Group Velocity Deepwater Half Phase Calculator
Linear deepwater gravity-wave group velocity half phase velocity; no general finite-depth factor.
Description
Calculate deep-water group speed as half the supplied phase speed.
For linear deep-water gravity waves, group speed is half the phase speed. This calculator applies that relationship to a supplied phase speed.
When to use this tool
Calculate deep-water group speed as half the supplied phase speed. Use it when the input measurements and conventions below match the operation you need.
- Prepare phaseSpeedMPerS, respecting the measurement basis and boundaries below.
- Compare the worked example with your intended operation before reusing its result.
How to use the tool and how it works
- Enter every field in the input table using the stated units and exact supported selector spelling where applicable.
- Run the tool. Correct input errors before interpreting an output.
- Read the result fields below; use accompanying flags and the stated sign, boundary or model convention when interpreting a number.
The phase speed must be nonnegative. groupVelocity equals phaseVelocity divided by two, in the same speed units.1
| Input field | Meaning and units | Accepted input |
|---|---|---|
| phaseSpeedMPerS | Phase speed m per s. Meters per second. | Finite number; zero or greater |
| Output field | Interpretation |
|---|---|
| result | Object containing the following named result fields. |
| result.groupSpeedMPerS | Group speed mper s; use the stated units and sign convention. |
{
"input": {
"phaseSpeedMPerS": 10
},
"output": {
"result": {
"groupSpeedMPerS": 5
}
}
}Limitations and assumptions
- The deep-water relationship is assumed, not tested. Finite-depth waves, surface tension, currents and nonlinear effects require different treatment.
- Every declared field is required and unexpected fields are rejected. Numeric inputs must be finite; input errors are distinct from a valid false result or an explicitly qualified output.
- Extremely large inputs and nonfinite or excessively large outputs are rejected. List positions reported by the tool use zero-based indices unless stated otherwise.
Alternative or Complementary methods
Compare the result with independently checked observations or a model that covers the omitted dynamics. Use compatible frames, units and sampling conventions when carrying the value into another calculation. Compare the scope of the nearby tools below before substituting one.
References
Similar or alternative tools
- Deepwater Wave Phase Speed Calculator
Linear deepwater gravity-wave phase speed gT/(2pi); finite-depth and capillary effects omitted.
- Drifter Displacement Velocity Fixes Calculator
Signed segment velocities from actual common planar drifter fixes/time; not geodetic conversion or future trajectory.