neqsim-flow-induced-vibration-screening

name	neqsim-flow-induced-vibration-screening
version	0.1.0
description	Educational flow-induced vibration (FIV) screening using a public fluid kinetic-energy (rho v^2) likelihood-of-failure index. USE WHEN: a task needs a public, screening-level check of whether a main-line flow velocity and density produce a kinetic-energy level that warrants a detailed Energy Institute style FIV assessment before piping vibration design.
last_verified	2026-06-18
requires	{"python_packages":[],"java_packages":[],"env":[],"network":[]}

Flow-Induced Vibration Screening

Use this skill for public, educational flow-induced vibration (FIV) screening. It computes a fluid kinetic-energy index rho v^2 and compares it to a configurable kinetic-energy threshold so an agent can flag piping that may need a detailed Energy Institute style FIV likelihood-of-failure assessment before vibration design.

When to Use

• When a user asks whether a line could be prone to flow-induced vibration.
• When an agent needs a quick kinetic-energy triage to scope a piping vibration study.
• When examples must run without confidential piping classes, project line lists, or company piping specs.

Inputs

• fluid_velocity: actual flowing velocity in the line in m/s.
• mixture_density: flowing mixture density in kg/m3.
• kinetic_energy_threshold: screening kinetic-energy threshold in Pa, default 10000.0.
• small_bore_present: optional flag that a small-bore connection or thermowell is present, default False.

Outputs

• kinetic_energy_pa: fluid kinetic-energy index rho v^2 in Pa.
• threshold_ratio: ratio of the kinetic energy to the screening threshold.
• likelihood_of_failure_band: qualitative low, medium, or high band.
• fiv_warning: ok, watch, or high.
• small_bore_flag: True when a small-bore connection raises the screening sensitivity.
• assumptions: public assumptions used by the placeholder model.

Engineering Method

The Python class FlowInducedVibrationModel uses an open, published screening concept only:

• the fluid kinetic energy uses the widely published index FKE = rho v^2, the same quantity used as the primary driver in public Energy Institute style FIV likelihood-of-failure screening.
• the threshold ratio compares the kinetic energy to a configurable screening threshold.
• a small-bore connection flag lowers the effective warning thresholds because small-bore and thermowell connections are a common FIV failure location.
• the likelihood-of-failure band is a simple rule-based label derived from the threshold ratio.

This is educational and screening-only logic. It does not reproduce the proprietary Energy Institute Guidelines, scoring tables, or correction factors. It is not a vibration standard, a fatigue method, a modal analysis, or a replacement for a qualified piping vibration assessment.

Python Usage Pattern

from flow_induced_vibration_screening import FlowInducedVibrationModel

model = FlowInducedVibrationModel()
result = model.evaluate(
    fluid_velocity=20.0,
    mixture_density=60.0,
    kinetic_energy_threshold=10000.0,
    small_bore_present=False,
)

print(result.fiv_warning)
print(result.kinetic_energy_pa)
print(result.likelihood_of_failure_band)

If the optional neqsim Python package is available, the result records that fact so an agent can recommend moving to validated NeqSim property models for mixture density and velocity, followed by a detailed FIV assessment. If it is not installed, the example still runs with public placeholder logic.

Related NeqSim Functionality

NeqSim already implements a validated Energy Institute style FIV likelihood-of-failure model. Redirect real assessments to:

• neqsim.process.measurementdevice.FlowInducedVibrationAnalyser — likelihood-of-failure analyser attached to a pipe segment.
• neqsim.process.mechanicaldesign.manifold.ManifoldMechanicalDesignCalculator — acoustic-induced vibration (AIV) likelihood-of-failure for manifold piping.

This skill is a public rho v^2 triage layer that decides when to invoke FlowInducedVibrationAnalyser for a full assessment.

Validation Checklist

• Inputs are positive and densities and velocities are in SI units.
• Example inputs are public and synthetic.
• Tests cover low, warning, high, small-bore, and invalid-input cases.
• Results are described as educational screening indicators.
• Real FIV assessment is redirected to validated methods, Energy Institute guidelines, and qualified review.

Common Mistakes

Symptom	Cause	Fix
Kinetic energy looks too low	Density taken at standard rather than flowing conditions	Evaluate density at line pressure and temperature
Threshold never triggers	Threshold set above realistic main-line limits	Use a service-appropriate threshold and consider the small-bore flag
Result treated as a fatigue life	Confusing screening with assessment	Move to a detailed FIV likelihood-of-failure assessment

Limitations

• No proprietary Energy Institute scoring tables, correction factors, or fatigue calculations are included.
• No mechanical, modal, acoustic, or support-stiffness analysis is performed.
• No transient, slug, or two-phase intermittency excitation is modelled.

References

• NeqSim repository: https://github.com/equinor/neqsim
• NeqSim Skills Guide: https://github.com/equinor/neqsim/blob/master/docs/integration/skills_guide.md