Plume Mass Flux Buoyancy Estimate

Estimate signed heat-derived plume buoyancy flux using supplied source/ambient heat properties; neglects particle loading, moisture and momentum, retaining negatively buoyant thermal scenarios.

Description

Heat delivered by an eruptive source can drive buoyant plume motion.

Heat delivered by an eruptive source can drive buoyant plume motion. A cooler source gives a signed negative thermal excess.

Estimate signed heat-derived plume buoyancy flux using supplied source/ambient heat properties; neglects particle loading, moisture and momentum, retaining negatively buoyant thermal scenarios.

When to use Plume Mass Flux Buoyancy Estimate

Use this tool to estimate signed heat-derived plume buoyancy flux using supplied source/ambient heat properties; neglects particle loading, moisture and momentum, retaining negatively buoyant thermal scenarios.

Gather the relevant observations and fitted model parameters. Use the stated units and time basis; keep paired observations aligned.

How to use Plume Mass Flux Buoyancy Estimate and understand its results

Gather the relevant observations and fitted model parameters. Use the stated units and time basis; keep paired observations aligned.
Enter sourceMassFluxKgPerSecond, sourceTemperatureK, ambientTemperatureK, sourceSpecificHeatJPerKgK, ambientSpecificHeatJPerKgK, ambientDensityKgPerM3, gravityMPerSecondSquared using the field table and calculation rules, then run the tool.
Read thermalExcessPowerWatts, thermalBuoyancyFluxM4PerSecondCubed. 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
sourceMassFluxKgPerSecond	Source mass flux kg per second	number	Required
sourceTemperatureK	Source temperature k	number	Required
ambientTemperatureK	Ambient temperature k	number	Required
sourceSpecificHeatJPerKgK	Source specific heat j per kg k	number	Required
ambientSpecificHeatJPerKgK	Ambient specific heat j per kg k	number	Required
ambientDensityKgPerM3	Ambient density kg per m3	number	Required
gravityMPerSecondSquared	Gravity m per second squared	number	Required

Supply positive temperatures in kelvin, heat capacities, density and gravity, with nonnegative mass flux. Calculate source heat excess, then normalize by ambient properties. Preserve negative thermal power and buoyancy.^[1]

buoyancy flux = gravity × thermal power/(ambient density × ambient heat capacity × ambient temperature)

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

Output field	Meaning	Value type
thermalExcessPowerWatts	Thermal excess power watts	number
thermalBuoyancyFluxM4PerSecondCubed	Thermal buoyancy flux m4 per second cubed	number

json

{
  "input": {
    "sourceMassFluxKgPerSecond": 100,
    "sourceTemperatureK": 600,
    "ambientTemperatureK": 300,
    "sourceSpecificHeatJPerKgK": 1000,
    "ambientSpecificHeatJPerKgK": 1000,
    "ambientDensityKgPerM3": 1,
    "gravityMPerSecondSquared": 10
  },
  "output": {
    "thermalExcessPowerWatts": 30000000,
    "thermalBuoyancyFluxM4PerSecondCubed": 1000
  }
}

Limitations and assumptions

Particle loading, moisture and source momentum are omitted.

Numbers and computed results must be finite; overflow produces an error. Missing required fields, extra fields, wrong value types and violations of the calculation rules are input errors.

Alternative or Complementary methods

Use Umbrella Cloud Spread Radius: Balance uniform-thickness axisymmetric umbrella intrusion volume into radius, excluding wind shear, entrainment and sedimentation; not a mapped ash footprint or aviation warning. For a complementary task, use Eruption Column Height Estimation: Predict a calibrated power-law eruption column height above vent and datum elevation; coefficient units follow supplied exponent and no wind/eruption-style-independent plume law is guaranteed.

References

Plume Mass Flux Buoyancy Estimate — tool.io

Similar or alternative tools

Umbrella Cloud Spread Radius
Balance uniform-thickness axisymmetric umbrella intrusion volume into radius, excluding wind shear, entrainment and sedimentation; not a mapped ash footprint or aviation warning.
Eruption Column Height Estimation
Predict a calibrated power-law eruption column height above vent and datum elevation; coefficient units follow supplied exponent and no wind/eruption-style-independent plume law is guaranteed.