that cancels in the correct rearrangement.
- 0.0545 — dropped that same factor in the other direction.
- 0.1199 — rounded an intermediate value before the final step.
Reference: FE Handbook — Rose Equation (filter headloss)
Rose equation used to estimate clean-bed head loss in filtration Given drag coefficient (C_D) = 2.8600; filtration velocity (v_f) = 0.0040 m/s; shape factor (phi) = 0.8600; gravitational acceleration (g) = 9.8100 m/s^2; grain diameter (d) = 0.0020 m; porosity (eps) = 0.4470; headloss through clean bed (h_L) = 0.8400 m, determine the filter media depth (L) in m.
Given
Find
filter media depth (L), in m
Start with the thinking
- The governing relation printed in this handbook section is Rose Equation.
- Everything except L is given, so isolate L 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.
- The Rose equation calculates head loss through a clean granular filter bed based on grain size, depth, and porosity.
Step-by-step solution
Step 1 — State the governing relation:
Step 2 — Rearrange symbolically for L:
Step 3 — List the givens: drag coefficient (C_D) = 2.8600, filtration velocity (v_f) = 0.0040 m/s, shape factor (phi) = 0.8600, gravitational acceleration (g) = 9.8100 m/s^2, grain diameter (d) = 0.0020 m, porosity (eps) = 0.4470, headloss through clean bed (h_L) = 0.8400 m.
Step 4 — Substitute the given values:
Step 5 — Evaluate:
Step 6 — Check: returning L = 11.3575 m to
reproduces the given quantities, and both sides carry the same units.
Why the other options are there
- 22.7150 — kept a factor of two that cancels in the correct rearrangement.
- 5.6787 — dropped that same factor in the other direction.
- 12.4932 — rounded an intermediate value before the final step.
Reference: FE Handbook — Rose Equation (filter headloss)
Rose equation filter headloss calculation for uniform media Given drag coefficient (C_D) = 8.9700; filter media depth (L) = 0.9500 m; shape factor (phi) = 0.8200; gravitational acceleration (g) = 9.8100 m/s^2; grain diameter (d) = 0.0018 m; porosity (eps) = 0.4300; headloss through clean bed (h_L) = 1.6550 m, determine the filtration velocity (v_f) in m/s.
Given
Find
filtration velocity (v_f), in m/s
Start with the thinking
- The governing relation printed in this handbook section is Rose Equation.
- Everything except v_f is given, so isolate v_f 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.
- The Rose equation calculates head loss through a clean granular filter bed based on grain size, depth, and porosity.
Step-by-step solution
Step 1 — State the governing relation:
Step 2 — Rearrange symbolically for v_f:
Step 3 — List the givens: drag coefficient (C_D) = 8.9700, filter media depth (L) = 0.9500 m, shape factor (phi) = 0.8200, gravitational acceleration (g) = 9.8100 m/s^2, grain diameter (d) = 0.0018 m, porosity (eps) = 0.4300, headloss through clean bed (h_L) = 1.6550 m.
Step 4 — Substitute the given values:
Step 5 — Evaluate:
Step 6 — Check: returning v_f = 0.0095 m/s to
reproduces the given quantities, and both sides carry the same units.
Why the other options are there
- 0.0189 — kept a factor of two that cancels in the correct rearrangement.
- 0.0047 — dropped that same factor in the other direction.
- 0.0104 — rounded an intermediate value before the final step.
Reference: FE Handbook — Rose Equation (filter headloss)
Rose equation headloss through a clean rapid sand filter bed Given drag coefficient (C_D) = 2.1400; filter media depth (L) = 0.7800 m; filtration velocity (v_f) = 0.0045 m/s; shape factor (phi) = 0.8700; gravitational acceleration (g) = 9.8100 m/s^2; grain diameter (d) = 0.0004 m; porosity (eps) = 0.3700, determine the headloss through clean bed (h_L) in m.
Given
Find
headloss through clean bed (h_L), in m
Start with the thinking
- The governing relation printed in this handbook section is Rose Equation.
- Everything except h_L is given, so isolate h_L 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.
- The Rose equation calculates head loss through a clean granular filter bed based on grain size, depth, and porosity.
Step-by-step solution
Step 1 — State the governing relation:
Step 2 — Rearrange symbolically for h_L:
Step 3 — List the givens: drag coefficient (C_D) = 2.1400, filter media depth (L) = 0.7800 m, filtration velocity (v_f) = 0.0045 m/s, shape factor (phi) = 0.8700, gravitational acceleration (g) = 9.8100 m/s^2, grain diameter (d) = 0.0004 m, porosity (eps) = 0.3700.
Step 4 — Substitute the given values:
Step 5 — Evaluate:
Step 6 — Check: returning h_L = 0.5369 m to
reproduces the given quantities, and both sides carry the same units.
Why the other options are there
- 1.0737 — kept a factor of two that cancels in the correct rearrangement.
- 0.2684 — dropped that same factor in the other direction.
