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.

Description

Net fouling reduces open area relative to a clean reference.

Net fouling reduces open area relative to a clean reference. Weighting each panel by its physical area accounts for unequal panel sizes.^[1]

Measure area-weighted net opening loss from panel porosity measurements; no hydraulic flow or drag change is inferred merely from loss of open area.

When to use Net Fouling Loss

Use this tool to measure area-weighted net opening loss from panel porosity measurements; no hydraulic flow or drag change is inferred merely from loss of open area.

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 Net Fouling Loss 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 cleanOpenAreaFractions, fouledOpenAreaFractions, panelAreasM2 using the field table and calculation rules, then run the tool.
Read cleanEffectiveOpenAreaM2, fouledEffectiveOpenAreaM2, relativeOpenAreaLossFraction. 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
cleanOpenAreaFractions	Clean open area fractions	list of number	Required
fouledOpenAreaFractions	Fouled open area fractions	list of number	Required
panelAreasM2	Panel areas m2	list of number	Required

Enter aligned nonempty positive panel areas, clean opening fractions greater than zero through one and fouled fractions from zero through the corresponding clean fraction. Return clean and fouled open areas and their fractional loss.

Paired lists must be nonempty and have equal lengths.

cleanOpen=ΣpanelArea×cleanFraction; fouledOpen=ΣpanelArea×fouledFraction; loss=1−fouledOpen/cleanOpen

Units, indexing, boundary conditions and exceptional cases are defined in the calculation rules above.

Output field	Meaning	Value type
cleanEffectiveOpenAreaM2	Clean effective open area m2	number
fouledEffectiveOpenAreaM2	Fouled effective open area m2	number
relativeOpenAreaLossFraction	Relative open area loss fraction	number

json

{
  "input": {
    "cleanOpenAreaFractions": [
      0.8,
      0.6
    ],
    "fouledOpenAreaFractions": [
      0.4,
      0.3
    ],
    "panelAreasM2": [
      10,
      20
    ]
  },
  "output": {
    "cleanEffectiveOpenAreaM2": 20,
    "fouledEffectiveOpenAreaM2": 10,
    "relativeOpenAreaLossFraction": 0.5
  }
}

Limitations and assumptions

Open-area loss is not directly a flow or drag loss. Fouling distribution, current direction and changes in net geometry are not modeled.

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 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. 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

Net Fouling Loss — tool.io

Similar or alternative tools

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.
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.