Cage Drag Force
Sum signed collinear water-current drag across independently calibrated cage panels; area/coefficient must use consistent net-solidity basis and shielding/deformation are external.
Description
Signed quadratic drag expresses force along a shared current axis.
Signed quadratic drag expresses force along a shared current axis. Contributions from oppositely directed currents may cancel in the net force even while individual panel loads remain large.1
Sum signed collinear water-current drag across independently calibrated cage panels; area/coefficient must use consistent net-solidity basis and shielding/deformation are external.
When to use Cage Drag Force
Use this tool to sum signed collinear water-current drag across independently calibrated cage panels; area/coefficient must use consistent net-solidity basis and shielding/deformation are external.
Prepare the cohort, water, feed or equipment measurements for one consistent operating period. Confirm nitrogen reporting bases, dry/wet masses, flow units and supplied design assumptions.
How to use Cage Drag Force and understand its results
- Prepare the cohort, water, feed or equipment measurements for one consistent operating period. Confirm nitrogen reporting bases, dry/wet masses, flow units and supplied design assumptions.
- Enter waterDensityKgPerM3, normalCurrentSpeedsMPerSecond, projectedPanelAreasM2, calibratedDragCoefficients using the field table and calculation rules, then run the tool.
- Read signedPanelForcesNewtons, netNormalForceNewtons. The explanation below defines the units, signs, ordering and any flags or placeholder values.
- If the tool reports an input issue, correct the values and run it again. Apply the stated assumptions when interpreting a successfully returned result.
| Input field | Meaning | Value type; see rules below | Requirement |
|---|---|---|---|
| waterDensityKgPerM3 | Water density kg per m3 | number | Required |
| normalCurrentSpeedsMPerSecond | Normal current speeds m per second | list of number | Required |
| projectedPanelAreasM2 | Projected panel areas m2 | list of number | Required |
| calibratedDragCoefficients | Calibrated drag coefficients | list of number | Required |
Enter positive water density and aligned nonempty nonnegative panel areas/coefficients with signed velocities in m/s. Calculate each force in newtons and the signed sum along the common axis.
Paired lists must be nonempty and have equal lengths.
panelForce=0.5 waterDensity×area×dragCoefficient×velocity×|velocity|; net=ΣpanelForce Units, indexing, boundary conditions and exceptional cases are defined in the calculation rules above.
| Output field | Meaning | Value type |
|---|---|---|
| signedPanelForcesNewtons | Signed panel forces newtons | list of number |
| netNormalForceNewtons | Net normal force newtons | number |
{
"input": {
"waterDensityKgPerM3": 1000,
"normalCurrentSpeedsMPerSecond": [
1,
-2
],
"projectedPanelAreasM2": [
2,
1
],
"calibratedDragCoefficients": [
1,
0.5
]
},
"output": {
"signedPanelForcesNewtons": [
1000,
-1000
],
"netNormalForceNewtons": 0
}
}Limitations and assumptions
Coefficient and area conventions must match, including net porosity assumptions. Shielding, deformation, multidirectional flow and dynamic loading are excluded; net force alone does not describe every panel's demand.
Numeric inputs must be finite. Follow the calculation-specific rules for overflow, underflow and exceptional cases. Lists are limited to 100,000 entries; the rules above may require smaller limits. Missing required fields, extra fields, wrong value types and violations of the calculation rules are input errors.
Alternative or Complementary methods
Use Net Fouling Loss: Measure area-weighted net opening loss from panel porosity measurements; no hydraulic flow or drag change is inferred merely from loss of open area. For a complementary task, use Mooring Load: Solve horizontal two-line tension-only equilibrium for summed caller cage loads and fixed anchor bearings; distinct from windage drag, and catenaries, pretension, vertical load, waves and line strength are excluded.
References
-
Cage Drag Force — tool.io
Similar or alternative tools
- Net Fouling Loss
Measure area-weighted net opening loss from panel porosity measurements; no hydraulic flow or drag change is inferred merely from loss of open area.
- Mooring Load
Solve horizontal two-line tension-only equilibrium for summed caller cage loads and fixed anchor bearings; distinct from windage drag, and catenaries, pretension, vertical load, waves and line strength are excluded.