- 0.5905 — rounded an intermediate value before the final step.
Reference: FE Handbook — Rose Equation (filter headloss)
Rose equation used to estimate clean-bed head loss in filtration Given drag coefficient (C_D) = 6.9800; filtration velocity (v_f) = 0.0040 m/s; shape factor (phi) = 0.8500; gravitational acceleration (g) = 9.8100 m/s^2; grain diameter (d) = 0.0004 m; porosity (eps) = 0.4540; headloss through clean bed (h_L) = 1.2580 m, determine the filter media depth (L) in m.
Given
Find
filter media depth (L), in m
Start with the thinking
- The governing relation printed in this handbook section is Rose Equation.
- Everything except L is given, so isolate L 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.
- The Rose equation calculates head loss through a clean granular filter bed based on grain size, depth, and porosity.
Step-by-step solution
Step 1 — State the governing relation:
Step 2 — Rearrange symbolically for L:
Step 3 — List the givens: drag coefficient (C_D) = 6.9800, filtration velocity (v_f) = 0.0040 m/s, shape factor (phi) = 0.8500, gravitational acceleration (g) = 9.8100 m/s^2, grain diameter (d) = 0.0004 m, porosity (eps) = 0.4540, headloss through clean bed (h_L) = 1.2580 m.
Step 4 — Substitute the given values:
Step 5 — Evaluate:
Step 6 — Check: returning L = 1.4959 m to
reproduces the given quantities, and both sides carry the same units.
Why the other options are there
- 2.9919 — kept a factor of two that cancels in the correct rearrangement.
- 0.7480 — dropped that same factor in the other direction.
- 1.6455 — rounded an intermediate value before the final step.
Reference: FE Handbook — Rose Equation (filter headloss)
Rose equation filter headloss calculation for uniform media Given drag coefficient (C_D) = 9.5600; filter media depth (L) = 0.7300 m; shape factor (phi) = 0.7400; gravitational acceleration (g) = 9.8100 m/s^2; grain diameter (d) = 0.0013 m; porosity (eps) = 0.4860; headloss through clean bed (h_L) = 0.3790 m, determine the filtration velocity (v_f) in m/s.
Given
Find
filtration velocity (v_f), in m/s
Start with the thinking
- The governing relation printed in this handbook section is Rose Equation.
- Everything except v_f is given, so isolate v_f 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.
- The Rose equation calculates head loss through a clean granular filter bed based on grain size, depth, and porosity.
Step-by-step solution
Step 1 — State the governing relation:
Step 2 — Rearrange symbolically for v_f:
Step 3 — List the givens: drag coefficient (C_D) = 9.5600, filter media depth (L) = 0.7300 m, shape factor (phi) = 0.7400, gravitational acceleration (g) = 9.8100 m/s^2, grain diameter (d) = 0.0013 m, porosity (eps) = 0.4860, headloss through clean bed (h_L) = 0.3790 m.
Step 4 — Substitute the given values:
Step 5 — Evaluate:
Step 6 — Check: returning v_f = 0.0051 m/s to
reproduces the given quantities, and both sides carry the same units.
Why the other options are there
- 0.0102 — kept a factor of two that cancels in the correct rearrangement.
- 0.0025 — dropped that same factor in the other direction.
- 0.0056 — rounded an intermediate value before the final step.
Reference: FE Handbook — Rose Equation (filter headloss)
Rose equation headloss through a clean rapid sand filter bed Given drag coefficient (C_D) = 8.2500; filter media depth (L) = 0.8000 m; filtration velocity (v_f) = 0.0028 m/s; shape factor (phi) = 0.9400; gravitational acceleration (g) = 9.8100 m/s^2; grain diameter (d) = 0.0011 m; porosity (eps) = 0.4810, determine the headloss through clean bed (h_L) in m.
Given
Find
headloss through clean bed (h_L), in m
Start with the thinking
- The governing relation printed in this handbook section is Rose Equation.
- Everything except h_L is given, so isolate h_L 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.
- The Rose equation calculates head loss through a clean granular filter bed based on grain size, depth, and porosity.
Step-by-step solution
Step 1 — State the governing relation:
Step 2 — Rearrange symbolically for h_L:
Step 3 — List the givens: drag coefficient (C_D) = 8.2500, filter media depth (L) = 0.8000 m, filtration velocity (v_f) = 0.0028 m/s, shape factor (phi) = 0.9400, gravitational acceleration (g) = 9.8100 m/s^2, grain diameter (d) = 0.0011 m, porosity (eps) = 0.4810.
Step 4 — Substitute the given values:
Step 5 — Evaluate:
Step 6 — Check: returning h_L = 0.0981 m to
reproduces the given quantities, and both sides carry the same units.
Why the other options are there
- 0.1962 — kept a factor of two that cancels in the correct rearrangement.
- 0.0491 — dropped that same factor in the other direction.
- 0.1079 — rounded an intermediate value before the final step.
Reference: FE Handbook — Rose Equation (filter headloss)